I recently bought a nice, lightly used rifle and a higher end used scope (separate purchases). My first 2 range trips showed a lot of promise with every hand load I tried shooting 1.25" or better at 100 yd, and several shooting 3/4" or better for 5 shots. Yesterday I moved out to 200 yd with a load that had shot very well previously at 100yd and things went haywire. I shot 8 shots and had a 5" pattern. Frustrated, I moved back to my 100 target and rattled off a 4 shot group just under 3/4".
I left puzzled and ran to my local shop and picked up a box of factory ammo to try. Today I went back to the range with my brother to let him shoot it and eliminate me as a variable. His 1st group at 200 yrds was 3.5" with my hand loads, then he shot another 3.5" group with the factory ammo. Then I shot the factory ammo at 100 and it went into an honest 1/4" group!!! Then I shot the factory ammo at 200 at it was about 3", so we packed it up for the day.

I'm looking for suggestions and help. I have my theory on the problem, but I'm looking to the brain trust here for answers. Nothing really makes sense. HELP!!!!!

Scope parallax or wind would be my first guesses.

Canted reticle??

A canted reticle won't cause it, but tilting the rifle different ways from shot to shot will.

As will parallax and wind, as centershot pointed out. The effect of wind-drift doesn't just double at twice the range: Instead it basically quadruples.

My guess too is parallax. One can even have a reversal. Garbage at 100 and then a tightening when stretched out.

Any pattern to ones dispersal? Vertical, horizontal, or pretty much circular?

I'm pretty sure I can rule out the rifle tilt and the wind was less than 5 mph on both days, so that is out too. I'm assuming parallax issue, which we tried to adjust that prior to the 2nd day of shooting, but it didn't seem to help.

The 2 groups my brother shot yesterday were almost vertical, but mine were all over the place......

According to this article it has the same effect ...

https://www.shootingillustrated.com/articles/2016/3/28/rifle-scope-reticle-cant/

country 20boy,

I'm guessing there's something gone wrong with the parallax, for whatever reason. Vertical stringing is often a sign of excess parallax, because the comb of the stock tends to keep our eye in vertical line with the reticle, but not so much up and down, unless we have a really firm cheek weld.

Parallax seems to be the consensus. I'm going to swap some scopes around later this week and try again. I'll keep you posted, but it looks like this one is headed back to Oregon for repairs......

You answered your own question, think about it...

I always get bigger groups as the range increases. When it quits being MOA moose I have reached my max shooting distance. I respect guys that can hold small groups past 300 yards, wish I could.

Country 20boy, isn't this much better than starting a thread in "Hunting Rifles" just to let Big Stick prance around schitting all over it?

I find it interesting that nowhere does the OP state what caliber, bullet, rifle make and model, scope make and model and the automatic consensus is parallax due to one guy stringing and the next shooter shotgunning. I can think of a bunch more variables to throw in from shooter to shooter than parallax.

Amen......

ya kinda would like to know more details too ? brand rifle ? bolt action,pump or semi auto ? brand and power of scope ? cartridge used ? brand of ammo ? brand of scope mnts. ? what kinda rests were you using ? maybe a picture too ? you want answers we need better info ? some us can help you

I intentionally left out a lot of info, so that no one would jump to conclusions based solely on the brand names...... I also didn't want to point fingers at anyone who may have sold me a junk scope or rifle......and I'm still not.

But here you go:
Nosler M48 in 7mm-08
Leupold VX-5HD
Talley rings
Handloaded bullets were 150 ELDX with RL-15 powder
Factory ammo was Fed. Premium 140 NBT

Rifle was on sand bags, front and rear. Same as I've done hundreds of times with a dozen different rifles.

Believe me, after my Saturday range session, I was questioning everything. That's why I brought along another shooter on Sunday and grabbed some factory ammo. Trying to eliminate 1 variable at a time......
I'm usually a pretty decent bench shooter and I've never seen anything like this. My other guns always hold about the same relative group size. I.E., 1/2" groups at 100 = 1" groups at 200 and 2" groups at 400....

If you have any ideas or suggestions, I'm listening.....

Me too. One factor may simply be that there's too few groups to draw any particularly meaningful conclusions.

The issue with parallax that I see is that any error attributable to it, on the given facts, is likely to be small. If we take it that the rifle shoots well at 100 it seems likely that parallax isn't an issue at that distance. If it is more or less parallax-free at 100 then the maximum error attributable to parallax at 200 is about 1/2 the diameter of the objective lens, for an eye at the extreme edge of the exit pupil. That is about 0.4 moa maximum, for a 40mm objective lens. If we allow for a shooter whose eye position is so inconsistent that they go from one extreme edge of the exit pupil to the other between shots we could add up to 0.8 moa. That is the extreme case though, and would be a technique issue at least as much as a scope issue.

It may be a factor, I guess. I suspect that it isn't the whole story, nor is it the only possibility.

thanks thats a nice rifle and equipment, i wonder: try a different scope on this rifle 1st ? if that don`t help send that rifle back to Nosler that barrel is bad i think ? 7mm-08 in that rifle should shoot 1/2 inch easy at 100 yards, my 7mm-08`s all do, and less or atleast 1 inch at 200 yards. that`s just wrong sorry . i had a new Cooper that did the same thing so i called Cooper they took rifle back and replaced barrel ,now it shoots great. call Nosler,good luck,Pete53

What magnification were you shooting at? If it's a variable, did you try dialing it down to 6x or so to lessen the effect of parallax?

Also, inconsistent MV's are more likely to open up groups as distance increases.

Try a different scope on that rifle, with nothing else changed.

Try that scope on a rifle known to be accurate.

I have that bloke on "ignore". His contributions are not worth reading, and so I don't read them.

country,

Did you actually measure the wind, or estimate it?

