Loading accurate .308 for an AR-10?

[SWThomas]

I've been loading pistol ammo for a while now and am ready to take the next step and reload some of the .308 brass I've been accumulating. The only .308 I own is a GA Precision GAP-10 with an 18" barrel. It shoots great groups with various factory ammo I've tried and I want to try to replicate that. My initial plans were to try to reverse engineer some of the best shooting bullets. What I mean is, take a myriad of measurements, pull bullets, and try to duplicate the round dimensions. Is that a legitimate way to approach creating my initial test rounds? Of course I would do a ladder test since I have no idea what powder the factory uses.

The most accurate rounds I've fired with it are: Black Hills 168g & 175g Match HPBT, Nosler Custom Competition 168g & 175g, and Copper Creek 175g SMK Gas Gun.

I know the set up is a little different for auto loaders than it is for bolt guns. Is there anything specific I will need to be aware of?

I've already got a box of 175g SMK HPBT bullets and a whole bunch of once fired brass. I still need to get primers and I'm going to start with some Ramshot TAC if I can find it. I also plan to hunt with this rifle some day. I'm a big Barnes fan and will probably work something up with their game bullets. Maybe some SGKs or some Noslers. I'll be getting Dillon dies for my 550 and all the other accessories I'll need.

Any help would be greatly appreciated.

[Bart B.]

While some claim cases for semiautos must be sized differently than bolt guns, I don't think so. My reasoning is the same lot of commercial match ammo shoots just as reliably and accurate in both. So, full length resize fired cases setting their shoulders back to virtual new case dimensions that's worked so well in bolt guns and shoot 'em your gas gun. With good ammo, there's virtually no accuracy difference between new and resized fired cases.

Using the same cases, medium weight bullets, powders and primers that shoots accurate in bolt guns, they will do the same in gas guns.

Why would there be a difference?

One exception, however. If the gas gun's bolt face is not squared up well with the chamber axis, fired case heads will also be out of square. They don't square up when resized. Accuracy with reloaded cases from such a rifle will not shoot as accurate in that same rifle as they did before.

I think Ramshot TAC is too fast a powder for 150 to 190 grain bullets in a .308 Win. case. Besides, it's a ball powder and such stuff has never shot as accurate as extruded powders. IMR4895, Varget, IMR4064 or N140 are better choices base on their success in competition.

[NWPilgrim]

Eventually you will need a case trimmer: lots of choices from $10 - $250.

I have not used TAC but Varget and BLC2 works well for me in .30-06 and 165-168 gr bullets. A slightly slower powder may give more velocity but these are accurate for me.

I find at least for me only a 1/8" - 1/4" difference in accuracy between Hornady AMAX, Sierra Matchking, and Nosler Custom Comp in 168 BTHP. I get whichever one happens to be available and cheapest at the time.

Surprisingly I found the Remington 165 gr Corelokt SP to be as accurate as one of the 168 gr BTHP; 3/4" 5 shot group at 100 yds.

I have not tested the Barnes TSX in .308" yet but I am very impressed with the 62 gr TSX in .224". Very consistent weight and dimensions and nearly as accurate as the Matchkings in .224". Fantastic bullet.

[Eppie]

Besides, it's a ball powder and such stuff has never shot as accurate as extruded powders.

I have seen this comment many times on this and other boards, and when I first started reloading, and I believed it. Unfortunately I wasted lots of time and money playing with extruded/stick powder that did not measure well on a progressive press. I've ultimately ended up using Winchester 760 and 748 (ball powder) because I went back and re-read the manual, and sure enough it says to use ball powder.

In conclusion, if you have a single stage press use whatever powder you like, in a progressive press use ball powder. Read your manual carefully. And remember if its on the internet it must be true, right?

[Jimro]

Try 41.5gr to 42.5 grains of IMR4064 in your Black Hills brass using CCI-BR2, Federal GMM, or Wolf Large Rifle primers under a 175 SMK.

Jimro

[hodaka]

I no longer own it but my DPMS 24" rifle was boringly accurate with either 41 gr. of 4064 with a 168 gr. SMK or 44 gr. under a 155 Palma. I full length sized the brass and used CCI 34 primers. I had many 5 shot groups of both that were under an inch at 200 yds.

