Questions on precision AR 15 reloading

[searcher]

My thoughts on the various posts; Small base dies are usually NOT needed if shooting commercial brass. If the chamber in my rifle did not require a small base die to reliably load ammo, I would prefer to not use one. I want my brass to fill the chamber as much as possible and still function properly. If you plan on using previously fired military brass - I would recommend, as Biged51 did - to first size it with the short base die. My experience (40 years with a multitude of a/R's) has definitely caused me to formulate my own opinions, based on many tens of thousands of rounds loaded and fired. I would not expect a 16" carbine with open battle sights or a crappy, low-powered scope to give the accuracy desired for small varmint shooting. A lot of the guys who say their A/R shoot like s..., or say yours will too - probably have one of the shorter barreled models, one with bad optics or never treated the A/R with the same reloading protocol they would have reserved for their bolt guns.With A/R's having at least a medium-weight contour of 18" or more, a free-floating hand guard, an upper and lower that fit precisely and have a bushing to prevent movement when locked up, a decent barrel, smooth trigger and good optics - diligent hand-loading should produce 1/2 m.o.a. or better. Lots of books out there to read - but 95% of your accuracy will be the barrel, trigger, receiver lock-up, free float guard and your hand-loads.I have many of the "standard" and the thick, machined "heavy wall" receivers and I have seen no difference between them relative to obtaining 1/4 to 1/3 moa. I strive for 1/4 to 1/3 m.o.a. in all my varmint rifles and, while they will all do it, some took a LOT of load work-up to get there, changing powders mostly - and sometimes the intended bullet. I have found that once finding a good bullet/powder combination, primer selection made surprisingly little difference. Lots of folks say to not mess with the necks on A/R's, though I "safely" disagree. Turning necks for an A/R is not to bring the brass down to a tight neck chamber such as for your Dasher, for example - but to make them uniform - and nothing else. All batches of brass have a minimum average dimension and a maximum. The idea is to bring them down (or close to) that minimum - AND NO MORE. Taking off, for example, several thousandths more than that, and your necks may not retain enough neck tension to properly hold your bullet, even with a bushing die. I find that one of the biggest benefits in accuracy for my A/R's (on the loading end) came from neck turning, using a bushing die (I use Redding), sized .003" smaller than the bullet, sometimes .004", depending on the bullet surface area, brand, etc.. With necks of equal dimension, one can impart enough tension on the bullet with the bushing dies to provide "just enough" tension to prevent bullet movement and forego crimping - which is a contributor to fliers. Ammo manufacturers don't turn necks. Each crimped round therefor should have a different tension. Again, uniformity is lost. Uniform necks, make for uniform tension and uniform release. I don't crimp, though I always am sure to use enough neck tension to ensure that the bullet does not move when loaded. Not sure? load some uncharged rounds, let the bolt slam them home, then eject and remeasure using Hornady Lock n Load tool. Next, pay attention to the head space. This is super important. I set my shoulders back no more than .003". I believe this is the number one reason for crappy shooting A/R's. A "mil-spec" chamber is too large to promote accuracy. Making the brass fit the space better is KEY to good, if not consistent accuracy. That goes back to why I won't use a short base for normal reloading. One of the biggest, and most common mistakes made when setting up a die for head space is using previously fired military brass - even though it may have been cycled through the gun once or twice. It is VERY common for the shoulder to not fully move forward when fired in a mil-spec type of A/R chamber. This is akin to firing a case in a bolt gun where the shoulder was pushed back way too far and the bullet not jambed when fired. The shoulder simply never blows forward and you use end up using an erroneous measurement as the shoulder may be .008" back and you add another .003" to that. Kind of like making sloppy factory ammo and not knowing it. Good luck!