Dont send it here. I just toss them as far as i can, when they go bad.. Try one of those chinese knockoffs, it might be better..

These guys will help you now maybe, but the way your original post sounded was like calling to get your car fixed, My car isn’t running right need it fixed and how much? make don’t know, model don’t know, engine don’t know, then how can I know how to fix it?
Don’t, but you got a lot of guessing advice without all that info but I bet the car wasn’t running right due to parallax.

Are you shooting both target ranges at the same magnification?

Estimate and also looked at weather app. Trust me the wind was a non factor.

Yes.

I highly doubt its a true "1/2 moa" rifle, even at 100. Those, as we all know, are hard to come by.

Why was the wind a non-factor? Was it blowing steadily from one direction? Or was it switching a little?

We still don't even know the bullet/velocity, etc. A 5 mph wind (which many shooters would consider a non-factor) switching back and forth can result in considerable effect on groups at 200 yards.

MD, anything I posted wasn’t a dig on you as I value your knowledge. The reason I quoted this is you are 100% correct. There’s a reason for wind flags.

Swifty,

I appreciate that, and I wasn't reacting to your post.

The problem could also be a combination of factors, not just one. In my experience problems with scope parallax (including such stuff as loose reticle cells, which don't always show up on every shot) and wind are two VERY common factors in group size beyond 100 yards. Wind, in fact, the the big reason for the myth that bullets lose stability at longer ranges.

Then there's the human element, which we just witnessed in the thread on light rifles, where one shooter shot tight groups and another shot scatters under the same conditions. Just because two shooters got comparable results at 100 and 200 doesn't mean those are the ONLY possible results.

I agree. Never said it was a 1/2" rifle and it's suspect at best right now....

So is it a "double-secret probation" rifle?

The wind was almost straight at me and 2-3 mph.
7mm08
150 ELDX were chrono'd at 2720 fps previously.
The factory 140 NBT haven't been verified but I would assume about 2800.
My apologies if I came across as defensive. I know you and others here have vastly more experience than me.
I do know enough to know that something isn't right and it's bothering me. It will probably be next weekend before I can test it again....
Thanks for your help.

OK

The title of your thread says "why would a rifle shoot 1/2 moa at 100 yards and 2 moa at 200 yards". I didnt say it was a "1/2" rifle" either. There is a difference. If you want help, you need to know and understand the difference. I also think its a parallax issue, as i have lost all faith in leupold rifle scopes. Ive seen so many go tits up, it isn't even funny. Vortex is in the same boat. When evaluating the accuracy potential of a rifle, one of the general rules (for myself) is to start with a "proven" rifle scope and mounting system. If you buy a rifle that already has bases and rings attached, pull them. I make damn sure everything is de-greased and ill go through the extra bit and chase/clean up the tapped holes in the receiver, check screws for proper length (to be sure they arent going to bottom out prematurely), use blue loctite and make sure everything is tight and perfectly lined up. As ive said before, out of alignment rings puts uneven pressure on the scope tube, which may allow the scope to move during recoil. What some dont realize is, if the scope twists or moves, just a minuscule amount, it will have a profound affect on accuracy. If you dont believe me, do a little test with said rifle: Get it all zeroed, then pull the scope off, tighten it back up and see where your poi shifts. It may be an eye opener. Thats why it may be necessary to lap your rings and in some extreme cases, even bed your bases. Furthermore, Im not saying its a bad shooter or bad rifle, but you need to make sure your bases are well covered and your foundation established, before pulling the trigger, if you are in search consistent accuracy in a rifle. Jb has been hitting the nail on the head, you may want to pick up some of his books or search out articles regarding accuracy enhancements, rifle accurizing etc. I havent bought a magazine in over a decade, but i know accurizing tips and tricks were always a hot item, discussed by JB's buddies in rifleshooter.

Just got back to this, while you do have a good point, I did some digging.
Nosler only guarantees 1 model, full custom to shoot 3 shots into 3/4” at 100. And that’s with Nosler approved ammo only. 😀
All the other M48’s are only to expect 1 MOA or less at 100.
1 MOA is 1.047” at 100. So if it shoots 3 shots into 1.02 then it’s meeting the accuracy guarantee. 😀
1 MOA @ 200 = roughly 2.094 if it can hold true MOA.
So if it’s shooting 2” @ 200 then it’s actually bettering the guarantee. But I still wouldn’t call 2.5”- 3” out of the realm of normal with out match grade ammo.
I still don’t think it’s parallax, but more him expecting more than the rifle and ammo can do without tuning or a little more work.

I disagree. Maybe with an inexperienced shooter, your viewpoint has some validity, but with someone who has BTDT, shooting off a good bench or rest, if the optics are fine, the group isn't going to open up like that. At least I have never seen it over thousands of rounds in about 2 dozen rifles, and while watching many thousands more fired in at least 2 dozen other rifles and involving at least 20 other shooters. Unless something wonky happens with the bullets, the cone of the load's ability and the shooter's ability to group are going to be roughly linear, if wind is a non-factor. I've been involved in teaching several kids to shoot rifles with magnifying optics, and it is just as true with them. If they can shoot 1" at 50 yds, they basically shoot 2" at 100, 4" at 200, and roughly 6" at 300.

Told you I did some digging

https://www.americanrifleman.org/articles/2016/1/25/the-28-nosler/



Seems even MD couldn’t get one to average under an inch @ 100. Guess he’s inexperienced.
Also read couple of reviews on the 7-08 and not one of them averaged under an inch.

I guess I was under the mistaken impression that we were discussing the rifle of the OP. Which did shot MOA at 100. More than once.

I'm with you HuntnShoot. I think something is wrong, but I'm going to have to do some more testing to figure it out. As I said before, I'm not a professional or a trained sniper, but when I can sit down and shoot multiple groups of 3/4" or better at 100 and then 3"-5" at 200, something is off.........

