Home Forums Hunting & Shooting Long Range Hunting Ladder test, How, why?

Rost,

This is starting to make a lot more sense in terms of validating the ladder method. So you run a broad sweep of the charges with single-shot samples, find a node, then zoom-in with 3-shot groups of the charges that are in the node. 7mmDave seems to do something similar.

This seems a heck of a lot better than running a broad sweep of the charges, finding a node based on single samples, then picking one load. This is like trying to tune the station with just the coarse knob. By adding the 3-shot phase to your ladder you add samples to the test, but only in the area you think there is accuracy (fine tune) as opposed to a 2-3 shot ladder. But, you could still miss a node during the single-sample phase due to shooter error, etc. correct? The upside is that any "false" nodes are detected and rejected by the 3-shot groups.

I still see merit in finding pressure/velocity quickly by starting very low, and working up. The steps up might be fairly quick so I don't think the ladder provides much value (i.e. shot from the hip if desired), plus I don't care if there is a node that is 200fps below my target velocity. But I still like to begin low, with published start charges. Once pressure/velocity is found, I could see the value of shooting a ladder with tight steps over a 100-150fps window around my target velocity. At this point, the fine tuning phase, there isn't too much difference between the tight mini-ladder vs shooting groups & looking for low SD/ES. The mini-ladder will require another round of 3-5 shot groups but covers the 150fps window quick.

Jason

rost495, Jordan, and Boxer,

I'd like hear your thoughts on SD and ES in terms of developing an accurate load. I know SD and ES were mentioned earlier in terms of significant sample size but what have been your observations? I also recall some people stating that low SD and ES are not necessary for best accuracy. Mebbe I read that wrong because it don't make sense due to TOF, gravity, etc. If all things are equal, a slower bullet can't hit the same spot as a faster one. There needs to be another variable(s) that makes the shooter "think" it does.

I know Litz has written about this,

"...you can see that reducing muzzle velocity variation from 20 fps Standard Deviation (SD) to 10 fps SD improves hit percentage on a 5" circle at 500 yards from 83% to 93%."

83% to 93% per Litz is nothing to take lightly. It seems that the original KFPRO to find accuracy is based on low SD, which is supported by Litz.

More from Litz... LINK

Two things- long range accuracy is hard to accomplish with high SD and ES figures, but you don't necessarily need the lowest SD and ES to achieve best accuracy at distance.

When the bullet exits the barrel during the top of the muzzle's elliptical upswing, velocity variation is mitigated to some extent, as JBurns and rcamuglia pointed out. Faster bullets leave the muzzle sooner, while the muzzle is pointed lower at the target, while slower bullets leave the muzzle later, when the barrel is pointed higher on the target.

So while low SD and ES numbers are always a good thing, there are other factors that can reduce their significance, or even take precedence altogether.

The kiss gives mechanical advantage, and loading to top pressures gives physical advantage. Hint.

The target that I posted above of 5 hits (the screen shot on the app says 4 shots) at 1762 yards with nearly no vertical, was shot using a load with an SD value well above 10, just for conversation...

You really haven't been paying attention whatsoever.

First, the fact that loads in the node are always tested with group shooting has been stated many times in this thread by everyone who shoots an Audette. How you just picked up on it in Rost's post now in this 79 page thread is amazing


Secondly, the FACT that a lower velocity load can land at the same spot as a faster velocity load has been covered as well. It's called Barrel Harmonics.

If the bullet exit times are during the UPSWING of the barrel, the faster velocity loads exit EARLIER when the barrel is pointing LOWER AT THE TARGET, AND DROP LESS UPON REACHING THE TARGET

The slower velocity loads exit LATER during the swing when the barrel is pointing HIGHER ON THE TARGET, BUT DROP MORE UPON REACHING THE TARGET.

This counteracting combination makes all of the projectiles land as close to the same horizontal plane as possible; NO VERTICAL DISPERSION.





Believe me, I had to read this many times over to really understand it. I think it's because my crossed eyes and drooling yap interfered with my pretend and imagination the entire time my [bleep] was gripping the couch preventing me from going full bore by kissing, finding pressure, and rocking.

Either that, or it was my poor, poor, whining that confused my dumbfuckitude and blessed my heart under my paper hat.

Could have been the Smoke during the Ladder that burned my eyes though.

All of the above??

Rick,

I thought you were done trying to convince anyone to buy a ladder?! What happened? Feel left out?

So, you do what Rost does? You use 3-shot groups for EACH CHARGE in the node? Did you mention that anywhere in this thread? If so I apologize.

Please quote or link where you validated the wide sweep, single-shot sample with groups for all charges in the node, as Rost does. Pics would be even better.

