Home Forums Hunting & Shooting AR and Tactical Rifles 1st shot out of group with RR Predator Pursuit

My RR throws the first shot about one inch from the remainder of the group. I've added a sixth shot that always stays within the 1 MOA or less group. I've shot about twelve groups with at least three different loads with both 60 and 77gr bullets. Most groups shot from the a hot barrel; all with the same magazine.


Will a taper crimp help? Any other suggestions?

you could try seeing if the scope has parallax in it at 100 yards, could be your first shot is off due to where your eye is relative to the ocular. Then shoot a 5 shot group single loading followed by a 5 shot group from the magazine, see if you have two groups. I would clean the chamber first.

Frankly my solution in the past to this problem is to sell the rifle if you get two groups from single loading and magazine loading.. I am not smart enough nor have time enough to fight something like that....

Does it happen only with the first group? How many shots are you firing into the group? It may be you getting settled in behind the rifle. I know nobody wants to consider that possibility but I went through the same thing only to find out it was a shooter problem.

No matter how my ammo is loaded into the chamber, the COAL does not change. I have to chamber the same round 3-5 times from a magazine to get the bullet to budge and it actually moves forward just a few thousandths. Measure your neck tension to be sure but as long as you are getting .002"-.003" you should be fine without a crimp.

Before you sell the rifle... and after you've seen if its you or the gun, is 1 inch out, enough to matter for what you are doing?

According to Formidilosus, your gun is broke, Sorry.

Are we talking 1st shot and cold barrel or every time you shoot a group?

Thanks: all good points. I haven't checked for parallax but will first chance. For me, parallax problems give randomly large groups with inconsistent fliers at various points. The RR always throws the wide shot on the first shot hot or cold. Does the same almost every group including some shot by an experienced competition shooter friend.

Also, I will try shooting groups single loading as a test, and I will give the chamber an extra good cleaning.

Wont be selling the rifle. This is my first AR and working out accuracy problems is part of the fun for me. My purposes is PD shooting and possibly local matches.

More tips and suggestions will be appreciated.

I wish I had suggestions...

Other than a new barrel.

if you get two groups from single loading and then magazine fed, maybe replace the barrel. I had a bushwacker once, bought during one of the panics.. the rear sight had to be screwed to one side to get the rounds on paper at 50 yards, I figure they just built a POS and shipped it, that one lasted a month IIRC.

I wish I could be positive and blow rainbow smoke but at my age, I just relate my personal experience as it was.

Try loading a magazine full, putting up multiple targets and shooting two groups without unloading. It could be the difference between dropping the bolt from the catch and having it cycle normally. Sone handguns will do the same.

Yes, it can be related to the difference in how the bolt chambers a round.

But WHAT do you do to solve that issue?

Stronger buffer spring?
swap out the bolt?
Heavy palm on the forward assist with the first round?

I'm also wondering about the quality of the stress relieving of the barrel.....and there is only one way to fix that.....new barrel.

Never heard of those solving the problem but I'll damn sure try to put that in the back of my head in case anyone around here runs into it.

I coudl see the FA thing, I could realize the spring might help. Not sure how swapping the bolt could, BUT I don't discount suggestions. Glad I"ve never had the problem. Most likely don't quite see that in top line barrels I'd bet.

I to suspect cryo could help, but cost of that vs cost of the tube and not knowing if it would fix or not......

Now if I could just get back to working out the 1 and 2 groups from my 7x300..... always one flier in 3 shot work up groups... never consistent when... but talking bolt gun now and way OT...

Yea Rost, I'm not sure any of those idea's would work, but if there was something different in the lockup between the first and remaining rounds, even if it was very slight, I can see how it might change the POI.

Since the spring moves everything into battery, and the bolt does the actual locking, I was just considering them as outside possibilities.

Since springs and bolts are good parts to have on hand, and cheaper then a barrel, they are just something I would consider trying, but if I was a betting man, I have to go with an improperly stress relieved barrel.

Shooter problem; gun doesn't know how to count or when groups start or stop.