Again, the op says 2 moa at 200 yards, that is a little bigger than 4" at that range. So what he's actually saying in the title of the thread, it's shooting about 1/2" at a 100 and a little more than 4" at 200.

I recently bought a nice, lightly used rifle and a higher end used scope (separate purchases). My first 2 range trips showed a lot of promise with every hand load I tried shooting 1.25" or better at 100 yd, and several shooting 3/4" or better for 5 shots. Yesterday I moved out to 200 yd with a load that had shot very well previously at 100yd and things went haywire. I shot 8 shots and had a 5" pattern. Frustrated, I moved back to my 100 target and rattled off a 4 shot group just under 3/4".





Personally I have had that happen with 3 rifles guaranteed 1/2 or better bought new. Fugging load they shot the target with beat the guarantee @ 100 fell the hell apart at the 2 and 3. Tweak here and there bingo. Had deer rifles do the same thing. Great at the 1 suck at the 2 and 3.
Nosler says expect, not guaranteed as I posted before. And I didn’t mis-read.

Mirage ?

With all these 5 shot groups, and I am assuming a newer rifle.

Could the bore be getting fouled?

Have you scoped the bore?

So what kind of tweaks? Bedding? Forend pressure? Action screws?

Bought used. Supposedly less than 200 rounds.
I cleaned the bore good this week and it didn't seem to be excessively dirty. I changed mounts (talleys) and scopes (conquest) and shot a few groups this morning. Didn't have a lot of time, but it appears to be more of the same.

Shot groups of 3.5", 5", and 2" at 200 yards and shot just over 3/4" at 100.

If the load that shot the 2” group was the same as the 3/4 then I would tweak around that. Plus if that is successive shrinking of groups at the 2, then don’t clean it. Forget the 1 and just work at the 2.

Some more comments on this thread:

First, we still don't know the make of rifle, cartridge, or anything about the ammo.

At first country boy said the wind wasn't over 5 mph, then admitted he had no way to measure it, other than guessing and looking at the local weather report. Then he said it was 2-3 mph, straight on.

We also don't the brand of either scope, or whether either is actually adjustable for parallax. Just because a second scope was tried doesn't mean the second wasn't part of the problem. Several years ago a guy on the Campfire asked me for a good powder/charge for 165's for the .30-06, as he'd just bought one, a model well-known for accuracy. I told him around 58 grains of H4350, and as I recall even suggested a bullet to start with. He couldn't get it to shoot, so I suggested trying another, proven scope. He still couldn't get it to shoot, and I didn't hear from him for a few months. At that point he PM'd me, admitting BOTH scopes were brand-new. He'd finally tried an old beater scope he had, as I recall maybe even a 4x, M8 Leupold. All of sudden the rifle started shooting sub-inch groups with the same load.

We're still lacking a bunch of info, and along with that, many of these rifle-diagnoses threads never get resolved because often its impossible to analyze what's wrong without being there.

Swifty, did you read the article on the 28 Nosler accompanying the handload chart you posted?

I do have some old Sinclair windflags, maybe not as sensitive as today's best but better than my ability anyway, and a bore scope and an Oehler proof chronograph, and parallax adjustable high power scopes that have a relatively narrow depth of field and remind me that the cross hairs and the target can move together or opposite to tell me which way to adjust and a good classic - not joy stick - rest and sandbags and on a good day - diurnal reversal low wind helps - I've shot some bragging groups. My experience has been in line with my reading that at some range the external ballistics will make the group go trumpet shaped that is the group will expand gradually up to a point then start getting much larger and larger yet - but not until the range is much more extended - obvious explanations like bullets coming apart and weird terrain and wind interaction excepted.

On the other hand I have also found that testing loads only at short range is a snare and a delusion and everything looks good at 50 yards and small differences at 100 yards can grow and be obvious at 300 yards and more. Mostly I have figured a difference in wind bucking and winds way out there, maybe bullet noses bumped in the magazine or melted plastic tips - too much caffeine and spicy food when I check for pulse in the scope - but I've always found loads that carried up just fine for my purposes with negligible effort.

I must be missing something so I'd like to know why the OP and the experts never suggested putting up paper in line at 100, 200 and 300 yards to check for group size at multiple ranges from the same shot string? Maybe even have a closer range aiming point and longer range paper target just in case the scope had parallax set for a rimfire or shot gun use - I've got a low power shotgun intended scope set for 75 yards - maybe I thought I could slip a bullet through a small opening in the brush? - mostly for kicking elk out of shady beds on the north face like whitetail in warm weather but the parallax setting is obvious when I move my head with the rifle on a rest? Shooting rim fire for score there are a lot of mechanical adjustments to keep a consistent cheek weld but shooting group at these distances I wouldn't expect any adjustments at all in the scope and let the group form where it may?

With all due respect, the OP has stated this information in his posts, to one of which you replied "OK."

John, I think he said it is a Nosler 48 rifle chambered in 7mm08. His handload was a 150gr. ELDX running about 2720 fps. The factory loads were Federal 140gr. NBT running around 2800 fps. An interesting part of his OP, is he states the loads he fired off had shown good accuracy "1.25" or better" on the first outing, but then states he tried them at 200 yards on a different day. I honestly don't think he is working with a good "proven" load. Things like a change in temperature can drastically effect the accuracy of a load, depending on how finicky the rifle is and what powder he's using. Again, he doesn't give specifics on the load. Hell, he doesn't even show pics of the groups. Now about the scopes he's using: The first scope he tried was a Leupold VX5HD (what power range, I don't know). Now it's a "Conquest" of which flavor no body knows. Does it have a parallax adjustment? Who knows. What power range? Who knows. I believe he's being very tight lipped. According to what he said, he doesn't want to "point fingers" if he ended up buying a "junk" rifle or scope. In his words, not mine. Like swifty said, Nosler has a 3 shot guarantee of 1 moa at 100 yards, with their ammo and probably their shooters. The rifle sounds sufficient enough to meet their accuracy requirements. I'm like you though, read enough of these kinds of threads and think to myself, send the damn thing to me. I'll shoot it and if it doesn't shoot well enough, a little tinkering like swifty said and it will be shooting lights out. A lot of these threads don't have enough information and getting that info from the op's seem more like pulling teeth, than anything else. I can see why you get tired of such threads as this one.. and some of these guys wonder why stick is so damn hard on them...