This isn't the same as picking the middle charge of the node and shooting a group...

I'll comment on Al in a bit.

Jason

I have a box of 7mm 168g Berger classic hunting bullets.
Thats what it says on the box.
Berger classics look an awful lot like SMKs to me,and do not resemble VLDs or Hybrids at all.
Really dont know what you mean by saying, "Berger Classic Hunters (hybrid design)."
VLDs are noted for shooting in the lands.
But if you start out that way where are you 500 rounds later?
Also,Lets say you run hard in the lands...your in a match and the rangemaster,for what ever reason, calls a "cease fire remove your bolts..."
And there you are with a bullet stuck in the lands and powder stuck to all the lube inside your action.
And since this is the long range hunting board.
Lets say for some reason you unload your rifle in the middle of nowhere and end up with a VLD stuck in the lands 10 miles from the nearest cleaning rod.....
I have had VLDs shoot very well for me from time to time.
But there a PIA to keep working just from a seating depth point of view.Not to mention what a nice BR action looks like with ball powder stuck all over the inside of it....
I pass on VLDs these days.
Mr. Litz.
Just about the brightest guy in any room talking loads and seating depths.
Says to start the Hybrids at .03 off the lands.
Hybrids and VLDs require a different seating stem than conventional bullets.
You dont have to use a VLD/Hybrid stem.
But the loaded rounds have less runout if you do.


dave

The goo goo dad dad talk, does not become you.
dave

And Rick,

If you're still selling and haven't taken your ladders home , you could really hit a home run with pics of a 3-shot ladder (i.e. 3-shots for each charge weight) to prove repeatability. 5-shot ladder would be even mo better but these multi-shot ladders are rare around these parts ! Gotta admit that it raises the skeptic-meter a touch. Scratch that, it raises it a bunch.

Maybe you posted a 3-shot or 5-shot ladder already? I've been trying to pay attention, but the only multi-shot ladder I recall was on Page-1 and it looks like it reads "no wind" with a bunch of horizontal for identical charges! Guess I am missing something because the Ladder Gang started diagnosing the "node" without paying attention to the above

...(I'm wondering where the horizontal came from when there was no wind?)...

I know it wasn't your ladder, but at least someone posted pics of a multi-shot.

Jason

Jason,

I couldn't care any less what anyone uses for their load development as long as they're happy with the results they get.

Many people are very pleased with food from McDonald's

As I've said many times before, I prefer that anyone I shoot against in a rifle match use something other than the Creighton Audette Method to find their load.

I've posted in this thread that once the node is found, I shoot groups with all of the loads that are obviously in the node to find the one that groups the best. With that load, a seating depth test is done if it even needs one. Pics have been posted. Go back and look.

Rick,

I owe you an apology, as I remember those pics now. But, were those shot at your standard ladder distance? You shoot your ladders at 400-600 yards? I'm assuming that Rost is shooting his 3-shot groups (the charges in the node) at the same distance as the ladder.

The key to this is that the ladder is validated. 100 yard groups may be ok to test loads, but it doesn't help validate the method which is what I've been asking for. Shooting 3-shot or 5-shot groups at the same distance the ladder is tested would provide more insight. I think this is what Rost and 7mmDave do and why its different than the other ladders I've seen so far.

Jason

You'd do well to stick to plagiarism, cuz you're in over your head trying to go solo.

Rick,

Regarding Varmint Al's info...

As to the barrel timing (during upward barrel movement), I agreed with you earlier. Its physics. The slower bullet and faster bullet can intersect but won't have the same POI at all ranges.

One problem with the pretty plot that Al shows is that there is no reference to the actual velocities between GOOD and BAD. You can compare the delta between the exit times but this doesn't tell the whole story in terms of bullet acceleration. I couldn't find any supporting documentation for that plot so I think its more of a pretty illustration to show the idea than actual data. For most other plots he provides a description. If you run some rough calcs assuming constant accel like Al does elsewhere you'll see that even a 100 fps difference in bullet velocity won't have the extreme GOOD and BAD that the plot shows. Exit times would still be very close. If you look around his site you can see his plots that show the same.

Also barrel harmonics and vibrations are very interesting and get mentioned a lot by ladderers it seems but, farther down on Varmint Al's page there is an experiment by Dr. Geoffrey Kolbe of Border Barrels.