 

[Arbrn Ranger]

My thoughts on the various posts; Small base dies are usually NOT needed if shooting commercial brass. If the chamber in my rifle did not require a small base die to reliably load ammo, I would prefer to not use one. I want my brass to fill the chamber as much as possible and still function properly. If you plan on using previously fired military brass - I would recommend, as Biged51 did - to first size it with the short base die. My experience (40 years with a multitude of a/R's) has definitely caused me to formulate my own opinions, based on many tens of thousands of rounds loaded and fired. I would not expect a 16" carbine with open battle sights or a crappy, low-powered scope to give the accuracy desired for small varmint shooting. A lot of the guys who say their A/R shoot like s..., or say yours will too - probably have one of the shorter barreled models, one with bad optics or never treated the A/R with the same reloading protocol they would have reserved for their bolt guns.With A/R's having at least a medium-weight contour of 18" or more, a free-floating hand guard, an upper and lower that fit precisely and have a bushing to prevent movement when locked up, a decent barrel, smooth trigger and good optics - diligent hand-loading should produce 1/2 m.o.a. or better. Lots of books out there to read - but 95% of your accuracy will be the barrel, trigger, receiver lock-up, free float guard and your hand-loads.I have many of the "standard" and the thick, machined "heavy wall" receivers and I have seen no difference between them relative to obtaining 1/4 to 1/3 moa. I strive for 1/4 to 1/3 m.o.a. in all my varmint rifles and, while they will all do it, some took a LOT of load work-up to get there, changing powders mostly - and sometimes the intended bullet. I have found that once finding a good bullet/powder combination, primer selection made surprisingly little difference. Lots of folks say to not mess with the necks on A/R's, though I "safely" disagree. Turning necks for an A/R is not to bring the brass down to a tight neck chamber such as for your Dasher, for example - but to make them uniform - and nothing else. All batches of brass have a minimum average dimension and a maximum. The idea is to bring them down (or close to) that minimum - AND NO MORE. Taking off, for example, several thousandths more than that, and your necks may not retain enough neck tension to properly hold your bullet, even with a bushing die. I find that one of the biggest benefits in accuracy for my A/R's (on the loading end) came from neck turning, using a bushing die (I use Redding), sized .003" smaller than the bullet, sometimes .004", depending on the bullet surface area, brand, etc.. With necks of equal dimension, one can impart enough tension on the bullet with the bushing dies to provide "just enough" tension to prevent bullet movement and forego crimping - which is a contributor to fliers. Ammo manufacturers don't turn necks. Each crimped round therefor should have a different tension. Again, uniformity is lost. Uniform necks, make for uniform tension and uniform release. I don't crimp, though I always am sure to use enough neck tension to ensure that the bullet does not move when loaded. Not sure? load some uncharged rounds, let the bolt slam them home, then eject and remeasure using Hornady Lock n Load tool. Next, pay attention to the head space. This is super important. I set my shoulders back no more than .003". I believe this is the number one reason for crappy shooting A/R's. A "mil-spec" chamber is too large to promote accuracy. Making the brass fit the space better is KEY to good, if not consistent accuracy. That goes back to why I won't use a short base for normal reloading. One of the biggest, and most common mistakes made when setting up a die for head space is using previously fired military brass - even though it may have been cycled through the gun once or twice. It is VERY common for the shoulder to not fully move forward when fired in a mil-spec type of A/R chamber. This is akin to firing a case in a bolt gun where the shoulder was pushed back way too far and the bullet not jambed when fired. The shoulder simply never blows forward and you use end up using an erroneous measurement as the shoulder may be .008" back and you add another .003" to that. Kind of like making sloppy factory ammo and not knowing it. Good luck!

What is the difference between "small base dies" and "large base dies"?

Why would I desire to use one over the other?

 

[Jet]

Read through the article at the link below. Should answer your question.

http://bulletin.accurateshooter.com...th-dies-neck-sizing-dies-and-small-base-dies/

Good Shooting

Rich

 

[Depart123]

Two things I didn't see mentioned:

1) Magazines have an effect on accuracy. Bullets single loaded either from the ejection port or single loaded from the magazine will produce substantially smaller groups in most rifles. The upward pressure from the mag drags on the bolt and causes inconsistent bolt lock up as the mag empties. So running the smallest mag possible, or just loading fewer rounds can help accuracy.