Posted this on 1/28. Be happy to provide more details and answer any questions if it helps solve this mystery.
The scope that I swapped to this week is a proven zeiss conquest 3-9x40 that I took off my daughter's rifle along with a new set of talleys.
Original scope was a 3-15x44. I promise I'm not trying to hide any details now and not trying to be vague, I'm the one asking for help and suggestions.


My range session today was cut short, but it appears the change in scope didn't help.
Wind today was again barely noticeable and pretty much straight at my back.
My range has dense woods on 3 sides, so wind has never been an issue.

I really appreciate all of the help and suggestions and I'm going to keep working on this as I have time.

What I actually said was that every load I tried was 1.25" or better at 100 yrds. The load I settled on after the first days testing has shot 3/4" or better at 100 every single time. And I realize that 4 or 5 groups don't really prove anything, but I feel like the rifle is showing good accuracy......probably better than I'm capable of on a regular basis. I'm just having a hard time understanding how a load that does good at 100 will be bad at 200?

country boy,

Thanks for reminding me of the specifics about the rifle, etc.

Some other people on this thread have also said that the two things they've seen open up groups at longer ranges are wind (especially), and to a certain extent scope parallax--though parallax normally has a far greater effect beyond 200 yards. In fact that was the very first response to your post. Do you know how to check for parallax?

I'm still doubtful about the wind, mostly because I've actually measured wind a lot. Most shooters have very little idea of wind velocity unless they do, and also don't understand how much it can affect bullet drift, even at relatively short ranges.

Combining a little parallax and wind drift can make a considerable difference, even at 200 yards.

You also mentioned that your groups at 200 were scattered side to side, while your brother's were more vertical. Somebody else mentioned a slightly canted reticle as a possibility, but this shouldn't affect group side IF the reticle is aligned with a vertical line on the target the same way for every shot. But if not, at 200 yards, tilting the rifle from shot to shot, even slightly, can make considerable difference. In fact it can make considerable difference even at 100 yards, especially with a relatively high-mounted scope. I have a buddy who was having enormous problems getting a new lightweight rifle to group accurately, and he eventually asked me to help. He'd mounted a scope with a pretty big objective, which required high mounts--and it turned out he was tilting the rifle a little, differently for each shot. I coached him some, and the problem went away.

You've also stated the rifle was rested on sandbags, front and rear. Was the same rest used both at 100 and 200? Did you check to make sure the front sling swivel stud was sufficiently in front of the bag to not bump it during recoil? Did you rest the forend on the same place every time? Some rifles can definitely be affected by forend placement.

Some relatively lightweight rifles can also be affected by the hardness of the front rest. Even sandbags can be compacted hard enough to affect groups after some shooting. With lighter-weight rifles I've found a folded towel over the front rest can make a big difference in group size, as was recently discussed on another thread.

I rarely get a chance to shoot at 200. When I do my guns/loads that deliver sub 1" loads almost always open up to closer to 3." I blame that on me. Your case is different. Your experience is that if you have a one inch gun at 100, then it's a two inch gun at 200. I would be inclined in this case to remove the shooter as a variable. I'd try one more scope (one with adjustable parallax if possible) if possible. It's a pita, but maybe remove a scope off of one of the guns that you get 2 inch 200 yard groups with. At that point I'd say you have eliminated the scope as a possibility. That leaves you with a gun that misbehaves.

You said it's lightly used. How often do we read here of someone who can't get a gun to behave and they "send it down the road?" You may have had a gun sent down your road. I hope you can get everything worked out. I will be following this thread with interest.

Yes MD I did, I also read several reviews which I suppose I could dig up again but they were with a M48 in 7-08 and they mirrored yours for accuracy @100 but stating the 200 were very disappointing seems the rifles would open up past 3”.

Am still trying to figure out how that happens, without outside factors being involved.

Quite a few shooters believe bullets "destabilize" as they get farther from the muzzle, but bullets actually become more stable at "normal" ranges as velocity decreases.

John, didn’t say the bullets destabilized. You have even stated that moving out to the 2-300 increases the error rate. My point has always been that the rifle may not like what the heck he’s feeding it. It may never shoot that bullet and maybe with a little tweak of the load it just might. Did this awhile back with a 700 BDL in 25.06 seeing if a 110 AB would shoot. The sighter was a known load that was used to foul the tube plus I had 6 rounds left over that had to go.
Target 1-5 were all the exact charge just altered the seating depth 5 thou for each except #5 which I altered 10 thou to a jump of 25. All were in the 1-1.5” range @ 100 except 1. Now while all would be minute of deer at 200, reasonably I can expect maybe at best 2.5 to 3” or more @ 200.



I did put one of those 1.5” group loads out to 200 and it looked like this. Still minute of deer, but damn ugly.