MM

I am thinking the problem is likely the first round chambering softer than those during gas powered cycling. Single loading some groups may tell me something. A good push on the forward assist is worth trying. A call to Rock River is next.

It's probably not a stress relief problem because it does the same thing hot or cold or shooting fast or slow. If this barrel was on a bolt action it would probably be very accurate.

Montana Man, rifles can't count, but they react to differences in bullet pull, vibrations, cartridge concentricacy, and various other mechanical dynamics.

You might be onto something there. Is the BCG locked open when you insert the loaded mags or are you using the charging handle? It might help to vary your technique a little. Just a SWAG on my part.

Have you measured the rounds before and after loading to see if there is any change in the COAL?

seeing if it shoots two groups with single loading and mag loading gives you a damn good story to tell bushwacker and put targets in the box when its going back.

next randomly generated thought...what buffer in the gun? Go to the next one up, H1, H2 or H3...

edited to add...

I once bought a demo Conquest scope when they were a newer product. I had 3 of the 2.5-8's at one time. On a nice Kimber .257 Roberts the gun was producing two groups at 100 yards, over and over again! I was pulling my hair out with loads, technique, different bags until one day I noticed that where my eye went made the crosshairs move a bit at 100 yards....Zeiss told me the parralax had been set for a muzzle loader, not sure if this is correct but what they told me, the rifle was fixed when I remounted it and tried again.

but if you have had a sniper shoot it well then its just the gun...

part of the parallax problem is that folks think scopes are foolproof.

I center everything even with a scope, probably a habit from shooting irons so many years, but I digress.

Sending it back to bushy because the first round is only an inch out won't generally get you anywhere..

I sent a TC barrel back once, it was shooting 4 inches at 100... they shot a 5 inch group and sent it back saying it was acceptable... so I bought a new barrel for the gun. Renegade 54. Factories don't much care about tiny groups generally speaking

too true, no vender really cares how the gun shoots as long as it goes bang.

The top line builders will. But typical vendors, unless its horrible, will tell you its within THEIR specs....

Maybe try loading 10 in a mag, drop bolt, shoot, lock back and eject next, drop bolt and shoot, repeat for 5 rd group and examine ones you ejected. Might just need to polish feed ramps.

Eagle; you, TC1 and jimmyp all have good simple easy to do diagnostics. I'll add them to my list of tricks to try next range session. I don't want to send the rifle to RR if a simple fix with no smithing will work.

How are you closing the bolt on the first round? Bolt release, Full pull on the CH, or slow release on the CH?

let us know if you get two groups from single loading and mag fed, I am very curious.

Grand, I have been using the bolt release with five rounds in the magazine. I plan to test all three methods on the next range trip, will post results.

jimmyp, also next range trip. I am curious myself.

Possibly going to the range Wed. 8/12, more likely next week. Our frequent high variable winds make careful testing difficult, but we do get some good shooting days and I will report as soon as possible.

THANKS FOR YOUR INTEREST AND HELP!

JIM

You have a sloppily chambered barrel.

Your bolt has too much over run. Basically, when it runs forward to chamber the round, it is sizing the case down, effectively increasing headspace for that round.

The only cure is a new, properly chambered barrel. There shouldn't be more than about 2 thou of clearance between the bolt and the barrel face when the bolt is firmly seated back against the barrel extension lugs.

Sorry about your luck.

So, how do the next rounds going into battery not be effected by same slop? I"d think, that would equate to just generally larger groups like you get out of rack hunting rifles and such.

I would think if he used the bolt release to slam the thing shut the results would be the same as a second shot?

After reading OP, does it do it only with handloads, or factory ammo too? Perhaps greater momentum of gas cycling is pulling bullets and seating them into lands, or contact with feed ramp is pushing them into case? How is your neck tension? I use Lee factory crimp on my cerchunkers, don't bother on the bolt gun.

I'm just curious to Barrys thoughts? I have no clue, he may be onto something and maybe not.

I"m certainly far from the best person to diagnose this, but I have theories that have proven themselves on other similar things.