2) Most AR barrels these days are over gassed because manufacturers got tired of people buying match barrels, then feeding them crappy ammo before calling to complain that something was wrong with the barrel. So as a consequence, adjustable gas blocks have become almost a necessity if you want to shoot small with an AR.

 

[Depart123]

My thoughts on the various posts; Small base dies are usually NOT needed if shooting commercial brass. If the chamber in my rifle did not require a small base die to reliably load ammo, I would prefer to not use one. I want my brass to fill the chamber as much as possible and still function properly. If you plan on using previously fired military brass - I would recommend, as Biged51 did - to first size it with the short base die. My experience (40 years with a multitude of a/R's) has definitely caused me to formulate my own opinions, based on many tens of thousands of rounds loaded and fired. I would not expect a 16" carbine with open battle sights or a crappy, low-powered scope to give the accuracy desired for small varmint shooting. A lot of the guys who say their A/R shoot like s..., or say yours will too - probably have one of the shorter barreled models, one with bad optics or never treated the A/R with the same reloading protocol they would have reserved for their bolt guns.With A/R's having at least a medium-weight contour of 18" or more, a free-floating hand guard, an upper and lower that fit precisely and have a bushing to prevent movement when locked up, a decent barrel, smooth trigger and good optics - diligent hand-loading should produce 1/2 m.o.a. or better. Lots of books out there to read - but 95% of your accuracy will be the barrel, trigger, receiver lock-up, free float guard and your hand-loads.I have many of the "standard" and the thick, machined "heavy wall" receivers and I have seen no difference between them relative to obtaining 1/4 to 1/3 moa. I strive for 1/4 to 1/3 m.o.a. in all my varmint rifles and, while they will all do it, some took a LOT of load work-up to get there, changing powders mostly - and sometimes the intended bullet. I have found that once finding a good bullet/powder combination, primer selection made surprisingly little difference. Lots of folks say to not mess with the necks on A/R's, though I "safely" disagree. Turning necks for an A/R is not to bring the brass down to a tight neck chamber such as for your Dasher, for example - but to make them uniform - and nothing else. All batches of brass have a minimum average dimension and a maximum. The idea is to bring them down (or close to) that minimum - AND NO MORE. Taking off, for example, several thousandths more than that, and your necks may not retain enough neck tension to properly hold your bullet, even with a bushing die. I find that one of the biggest benefits in accuracy for my A/R's (on the loading end) came from neck turning, using a bushing die (I use Redding), sized .003" smaller than the bullet, sometimes .004", depending on the bullet surface area, brand, etc.. With necks of equal dimension, one can impart enough tension on the bullet with the bushing dies to provide "just enough" tension to prevent bullet movement and forego crimping - which is a contributor to fliers. Ammo manufacturers don't turn necks. Each crimped round therefor should have a different tension. Again, uniformity is lost. Uniform necks, make for uniform tension and uniform release. I don't crimp, though I always am sure to use enough neck tension to ensure that the bullet does not move when loaded. Not sure? load some uncharged rounds, let the bolt slam them home, then eject and remeasure using Hornady Lock n Load tool. Next, pay attention to the head space. This is super important. I set my shoulders back no more than .003". I believe this is the number one reason for crappy shooting A/R's. A "mil-spec" chamber is too large to promote accuracy. Making the brass fit the space better is KEY to good, if not consistent accuracy. That goes back to why I won't use a short base for normal reloading. One of the biggest, and most common mistakes made when setting up a die for head space is using previously fired military brass - even though it may have been cycled through the gun once or twice. It is VERY common for the shoulder to not fully move forward when fired in a mil-spec type of A/R chamber. This is akin to firing a case in a bolt gun where the shoulder was pushed back way too far and the bullet not jambed when fired. The shoulder simply never blows forward and you use end up using an erroneous measurement as the shoulder may be .008" back and you add another .003" to that. Kind of like making sloppy factory ammo and not knowing it. Good luck!