I'm sure others are trying to figure it out too. I know others have said that the bullet actually stabilizes the further away it gets from the muzzle. Maybe he should shoot at 4-500 yards. I never waste my time at 200. Seems pointless in a way, unless you are limited to that distance. Maybe he should return it to Nosler and tell them that is shoots "1/2 moa at 100 and 2 moa at 200" and see what they tell him.. As for the seller that sold the rifle to him: if the op is thinking the seller sold him "junk", I feel for that guy and is one of the reasons I don't like to sell rifles. You'll sell a rifle to someone that shoots like my buddy Troy and blame it on the rifle and seller. I know the op isn't blatantly doing this, but the finger is waving in that direction a little bit. I also don't know why the op is not posting pics of the rifle or targets. It may, in fact, be a simple thing like scope mounted way to fu cking high, where you have minimal or no cheek weld. We've all seen that, or at least I have, so many times especially here recently with the use of rails and schit where guys think they have to have that to shoot at unmeasurable distances. Far beyond what any sane hunter should be shooting at critters. Things have to be consistent in order to maintain accuracy. The further you shoot, the more consistent you have to be. Eyesight even comes into play, magnification on the scope and for damn sure a parallax adjustable scope (which the op is not using), sandbags or rests and even the ammo play a big part in keeping and maintaining that consistent accuracy. And of course, like John has pointed out numerous times, wind. Hell, I put up wind flags on my 100 yard target stands. I'll watch them, keep an eye on when the wind shifts and hope for a null around the time I pull the trigger. Sometimes around here, the wind is always howling and you take what you can get, but wind does play a huge role in bullet travel, especially the further the bullet gets away from that muzzle.

A canted scope only becomes an issue if one is twisting turrets or using hold over marks on the reticle for holdover/windage correction. And it still would not increase group size, just move it off POA. And then it would only be noticeable at extended distance.

Your #5 is more or less what I look for when developing loads. I'd also shoot multiples of each, just to confirm the load is acceptable and consistent. As a matter of fact, I'm heading out right now to check a Tikka superlite I've been messing around with. Need to confirm a load a buddy and I shot the other day:


Time to shoot some 10 shot groups now...

Confirming and proving doesn't mean it has to be done that same day either. However, you don't shoot 100 yards with an "unproven" load one day and then expect it to miraculously shoot sub moa at any distance on a different day either...

See OP, posting pics is easy.. Anyone can do it...

bsa,

Bryan Litz has been advertising to pay the expenses of anyone who has one of those "magic rifles" that shoot better at longer ranges for several years now, and has yet to find one. That's because there's no way bullets that start out shooting mediocre groups, whether at 100 or 200 yards, can somehow curve toward the aiming point at longer ranges. Bullets do become more stable as velocity drops, because there's less air pressure on the front end, while the spin-rate stays high, but that doesn't mean they have eyes.

There's also no way to build to build something into a rifle that makes it shoot larger MOA groups at 200 yards than it shoots at 100, as long as the rifling twist adequately stabilizes the bullet in the first place. So something other than the rifle itself has to be causing country boy's problem.

I totally agree my friend. You have been hitting the nail on the head with your posts. Keep these guys in line while I go and shoot my new Tikka....

Swifty,

I didn't say that claimed bullets "destabilize." I was pointing out that if a rifle groups well with certain loads at 100 yards (which is what country boy says) there's no physical reason the rifle itself will cause groups to open up at 200. So the answer has to lie elsewhere than the rifle itself.

A worn out barrel shows up first at longer ranges.

Well if we have eliminated rifle and scope, so I guess that only leaves 2 things, the load itself , the shooter or both.
As far as 10 shot groups, I basically have no need for them as I would rather put 20 shots inside the 10 ring on 10 different targets at the 2 or 20 into 4 different 10 rings at the 300 shooting a score match. Doing so means you have had to move your aim point to get to the next target, whether it be moveing up, down or side to side.

My trick to solve the cant problem, use a level when hanging targets. I have been known to snap a chalk line on the backer that is measured using a line level. That lets me lineup along the grid lines on a target. That has helped me at 100 and 200.
Wind is a factor that I can mitigate somewhat getting to the line at 8 on opening range time and usually calm until 10. On good days it might be ok until shortly after noon.
I never really knew about parallax until reading a short paragraph here years ago and bought a good AO scope, learned a lot from that exercise.

Just putting this out there, someone may learn something from it.

Or wind--or possibly inconsistent canting of the rifle.

I have seen a lot of people estimate a 5 mph wind at 2-3 mph.

I've been pretty quick to dismiss your suggestion of wind being the problem, but I hope you're right.

Not discounting wind at all. By his numbers if truly a head wind 3-5 it only drops .2” more @ the 200 than 0 wind.
I always have wind flags with me at the range, indispensable tool usually 1 @ 50, 100 and 175 so I can see 2 flags at both 100 and 200. Seen some weird things.
I wish I had a video of my 175 flag on one occasion light winds like his except measured. All was still, but while taking a break I watched the tails of that flag go straight up, then drop. Only thing that moved. Have a video of 2 flags in a 8-15 switch wind one at 50 and 75. The 50 was exactly the opposite of the 75, so I just shot through the middle where it was calm. 😳

I agree. As an engineer, I have a pretty good understanding of physics and ballistics and nothing about this makes sense.

MD, Thanks for all of these suggestions. This is exactly the kind of information and recommendations I've been looking for. I appreciate constructive criticism without treating people like they are an idiot, as I have seen so often by others. I think I would almost rather find out that I'm the culprit than it be a rifle or scope problem......

During my next range trip, I will pay particular attention to the sling studs placement, both front and back. I will also check the wind more closely. I spent a great deal of time checking the original scope (VX5) for parallax and playing with the adjustments, but could not see any problems as it was set. Both scopes have the adjustable ring on the eyepiece.

One also needs to understand that statistically he must shoot a substantial number of groups at the differing ranges to accurately know what the rifle is actually doing.