Me, I think its the way the first round is loaded personally... though it never made a difference on my good guns, but I never knew what would happen the other way around.

It's a pretty well documented phenomena that any accuracy-minded auto rifle smith would know about. I guarantee Holliger & Frank White carefully control for this when they do a barrel. But when factories do them, all they do is screw on an extension and run a reamer in until a bolt closes on a Go.

Bigger rifles are more susceptible to it due to the increased mass of their bolts.

Pulling the bolt back and letting it fly (slingshotting) generates more energy than the automatic functioning of the rifle.

The OP can check this out with a Hornady Headspace gauge. http://www.hornady.com/store/Lock-N-Load-Headspace-Kit-With-Body-1-Each/

Use the gauge to measure the headspace length of a couple unfired cartridges. Next, slingshot them into the chamber and re-measure. Note the new numbers. Ideally, it shouldn't change or be more than a thou, maybe 2, different. You gotta have some clearance in the fit to allow for function and this is one reason why automatics will never equal bolt actions in accuracy.

Then do the same thing with a few more cartridges, only this time feed them out of a magazine by firing a round to chamber them. Don't shoot them, take them out and measure them, comparing the numbers to the new, unchambered and the slingshot fed.

It probably won't do a whole lot of good to single load every cartridge when shooting for groups. The loose headspace produced by single loading doesn't help accuracy.

To see if you are right, then we should load 6 rounds in a mag, load one by hand, fire it into the dirt, then group the next 5.

I hear you on good smiths being precise, but thats waht we pay them for.

I am not a smith by any means and was not aware that the slop in the chamber would make that much difference just on how a manually chambered and fired chambered round would group, to be so repeatable as to do it every last time.

Lets see how the 6 round test works and should answer your theory then.

jimone, one group was with factory ammo with the same results. However, it was American Eagle 50gr. tipped and may not have been crimped. In intend to try both crimped and uncrimped versions of the same load. I am thinking the bolt slam may be harder from the bolt release than during normal cycle. I will consider a lighter mainspring or heavier buffer.

I don't think I have a head space problem; the cases show no sign of insipient separation or other signs of problems. If I check the head space and it is excessive the upper goes back to Rock River.

You can have correct headspace and still have a bolt overrun problem.

is this one of the guns that RR guarantee's One MOA with 3 shots? If so send it back to them. If not buy a new barrel.

Seating the bullets out to near max and taper crimping seem to have fixed the first round problem.

I am with Jeff, cryo sure would not hurt. Cryo has the ability to relieve stress, and it sounds like the barrel is stressed and once it gets a little heat it settles down.

I thought the same thing until he confirmed that it did the same thing, hot or cold. Now that he says crimping has fixed the issue I doubt it was a stress related problem.

Yep, that makes sense.

Crimping might not have even been the whole issue, it might be related to the load being just on the edge of going nuts, and not in a a harmonic sweet spot, that either say half a grain or a full grain eithe rway would have had the same results.

Yeah, I agree.

I'm still wondering if the 1st round were chambered from a locked back bolt instead of the charging handle if that would make a difference also with uncrimped bullets? Just something that upsets the first round like all of the rest that get fired in the group. I dunno, it's just a SWAG on my part though.

Sometimes it's the little things that will frustrate the hell out of us. Most of the time it's my ability and not the rifle!

IMHO hot or cold, doesn't matter that much, stress is stress.

You have it solved now, but you could have the barrel relieved and go back to non crimped and it could have also solved the problem.

Or not.

I had a GAP 10 and was getting lousy groups from 175g FGGM. At one point during my shooting session, I pulled a loaded round from the chamber and pulled the bullet out of the case in the process. The inertia from the bolt closure had moved the bullet forward into the barrel where it became stuck. (Just like a kinetic pullet puller.) For whatever reason, I had a batch of FGGM with inconsistent neck tension and was getting inconsistent COAL during chambering.

Solution: Once the gas system has been tuned, the solution is to crimp or increase neck tension.