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Old April 22, 2020, 06:48 PM   #51
Bart B.
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Now some smart ass will pipe up and say that the bullet has left the barrel before the gun recoils so that can't affect accuracy. Well, they would be right for the first part, but totally wrong for the last part.
He would be totally wrong about the first part, too.

All rifles move in recoil and the barrel vibrates before the bullet leaves the barrel. How its held has to be 100% repeatable from shot to shot. Muzzle doesn't point above the point of aim on target equal to bullet drop plus sight height until the bullet leaves the barrel.

https://www.varmintal.com/alite.htm is a good explanation.

Best proof is the fact that 4 people shooting the same rifle and ammo in a team match will have different sight zeros. And tuning weights near the muzzle adjust the muzzle axis vibration frequency so bullets leave on the upswing at the right place to compensate for their velocities spread.

Last edited by Bart B.; April 22, 2020 at 10:16 PM.
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Old April 23, 2020, 09:35 AM   #52
bfoosh006
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MarkCO

FWIW... Speculation wasn't the perfect word, so no intentions on implying anything negative at all.
I just don't expect a perfect 100% answer, for questions like I posed.
Somehow, someone ...does just like you mentioned... taking responses and picking them apart.


I fully agree, consistent parts interaction in a semi auto matters.. far more then most tend to agree with. ( Even down to the gas tube interaction )
There is always the group that say "The AR15 is a combat design so don't fuss about the loose fitting parts details"
And that is A-Ok with me if that is what they want.

I have seen accuracy ( precision ) improvements that are easy to do, so for me why not.

Again to each their own.

As for your answers... I guess I just hadn't gone down the rabbit hole quite far enough... Lol.

I am going to number my magazines, and try keeping that info.
I have seen many well respected M1A shooters say in matters.

But , to be honest, I didn't think that thorough far enough... and now see , as you mentioned, why it can matter.

Same thing applies to AR actions, firm believer in consistent easy part interaction.

FWIW... and just flying from the seat of my pants... Adj. GB's on typical gas ported Large Frame AR's sure seem to make it easier to shoot more consistently.

Simple logic would suggest a less "violent" cycling makes keeping your rifle on target easier... and allows the various parts to cycle more consistently.

And smoothing up an AR action sure seems to help me shoot tighter groups.... even down to the buffer tube smoothness.


Any way... I am rambling.. my point is, for anyone looking to improve the precision of their AR's.. IMHO, it can be done easier then some will imply.

Not everyone thinks those "tuning tricks" matter... but they sure seem to work for my AR's.


MarkCO... thank you for your useful , makes sense answers !

For those wondering.. I adhere to most of these tuning suggestions.

http://bulletin.accurateshooter.com/...latform-rifle/

Doing a lot of those tuning tricks ( lack of better words at the moment ) have produced some very satisfying AR groups.

Can I do these groups all day , every day ? .. Maybe not... but at least I know the rifle is capable of it.

Both groups , 10rds , 100yds... benched, scoped, bagged front and rear.. tuned by me. ( In other words...IMHO, If I can do it, so can anyone...the attention to details matter )

First, 10rds 155gr Horn. AG , 308 FN CHF CL 20" , Adj Gb, etc...

Second, 10rds Horn. AG 140gr 6.5CM, also with a Adj. Gb, etc...
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File Type: jpg bcs1wiqa-606179.jpg (118.6 KB, 10 views)

Last edited by bfoosh006; April 23, 2020 at 09:43 AM.
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Old April 23, 2020, 10:12 AM   #53
Bart B.
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I've been called every bad name in the English dictionary for assessing accuracy by the largest test group fired. Don't care about smallest groups, only what can be counted on all the time for the life of the barrel.

Most rifles will shoot at least one few-shot cloverleaf across a few thousand such groups fired.

How many cloverleafs are the result of invisible compensation moving bullet impact closer to point of aim than it would otherwise go? I once shot 5 bullets from a 308 Winchester into about an inch at 1000 yards using aperture sights. All were called inside a seven inch diameter area centered on the bullseye.

Last edited by Bart B.; April 23, 2020 at 11:42 AM.
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Old April 23, 2020, 10:24 AM   #54
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The only beef I have about the "how to make your AR great" link is that it mostly ignores the role of the cartridge itself--which , in the end, is going to affect how all the other components work.
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Old April 23, 2020, 12:06 PM   #55
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MarkCO

Fully agree... I take the link as a helpful article, not a solution to every aspect of shooting consistently small groups with an AR.

some more rambling...

Ammo plays a huge roll in the rifles ability shoot well. And Ammo that has fired awesome groups in on rifle barrel may or may not do the same in another barrel.

I have Port. 308 surplus that my M21 loves ( as much as it can for FMJ surplus ) .. but that same ammo shots like poop in my 20" FN CHF CL AR.

So ammo is certainly another very important part of the equation.