I truly believe my statement that far more 1/2" groups are fired on the internet than ever fired on the practice range

It's been a long time since I've taken classes on statistics but can assure you that to say "my rifle shoots 1/2 MOA" requires a lot of shooting to support that statement....to say that it shoots different than 1/2 MOA at greater distances requires a lot more shooting.

Can you do this?.....place two targets at 100 and 200 yards distance and one precisely behind the other such that one only has to shoot through paper at 100 yards and therefore can measure the very same (10-shot) group at both ranges.....

This should prove the theory that the MOA is different at different ranges....or possibly disprove it.....I won't speculate!

MD, on that dare of a load that shoots great @ 2-300 but won’t shoot at 100. Does this fit. Shots 1-3 grouped well shot 4 just out, shot 5 keyholed.



Or should I quantify by saying 4&5 actually hit the prop on my 50 yard flag spinning at 15 mph. 😁

nbt locations near me

Just kidding.

That one is for focussing the reticle. It is not the one for parallax (which is to say, bringing the target into the same focal plane as the reticle).

I agreed with this 100% and maybe my original post title was misleading.



I think I can rig that up. Should be interesting.

Correct. And that was my first move. I made sure the reticle was focused and checked for any apparent parallax issues, but did not see any.

Swifty,

HA!

country boy,

How did you check parallax?

I had another thought, but need to ask another question: Have you shot other rifles on the same range at 100 and 200 yards?

I think I can rig that up. Should be interesting.
[/quote]

I could be wrong but it seems that bullets hitting even a piece of paper at high speed could cause them to deflect a little, opening up the group at 200. Just guessing.

As to the initial question, it's because they are fickle damned things.

JayJunem,

I believe Bryan Litz uses electronic targets when testing relative group size at different ranges, for that very reason.

Horizontal spread could indicate an issue with the rear bag.

I placed the rifle securely on the bags, aligned the scope to my target, and slowly moved my head in various directions to look for apparent reticle shift. I did this with my 100 yd target and my 200 yd and could not see any.

yes. Many times. With several different rifles. Usually after I get a load that I like at 100, I go to 200 to confirm and zero and then practice out to 400.

Definitely going to check into that. MD said something earlier about the sling studs and I'm pretty sure my rear sling stud was on my rear bag, so I'm going to change my setup next time out.

That right there explains it. I always remove them for load development.

That's interesting.

I know nothing about electronic targets. I'll have to Google that.

I hope you're right. Easy fix.

There is truth in this statement. As we put more rounds on a barrel, we usually see a drop in X counts at 600 yards as the first sign it is nearing it's end. Scores will drop next and flyers will appear at the short lines (200 and 300 yards) more frequently. It's not uncommon that while this is going on, the barrel will continue to pump X's on a 100 yard reduced target. The more frugal amongst us will turn that barrel/upper into a "reduced course only" upper. The no-nonsense folk pull the barrel at the first hint of a drop in performance and add a tomato stake to the garden.

My learning is to always check your accuracy at the maximum distance your shots matter at.

A whole lot of energy has been spent here, mostly constructively. Several have pointed out some very good points.

PaulBarnard's post to the efect of "change the shooter" is probably the best.

Next week I get new lenses in both eyes and going blind has shown me more than a few things... double entendre intended.

Carefully focusing the reticle is critical and sizing the target for the scope and power at the specific range is critical. Making a very hard black square on a very white background such that the reticle is placed against said high-contrast corner will allow the blind to see again! Just a few days ago I had to go to the local range, which I absolutely dread. Friend could not manage minute-of-moose. Simply making him use the center of his finger pad made his shooting go from ridiculous to repeatable.

Power changes should not cause a problem for accuracy, but may cause a change in hold because the increase in power shortens eye relief which forces a change in hold. Without the change, the P word...

Another variable I have seen many times involves rapidly changing weather both at ground level and at elevation. Rapidly moving clouds toss shadows and hot spots all over the place and force the eye into contortions trying to keep up.

If the op failed to see any parallax maybe he should look again...

Sizing the target to the scope is often a lot bigger issue than many realize.

Forgot to add the old eye sight test of the ancients. Redundancy not intended...

Mizar and Alcor are a couple stars in the Big Dipper and if you can see them as two stars your eyesight is at least 20-20, or so they say. Point being it is hard to meter everyone's eyes in a crowd, Best to look at what one's own eyes can do and maximize the potential.

I could be wrong but it seems that bullets hitting even a piece of paper at high speed could cause them to deflect a little, opening up the group at 200. Just guessing.
[/quote]

Maybe set up a first target at 100yds with two aiming points, one right on the center of the paper and another right on the upper edge of paper and the rifle sighted in 2" high. With a paper at 200 hundred right behind the first one, but taller in order to cath the bullets aimed at the higher bullseye. Like that those bullets would fly high over the first target and not having to go through the paper it will not deflect at 200. And see how the groups compare to those that go through the first paper.

I think it is going to be a very interesting experiment I`d love to do it myself nut unfortunately I don`t have an appropiate place to do it. Please keep us updated with your findings.

Thank you

chamois

When I had discussed the opposite situation (smaller observed MOA groups at longer distance than at shorter) with Bill Davis Jr in the pre-acoustic target days, he suggested shooting through onion paper at shorter range to avoid altering the downrange path.

Franklin Mann in his 1909 book "The Bullets Flight from Powder to Target, used this method to document bullet's paths as they travelled down range.

Today you can use acoustic targets that triangulate the bullets position as it passes through the target plane without having to touch paper. Here's one example.
https://oehler-research.com/system-86-acoustic-target/

My scopes aren't adjustable for parallax, and the Leupold ones are nominally set to be parallax free at 150 yds. Is there a theoretical or practical maximum parallax error at 100 & 200 yds.?