This was the conclusion (I added bold typeface):

"CONCLUSION.... Maybe the "consensus" was that a rifle barrel vibrated in one or more of the mode shapes when fired. That was because the mode shapes and frequencies were easy to calculate and they did seem to answer some of the questions. From these FEA dynamic pressure calculations, it appears that the recoil and forced deformations are much more important than the natural vibration modes in determining where a barrel is pointing when the bullet exits the muzzle. Then after the bullet exits the muzzle, the rifle barrel vibrates in its various natural frequencies and mode shapes. Put another way, consider a guitar string being plucked. One pulls the string into a position (forced position) then releases it and the string vibrates at is natural frequency. The recoil and bullet motions "pulls" the rifle barrel to a new shape and once the bullet leaves the barrel, then the barrel vibrates. However, the addition of the scope to the model has shown some small high frequency vibrations superimposed on the forced deformations, both of which, slightly alter where the muzzle points before the bullet exits. For lowering the amplitude of the high frequency vibrations, it appears that even an "out of tune" tuner is better than no tuner at all."

Jordan,

Ok, curious what SD and ES numbers have you seen, ballpark, that coincide with good LR loads? I was going to say that even slightly higher SD would eventually come into play at longer ranges but your 1-mile shooting seems to show otherwise.

And to make sure I am understanding this...

Kiss to eliminate the inconsistent bullet jump (ring the bell "through" the bullet, instead of slamming the bullet into the bell?). I think the goal is to ring the bell (barrel) the same way each time the trigger is pulled.

And top pressures for decreased barrel time and consistent burn rate?

Jason

That is a piercing.

Lessoned learned => Pay attention to the details or your ladder will not work.

Can't take you all anywhere!

That bother you?
Is your puzzy hurt?
I feel bad now.

dave

I guess Berger doesn't know what they are talking about either.



And in case you still don't believe me:

Berger Bullets Line and Design

John

Gibby,

Last pass home,I got a pard's mind right on Iron's. Unlimbered a Winny 69 that's been setting static,installed a taller front sight and bottomed out the aperature rear,sdo as to eek a 50yd zero and then a guy could stretch the Old Gal out and do a leetle sumptin'.

It ain't Annie Iron's..but what is?!?(grin)











'neth,

I couldn't begin to speculate on your 58gr load,as I know nothing of it's chamber dimensions,the throat geometry,COAL latitude and where you are at in kisstitude.

Though I could ring the bell in about 3-pokes.

Hint.









rost',

Cain't wait to hear you mention how [bleep] incredibly clueless you are today...20yrs from now.

Laffin'!

Pay a leetle attention and it'd save you decades.

Wow +P+!









4th,

The key is to ring all the bells and contrary to Window Lickers' beliefs,it ain't not thang to ascertain just that and in veddy,veddy quick fashion.

As to ES/SD,it comes from good componetry and an inkling in their assembly. Bore condition/maintenance is hilarious schit and these stupid [bleep] couldn't sneak up on a glass of water.

Long story short,good ES/SD...will never hurt the equation and I just might look for that very thing. Hint.(grin) That from Rimfire to all thangs Centerfire,in regards to a rifle.

I've seen me be a .003" constriction Moly Slut,kissing the [bleep] outta things for many many moons and many many barrels. The "trick" is to let a new/pristine bore foul and that's a mebbe 12 poke affair at most...then one can start the hunt for pressure,knowing that has become a constant.

Assumin' a seasoned spout,it's just a coupla pokes and Show Time...because one will reliably know well in advance that ES/SD are in his hip pocket,due componet selection and their handling.

Funny how it actually works.(grin)

Not that I don't get a [bleep] kick outta a Smoke & Ladder Treatise by [bleep] Window Lickers doing their "best".

FUNNY schit!









'lia,

Show me the chart,where your "keen" eye and vast "experience",steered you to vote for Obama.

Twice.

You poor poor stupid [bleep].

Laffin'!










Pouty Hunter,

Cat got your tongue or the couch got your kchunt?!?

I know,I know...both.

Laffin'!

Boxer-

Very nice site. Fun to play with. Works when it gets serious.

Tack driv'n aperture for sure.

Heavy duty!

As Boxer said, low SD/ES numbers will never hurt, but I've seen good LR loads with little vertical that had an SD over 10 but under 15, and ES usually under 20. Keep in mind, these SD/ES numbers are usually coming from a statistically insignificant sample size, so unless they've come from a whole lot of shots over the chrono, I never put too much stock in them. Results on target matter more to me than SD/ES numbers gleaned from a couple of 5-shot groups, but if SD/ES happen to be sub-10, it doesn't hurt my feelings at all.

Yup, on the kiss. Start a straight bullet (concentricity matters when dealing with accurate rifles typically used for LR play) touching the rifling so as to keep things straight and aligned. Top pressures tend to cause powder to burn efficiently and consistently.

Both of those factors play nicely into keeping things constant and as invariable as possible from shot to shot...