Another One of the best examples of ammo ( IMHO ) playing a big roll in accuracy, was the Federal 50gr Tipped Varmint .223 ... low priced, loaded in LC brass frequently ( with crimped primers ) bullet ogive and OAL that isn't even close to the AR barrels lands, loaded on mass production machines... IMHO, danged near XM loading , just with the Tipped Varmint 50gr bullet instead of a 55gr FMJ.... anyway, that stuff is crazy accurate from every AR I own, and numerous others AR's... yet fly's in the face of conv. accuracy reloading wisdom. So, IMHO that specific ammo recipe just worked... not available anymore.
And all that at $5.29 per 20rds at its cheapest. Best 100yd shooting skills, productive practice .223 round I have used. Every production Lot # was the same for me... cheap and consistently accurate.

And for Bart B., sorry to hear so many people freaking out about different accuracy standards.
The internet seems to be full of judgemental folks, always wanting to point out what "you ( or I ) " should have done.. rarely doing any test and results themselves.

I freely admit the 2 groups I pictured, are some of the best groups. Did those barrels shot everything as well... Nope.

But after finding factory ammo they did like "best" , I bought sufficient to enjoy the accuracy of it.

I also use those specific ammo's to instill confidence in "newer" shooters.

As for the largest groups fired... ZQI 308 and Port. BALL was like a shotgun blast at 100yds.... seriously bad. ( I didn't expect MOA from it... but dang, it was crazy bad. I'll see if I still have that photo )



The ammo those same barrels did like are consistently able to shoot well.. provided I do my part.

And stuff like the linked tuning tricks did show precision improvements in my non-scientific, I am going to try that testing. Using all the available ( at the time ) 6.5CM ammo I could find.

The rifle is a PSA 20" I have... again not a scientific analysis.. much more a seat of the pants.
But the tuning tricks improvements are significant enough to make me believe in the potential YMMV aspect to give them a try.
So for others reading this, I do suggest the tuning.

Every thing I did shouldn't produce any worse precision. Pay attention to the task at hand... again, if I can do it anyone can.

And I don't expect the linked article to be the perfect cure... ( heck anyone could be a millionaire if they could figure that whole big equation out )

But I do consider the "tuning tricks" to help put the "odds" in your favor.
After all, many of the tricks are proven and accepted in the bolt action world.

Much like buying a better quality barrel. Odds are, you will see improvements.

Pics... ZQI and surplus Port at 100yds from the same FN CHF CL 20"

And surplus that my Large Frame AR's love...

Sanitized DAG , 20rds rapidish fired from the bench, scoped, bags front and rear...
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Old April 23, 2020, 12:15 PM   #56
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I once shot 5 bullets from a 308 Winchester into about an inch at 1000 yards using aperture sights.
You are God!
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Old April 23, 2020, 12:37 PM   #57
Bart B.
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The 3.5 inch mean radius accuracy specs at 600 yards for military 30/7.62 caliber match ammo has been the standard for decades. 270 shot test groups at 600 yards with the most accurate lots were about 10 inches ES as fired from a Rem 700 match grade barreled action laying in a Mann rest. Other groups that passed were sometimes over 15 inches ES. Such is life when arsenal 173-grain FMJBT bullets come from 3 or 4 different sets of dies making them. 'Twas hard to keep 20 shots from M1 and M14 match rifles inside the 20 inch 5 ring, 12 inch V ring. Worse from 1966 and later when the target was changed to a 12 inch 10 ring, 6 inch X ring.

Rebulleting either 30-06 and 7.62 versions with Sierra 168 or 180 HPMK's ended up shootingn1/4 to 1/3 the size.
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Old April 23, 2020, 12:39 PM   #58
Bart B.
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Originally Posted by stagpanther View Post
You are God!
The devil made me do that. All those shots were in the 20" 10 ring at 4 o'clock, not in the 10 inch X ring where I called them. All 15 shots in that stage were scattered inside about 19" extreme spread.

Last edited by Bart B.; April 23, 2020 at 12:51 PM.
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Old April 25, 2020, 04:18 PM   #59
baddarryl
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Originally Posted by LeverGunFan View Post
In part an accurate firearm goes into battery the same for every shot. The alignment of the bolt and the cartridge to the chamber, and the alignment of the bullet to the chamber and the barrel are important. In a bolt action you can form the cartridge case to fit the chamber and single load the cartridges to avoid changing the position of the bullet in the case. In an auto loader you may need cases smaller than the chamber for reliable feeding, and the bullet may get slightly knocked out of position by the feed ramp. The bolt action has the potential to position the bullet more accurately with respect to the bore for each shot than does an autoloader. That consistency contributes to accuracy.
This ^^^
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Old April 29, 2020, 01:07 PM   #60
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Now some smart ass will pipe up and say that the bullet has left the barrel before the gun recoils so that can't affect accuracy. Well, they would be right for the first part, but totally wrong for the last part
Newton's laws of motion

Third law
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.


bullet movement and recoil occur simultaneously
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