Maybe set up a first target at 100yds with two aiming points, one right on the center of the paper and another right on the upper edge of paper and the rifle sighted in 2" high. With a paper at 200 hundred right behind the first one, but taller in order to cath the bullets aimed at the higher bullseye. Like that those bullets would fly high over the first target and not having to go through the paper it will not deflect at 200. And see how the groups compare to those that go through the first paper.

I think it is going to be a very interesting experiment I`d love to do it myself nut unfortunately I don`t have an appropiate place to do it. Please keep us updated with your findings.

Thank you

chamois
[/quote]


This has already been done decades ago with onion paper.

[quote=jwp475

This has already been done decades ago with onion paper.

[quote=jwp475]


Depending on how many decades, maybe none of us was born by then...

If you don't mind ilustrating us with the results...

Did the (angular) grouping change with the distance?

Fortunately Dr. Mann’s book is still available. Should really be required reading.

There are a bunch of books, both old and new, that should be required reading--if that means acquiring an understanding of what actually happens when a rifle goes bang, and how much riflery has advanced (or even repeated itself) over the decades, and how many of the "common beliefs" many shooters still have are mistaken, though they may have been at least partly true in the past. Bryan Litz's books should also be "required reading."

MD,
Agree, but at what point with all the advances do we eliminate the old adage of tuning the load to the rifle to a more appropriate term of tuning the rifle to the shooter? Not trying to be PC, Valid question. Have seen more than once where the rifle was better than the driver.

That's always the basic conflict.

I should have added: especially in 24hour Campfire questions about: "What's going on with my damn rifle?"

Easy, the nut behind the butt. Next question.

Yes. the maximum parallax error E at a given target distance t for a scope which is parallax-free at distance p and has an objective lens diameter D is given by the equation

E = 0.5 D (abs(t-p))/p

So, for example, if you have a scope with a 40 mm objective lens, parallax free at 150 yards, maximum parallax error at 200 is

E= 0.5x40 (abs(200-150))/150

=6 2/3 mm

Similarly, for a target at 100

E= 0.5x40 (abs(100-150))/150

=6 2/3 mm

That is to say, if your eye position is at the edge of the exit pupil, you could be as much as 6 2/3 mm off at these distances, in these particular examples.

Dan,

Yep, exactly--but there are many assumptions in parallax calculations, especially that the shooter can recognize it. Many don't. Country boy only states that he adjusted the rear focus on the scopes, which may indicate he doesn't know how to check for parallax. I asked him specifically about that at one point, but he never really responded.

Unless I missed some other details (this thread has gone on for a long time) he wrote he used a "Leupold 5HD" and a "Conquest" scope. He does not specify the magnification or objective lens size of either, so there could be far more parallax than you're assuming, especially assuming a scope parallax-free at 150 yards.

Add a little wind-drift to more parallax than the possibility you used as an example, and there could easily be 2+ inches of error at 200 yards.

I was answering Youper's question, not country boy's, in that post.

FWIW though I raised the question with country boy earlier about adjusting the eyepiece focus rather than parallax, and he confirmed that he was both aware of the difference between eyepiece focus and parallax adjustment, and that he had adjusted for parallax.



I made the point earlier that I didn't think that parallax was the sole problem, if it was the problem at all. There are a range of other possibilities, including wind, and including the possibility that a number of issues, perhaps including parallax, are combining to produce the observed result.

Dan,

What he posted was, "I made sure the reticle was focused and checked for any apparent parallax issues, but did not see any." He did not state whether he did this at both 100 and 200 yards. A lot of shooters assume that once the reticle's in focus, there is no parallax.

He has also never stated the magnification, objective lens diameter, etc. of either scope. All of which would have some bearing in the question, even if the reticle's in focus. Have seen considerable parallax with a 5-15x German scope at 200 yards when set on 15x and the reticle's in focus.

And the graduations on the parrallax adjustment don't seem to always align correctly with the actual distance.

I have several high end scopes I shoot with. I start adjusting to eliminate parallax error at the yardage I am shooting. When the target is brought into sharp focus using the parallax adjustment I know two things:

1. I am close, but there is still parallax error; I can induce it by moving my eye that is peering through the ocular and watch the reticle move around on the target although the rifle and scope are not moving...only the position of my eye relative to what part of the ocular lens I am looking through. I need to continue to adjust the parallax knob.

2. The final image, as near parallax free as I can get it, is, for me, always slightly blurred. Could be my eyes...I require corrective lenses to see "20/20".

I thought I had added this info, but I can't even keep up with this thread now.
The first scope was a leupold vx5 3-15x44. It has a side focus knob and an eyepiece adjustment ring.
The 2nd scope is a Zeiss Conquest 3-9x40. It only has the eyepiece adjustment ring.
I checked for parallax at 100 and 200 with the vx5 and found none. I did not check the zeiss as it has been excellent on another rifle for several yrs, but I will check it on my next range trip. I shot both scopes on maximum power.

Country boy,

Yes, this thread has gone on a long time. I missed where you described how you checked for parallax at both 100 and 200.

I'm coming to the conclusion that the rifle is possessed by demons. Haven't seen many rifles that are, but there have been a few over the years....

Have also come to the conclusion that I need to quit responding to any "Why doesn't my rifle shoot?" threads if they go on more than a maybe 20-30 other responses. Apparently beyond that point I don't care enough anymore to carefully recheck every response.

In fairness to you MD, this is actually the second thread on the issue, after some static from one of the contributors in its first outing. It is a good example though of how if a "why doesn't my rifle shoot" goes on for very long things get repeated, issues that were dealt with come up again, and it can be hard for anyone to keep track of where we're up to.

Thanks, Dan. That clears some things up. But I have often found "why doesn't my rifle shoot" threads to be something like chasing invisible rats down an endless hole.