Great info....but paragraphs brother.....paragraphs.

 

[711rollerdog]

What is the difference between "small base dies" and "large base dies"?
With a small base die you can run your headspace out way further.. I bump mine back .002". Keeping the action/chamber clean is key.

 

[Shynloco]

I can see I got this party really late as others have pretty much covered all the bases. I have a custom AR15 built by my Gunsmith to copy his that he shoots in 600 yd competition. It has the matching billets made by San Tan Tactical out of Arizona. The remainder of the parts are all JP Precision (22" 1:8 barrel included ), the stock a Magpul w/adjustable cheek rest and the trigger is a 2 stage Geiselle. I shoot strictly 100 yds anymore mostly because of my eyes. And I shoot mostly 55, 69 and 77gr bullets with the best powder I've found to be VVN140 in this rifle. I agree that these type of rifle should not be compared to shooting a Benchrest Rifle. But who cares? I get sub moa 5 shot groups which is plenty good in my book. I use regular .223 Redding Dies and FL resize after each shooting and bump shoulders .002 using LC Brass. And forget the neck tension thing as AR's could care less. Whatever your die sets the neck to will work fine. Some ideas and principles in Benchrest reloading don't apply as a Gas Gun could care less. But do some testing as a 52 - 53 gr bullet shoots fantastic groups in my Savage VLPDBM bolt gun, but can't compete with the 55, 69 and 77's in my Gas gun.

Good luck and have fun. But like other have said, don't expect unrealistic results from any Gas Gun. Don't mean we can't try.

Alex

 

[Richard Coody]

i went through a stage of building AR's.

My favorite components for a precision AR were a matched billet upper/lower from CMT Tactical, Shilen 20" Hbar, Geissele SSA-E trigger. After much work and several trys i built one that i could consistently shoot 5 five shot groups on one target and the average of all the groups would be 3/4". those who say they have an AR that will shoot 1/2" hundred yard groups all day long need to take the 5 five shot group test.

There are some tricks to assembling a precision AR. Robert Whitley has some good stuff out there on assembling an accurate AR.

i have owned one AR that was capable of 1/4" hundred yard groups. that one was built by Robert Whitley. 6mm AR turbo 40 with a 26" krieger barrel and a Geissele national match trigger.

i have since passed out of my AR stage. those hbar rifles are just too heavy to be practical, AR's are hard on your precious brass and they really are hard to get accuracy out of.

That said i still have two. my truck gun. a stock PSA. and my hog gun a 6.5 grendel with a 18" lightweight JP barrel, Geissele SSA-E, silent capture spring, built on mur upper with a CMT billet lower. 1 moa gun with factory ammo. don't even bother to reload for either of my AR's

a set of forster benchrest dies is all you need. i have had quite a few AR's. Never felt the need for small base dies. Full length resize with a .002 to .003 shoulder bump works fine.

 

[searcher]

i don't think anyone here was trying to say A/Rs can compete on an accuracy level with a bolt gun. That said, on a windy day, better shooters than I whom are behind a more accurate bolt gun might feel the sting of what semi-auto brings to "beating the wind" - but that, of course, is the reason they are not allowed in most bench rest venues. Now - if they were so darn inaccurate, why would they not be allowed? And why would A/R's be insensitive to neck tension when bolt guns are not? Gimme a break.

 

[hpshooter]

", why would they not be allowed? " My guess, based on shooting service rifles in high power, would be the distraction of ejected brass landing on adjacent benches. The perceived advantage of using the semi auto to "beat the wind" would be canceled out by a requirement to single load as is done in the slow fire stages of high power.