[Eppie]

SWThomas, I went back and re-read your post and now realize that you are using a Dillon. Your choice of powder is good since it is a ball powder. Availability will be the issue. For bullets over 168 grains Winchester 760 is also an option, but it costs more than Ramshot TAC.

I also started out reloading for an AR-10 (POF-308), but later decided to focus more on accuracy and ended up getting a bolt gun. You will no doubt discover that accuracy is a very demanding mistress.

The major issues you will encounter, as you reload your brass multiple times, is stuck cases. As you re-use the brass the pressure causes the necks to get ticker and they get stuck. (I used Federal brass and it only took two firings for that to happen. I've found Glen Zediker book helpful in helping me to see things from a different perspective.) You will have to learn about "runout", or as many like to say "concentricity". More tools.

The bottom line is that loading for accuracy takes three things, money, time and inclination. Two out of three wont do.

[mdmtj]

My initial plans were to try to reverse engineer some of the best shooting bullets. What I mean is, take a myriad of measurements, pull bullets, and try to duplicate the round dimensions. Is that a legitimate way to approach creating my initial test rounds?

You aren't going to be using the same components as the factory so why concern yourself with factory measurements?

Determine what bullet you want to use, research load data for that bullet, and start loading based on the documented load data. Tailor the round for your rifle.

[Bart B.]

Eppie's remarks:

I have seen this comment many times on this and other boards, and when I first started reloading, and I believed it. Unfortunately I wasted lots of time and money playing with extruded/stick powder that did not measure well on a progressive press. I've ultimately ended up using Winchester 760 and 748 (ball powder) because I went back and re-read the manual, and sure enough it says to use ball powder.

Everybody knows ball powder meters more uniform charge weights than stick powder. But exact charge weight's are way down the list of what's needed for best accuracy. Even when exact charge weights of ball powder produce the most uniform muzzle velocity and peak pressure, metered stick powder with a 3/10ths grain spread typically produces best accuracy in cartridges popular in competition in spite of greater spreads in peak pressure and muzzle velocity. Go figure that out.

Benchresters meter stick powder to win group matches and set records. Sierra Bullets meters stick powder for ammo used to test their bullets for accuracy; they don't work up loads when changing barrels or component lots and I doubt anybody shoots their stuff as accurate as they do. Eppie, you might consider hanging out with folks who do this stuff and learn from them the realities and advantages of extruded stick powders over that round stuff. Or do your own thing; whatever.

Does Dillon's manuals say never to use stick powder or just that ball powder meters more uniformly? Many ammo loading facilities high speed machines have no problems metering stick powder in 22 caliber and larger cases. A pair of Dillon 1050 progressives made one of the most accurate .308 Win. ammo lots in history metering IMR4895 into .308 Win cases ending up with a 3/10ths grain spread yet the ammo shot no worse than 1/2 MOA at 600 yards in a couple dozen barrels from around the world. Federal Gold Medal Match .308 ammo's shot darned near that well in semiauto service rifles with IMR3031 and IMR4064 metered to the same spread. It's amazing to many that a good lot of it will shoot darned near 1/2 MOA at 600 in well built M1's and M14's or M1A's. And a bit better in good bolt action rifles.

I've never worked up any .308 Win load except once when a new bullet weight and shape came out. I just used the same components and amounts as others did in full length sized cases and they shot as good as the best of others. I've considered a waste of time to try something other than what's already been proved the best by dozens (hundreds?) of the winners and record setters.

[Eppie]

Bart, when I used Varget and IMR 4064 with my Lock n Load AP press I got a variance of +/- 0.4 grains. That's a .08 grain spread. I assume that most would agree that it does affect accuracy. If I'd gotten a 0.3 grain variance I would have been quite happy. But that's not my experience.

But when it all said and done why pick a powder that doesn't measure well?

I do hang around the 1,000 yard range and a lot of the guys do use extruded powder and it works well for them. They use single stage presses, but many guys that use progressive presses use ball powder too. If you're selling extruded powder I can understand taking offense to my statement, but I don't have an ax to grind here. I'm just stating my experience.

