Squeezing accuracy out of an AR

[Bookwalter]

Looking for a good staring point for getting every milimeter of accuracy out of my AR. It's a 16" bull barrel with a 1/10 twist.
I've had success with Nosler's ballistic tip bullets in the past with other calibers and will likely shoot them.
With the given twist rate, a 55 or 60 gr bullet should perform well. I'm interested in recommendations you can make for powders to try with this setup. Hoping to limit the experimenting by learning from the experience of folks out there.

Thanks for any input.

[DIXIEDOG]

If using a progressive I use H335 or TAC because it meters well and gives good accuracy. If I'm loading single stage and using my powder dispenser I use Varget because it is slightly more accurate in my guns, the stuff meters like crap so it isn't great for a progressive press in my opinion but the Chargemaster trickles every charge so it doesn't matter what powder I use in it.

[Ninth and Plum]

I also use H335 in my ar 15. I have had excellent results with 22grains of powder, cci 400 primers, and oal of 2.25. I know they call for the magnum primers but I have not noticed any difference in using standard primers. Also at 2.25 oal they are just about touching in the magazine end.

[Unclenick]

With a short barrel you want to lean to the faster burning rate side of powders to avoid too much unburned stuff being tossed out against the bullet base and also just to avoid wasting powder (nothing's cheap these days). I would also lean toward flat base rather than boat tail bullets because of the higher muzzle pressure that remains at the bullet's exit from a short barrel. That jetting gas adds to bullet axial disturbance. Look to a bullet like the Sierra 53 grain MatchKing with its flat base. The boat tail base is more susceptible to the jetting of muzzle gas because it is still leaving the muzzle when the jet starts. That exaggerates the deleterious effect of any slight asymmetry of the muzzle or bullet base on accuracy.

Look at using weighed charges of a powder known to produce accurate loads in the medium .22's, with the weakest good quality primer you can get. Stoner designed the AR for IMR 4198. I would start there. Reloader 10X is a bit slower, but was developed as a light bullet powder and does very well in the .223.

The Federal Gold Medal 205M primer is very good. It's reputation is that it is too sensitive for good resistance to slamfires in a gun with a floating firing pin, but I have never had one using them. If you prep your brass, including uniforming the depth of your primer pockets, you will be able to seat the primers deeply enough to reduce any risk of slamfires. The Forster priming tool, though not well-liked by some from the standpoint of smooth setup and operation, is, nonetheless, the only tool made with a ram design that ensures primers are fixed 0.004" below flush with the case head. That discourages slamfires. The same seater ram design is on the Forster Co-ax press, which is probably the best press for loading peak accuracy loads without getting into benchrest arbor press dies. More non-benchrest match winners who roll their own use it than any other press. The design allows dies to self-center with cases as they go in, and that makes for very symmetrical ammunition.

Try one of the sliding sleeve bullet seaters. I use the Redding Competition Seater Die. The Forster is a little less expensive but also has a good reputation; I've just got onto the Redding first and found it worked so well that I never had reason to switch. I did some seating experiments years ago and found the Redding reduced bullet runout in the .30-06 to almost nil. The only exceptions were cases with uneven neck walls. These still had runout, but only equal to the unevenness of their necks. If you sort your match cases with a case gauge, you will cull those uneven necks and see almost no runout with that seater.

You can use my spreadsheet of Don Miller's simplified twist rate estimation system. It will let you know whether a specific bullet will stabilize well in your barrel or not? You will need Excel or the free Open Office Suite spreadsheet program, Calc, to run it. You can get the file from my shooting file repository at http://www.drop.io/unclenick/. You will find the short bullets exceed the optimum stability factor in your barrel, but I don't usually have trouble with match bullets due to that.

I don't suppose I need to mention that you will want to shoot by loading singly for best accuracy. That is to avoid the bullet becoming tilted due to forces on it while it goes up the loading ramp.