All too often there's something really simple wrong with the rifle--though not always obvious. Earlier I mentioned a question from a member on a good load for 165's from a .30-06. I gave him my standard answer, around 58 grains of H4350, but it didn't shoot, even after he changed scopes. Six months later he contacted me, and it turned out he'd tried two brand-new scopes. Both were bad. With an old proven scope the rifle shot under an inch.

Another time went through a bunch of stuff with a question about a custom rifle that didn't shoot. After quite a few posts, from the OP and me and others, it turned out he hadn't tightened the scope bases down.

I find it easier to glass bed, freefloat, fine tune a trigger and work up a good load that easily shoots moa, than it is to follow some of these threads. This one was funny because the OP seemed to be tight lipped about a lot of things. You basically had to beat the info out of him, with repetitive questions. He's yet to post any pics too (like I asked for multiple times). A lot of these guys are here to help, but when the op has to be asked 5 times what kind of scope or how its mounted, it kind of gets tiring...For example, finally on page 12 of this thread, he finally tells us the scope is a VX5 3-15x44. Before that, it was just a "VX5". From that info, we know it's a parallax adjustable scope and generally of good quality. However, it's still not a "proven" rifle scope. If these guys would just take a little time and establish a rock solid foundation (glass bedding), tune the trigger, sufficiently freefloat their barrels, USE a PROVEN rifle scope, ensure their ammo is concentric and work up a good accurate moa load, there would be far far less of these threads. However, some guys think they can just take a bone stock rifle out of the box, have a store clerk mount a scope for them and be shooting lights out at the range that same day with factory ammo. That rarely happens, and for how long is it going to keep doing it? Who knows: Did the store clerk use loctite on the base screws or even torque them down properly. Did he make sure the base screws were of the appropriate length? Personally, I still believe the OP's "1/2 moa" rifle has not even proven to me it's a moa rifle at 100 yards. I'd need to see many many multiple 10 shot groups to verify it's a moa capable rifle. Even if it's only shot at 100 yards. Shoot some 10 shot moa groups at 100 yards and I'll guarantee its going to shoot well at 200, 300,400, etc. etc.. I've done it thousands of times, to know it's going to happen that way.. The secret is knowing you have a proven and capable set-up. You don't just fire off a couple 3, 4 or 5 shot groups that are 3/4" to 1 1/4" and say, ok, it's an MOA rifle now. Show me multiple targets, make me a believer. This just hasn't happened yet in this thread...

MD, regardless of how this turns out, I've learned a lot from this thread. Thanks for your assistance. I hope to shoot again this weekend and I hope I have plenty of time so I can work through some of the suggestions. My thought from the very beginning was that the problem was the scope or the trigger puller. I'm starting to think it's the latter......

Thanks again.

You're welcome. Will still be very interested in hearing how it turned out--especially if the rifle's not possessed by demons!

BSA, my apologies for asking for help prior to shooting at least 1000 rounds. I'll wait a little longer next time I have a question.
Yes, my post was initially vague on purpose because I was looking for generic answers and I didn't want people jumping to conclusions based on brand names that don't have a good reputation, etc. I also wanted to protect the individuals that I bought the rifle and scope from. I'm not blaming them for anything and I hope others don't either. I see now that was the wrong approach.

Yes, my first thread in the hunting rifles forum was derailed by a jacka$$, and I copied my post to here where most people have been helpful, even if a little condescending.
I haven't posted pics cause I didn't take any. I made notes and moved on. Maybe I should from now on.
I didn't post all the details because I didn't know what was relevant. As I said, I've learned a lot here.
Also, I mounted the scopes myself. Never have or will let a "store clerk" mount a scope for me.

Thanks. So it sounds like the maximum in this example that parallax alone could add to a group at 100 or 200 yds. is about 1/2".

Plus or minis 1/2”, so maximum possible error between multiple shots in a group would be 1”. And that depends on the true parallax-free distance (which may not be as advertised), and the size of objective lens.

(6-2/3 mm x 2)/25.4 = 0.525"

What am I missing that would double the size again?

Nothing. You’re right. For some reason I equated ~6.5mm to 1/2” in my head...

Me thinks country boy is a pretty sharp Dude and maybe sharper than you think ! My 243 Hawkeye does it too and I believe after reading this thread it could be 69 years and NOT holding !Shoot quick and killum dead Country Boy

Update:

Between the crappy weather and work and family obligations, I haven't been able to shoot in over 3 weeks, but I finally caught a break this morning and made a run to the farm.
Since my last range session, I've cleaned the barrel, checked the action screws, checked the scope mounts and carefully loaded some more ammo. When I set up to shoot today, I paid close attention to the wind and changed how I placed the rifle on my sand bags. I'm not sure which of these thing(s) was the problem, but apparently I fixed something!!!!!

The first 3-shot group at 200 yd was just over 1.25" with a 140 accubond handload. I followed that up with a 2" group with a different handload (150 ELDX) and then a 5 shot group with factory ammo of 1.75", all at 200 yards.
After that, the wind picked up and I headed back to work, but I'm really happy that I seem to be on the right track with this rifle. I hope to get back out Sunday afternoon for another shooting session if the weather allows. Either that or I'm going to start building an ark....

Thanks to all of you that offered good advice. I definitely learned a lot here. I'm not going to win any bench rest competitions anytime soon, but at least I have confidence in this rifle and can move forward with load development and practice.

If I had to place a bet right now, I'm going to say that the sling studs or something about my rear bag placement was the problem. I used to shoot better groups 10 years ago without even using a rear bag than what I was seeing with this gun last month.

Nice it’s working for you. Doubt you really fixed anything but rather discovered that small things at the bench can make big changes down range. Also I have never found a sling or swivel stud that sandbags ever liked.

Congrats. The cloud is gone.

Happy shootin ....

Jerry

Well done!