[Jleote]

I had great success with my AR based 308 (DPMS LR-308) using the old reliable IMR 4320. (with a 168gr bullet) Sub moa up to 300 yards with ease. (Maybe more but that's the longest range I can find locally)

And the only sizing issue I ever had was needing to reduce the OAL just a bit for magazine clearance.

[57K]

My shooting partner has a Savage M11 and it didn't take a lot of effort to build a sub MOA load using TAC and a 150 gr. Ballistic Tip with slightly over 2800 FPS velocity. Accurate 2520 is another good one as is W748. There are probably better powders than TAC for heavier bullet weights. If you really want to use a ball type powder with 168 and 175 gr. bullets in an AR, W748 is at least worth having on the bench.

[kln4]

When I first started reloading I started with my AR10B, Sudan ver. I bought the load manuals, read the internet, watch videos, and talked with people at the range. Everyone has a preference and they're all different, but I got some pretty good ideas.
I settled on Varget, cci lg rifle primers, and Hornady 168gn BTHP. And I've been using it for years. I also use the same load for my M1A. but I may change that this winter and try the n140 I got.

[Jimro]

For an AR10 I have no problem recommending a ball powder. There should be no problems getting sub MOA ammo with a ball powder. You might be able to shrink that group a fraction of an MOA with a stick powder, but at some point you either decide "good enough is good enough" or you don't.

If you can make sub MOA ammo, then a miss is on you, not the load.

Jimro

[Bart B.]

Eppie, I don't take offense at anything you've put in print on this forum. I just disagree.

Thanks for mentioning the progressive press you use. Now I understand why you want to use ball powder. I don't think Hornady's LNL progressives were designed nor intended to make super accurate ammo anyway.

It's my opinion that any powder measure setup that won't meter Varget no worse than 2/10ths grain or IMR4895 and IMR4064 into no worse than 3/10ths grain needs help. One thing a lot of folks have done with such measures is to solidly mount them so they don't wiggle inconsistantly when used; much more uniform charge weights.

I know several folks who've set records winning matches using comsumer progressives or huge commercial high speed progressives metering Varget, IMR4895 and IMR4064 into no worse than 3/10ths grain charge weight spreads. Some tried all sorts of ball powder that metered to 1/10th grain spread but none the ammo made with it shot all that great. Especially when Lake City army ammo plant used ball powder in its 1980's match ammo with poor accuracy at its best.

[Eppie]

I don't think Hornady's LNL progressives were designed nor intended to make super accurate ammo anyway.

Bart, I moving towards agreement with you on this. The LnL AP was my first press I bought and there are several things that I really like about it. But to get the results I want I may have to buy another press for rifle ammo. I like the progressive press concept and some of the guys use Dillon. But the idea of a single stage Forster Co-Ax is also percolating in the back of my head. Maybe later I'll start another thread.

I'll probably keep the Hornady and just load pistol ammo on it. What do you think?

[Jim Watson]

I agree with Bart.
In my limited experience of three barrels in two target rifles - all I have good enough for Long Range shooting - extruded is better. I tried hard to like Ball powder but the only one of the three that was as accurate with ball as extruded was Savage factory barrel. And that one replaced when they reduced the size of targets for F class because it was of only medium accuracy at its best.

My .22-250 WILL shoot as accurately with Ball as anything, but I still think the smart money is on extruded.

I am not a good enough loader and shooter to tell a difference between the several suitable extruded powders. I had just as soon load Varget, Re15, 4064 or 4895. But all did better than 2520, 748, or 760.

[Bart B.]

Eppie, now your cookin' good stuff in your brain.

Progressives are the cat's pajamas for reloading for handgun ammo. A 3/10th grain spread in 10 grain powder charges is only a 3% spread. That'll cause a few tenths inch vertical shot stringing at 50 yards for handgun bullets. So, if you and your stuff shoot good enough to see that, then use single stage presses for handgun ammo and weigh every charge.

[SWThomas]

Thanks for all the great info fellas!!! Looks like my money will be spent on extruded powders. I have no problem weighing the powder charges by hand and filling the cases in loading blocks. At least I'll do that for my precision stuff. For my plinking stuff and hunting loads I'll probably just use the press powder measure.