I have yet to work with a barrel with a rifling twist rate quicker than 1:8 inches, but those who have tell me that while the occasional rifle will shoot 80-grain bullets quite accurately, most rifles prefer 90-grain bullets only and will seldom deliver acceptable accuracy with anything lighter. A twist rate of 1:8 inches is the best compromise for those who wish to shoot reasonably light and reasonably heavy bullets in the .223 Remington, and it is what I prefer for all-around use.

Some bullets weighing less than 50 grains will absolutely not work here simply because the centrifugal force tears their thin jackets apart in flight before they reach the target. This is of no consequence to me since I prefer 50- and 55-grain bullets when shooting varmints with this cartridge. On the opposite end of the bullet weight range, the 1:8 twist is just about perfect for the long 80-grain Sierra and Berger match bullets that many competitors have proven to be entirely adequate for shooting out to 600 yards--a few more are using them successfully at 1000 yards. That's as far away as I intend to shoot at anything with any rifle in .223 Remington. In other words, if it can't be done with the 80-grain bullet, I probably won't try doing it with one weighing 90 grains.

When choosing bullets to shoot from your AR15 don't overlook the fact that the extremely heavy-for-caliber bullets are intended for single-shot loading only and they were designed to be seated out to a greater overall length than the magazine box will handle. Maximum overall cartridge length for the magazine is around 2.275 inches, and with some of the heavyweights seated to that length, part of the case neck is out over the ogive of the bullet rather than over its shank with the result inadequate case neck tension on the bullet. On top of that, they would extend quite deeply into the case and use up a lot of what is already a fairly small powder space. As a rule, the Sierra 77-grain MatchKing and Berger 73-grain VLD are the longest bullets that should be seated deeply enough to feed from the magazine. All the others should be seated out of the case for single-shot loading.

Selecting Optimum Propellants
Some of the powders that have proven to be ideal for use in the .223 with bullets in the light to medium weight ranges are a bit quick in burn rate for the heavyweights. For example, Reloder 7 is an excellent choice for bullets weighing anywhere from 40 to 55 grains, but the slower burning Reloder 15 is a better choice for those weighing 60 grains and up. The same applies to other brands of propellants. For 40-grain bullets Sierra recommends powders such as VihtaVuori N-130, IMR-4198, and Hodgdon H322 whereas slower burning powders such as VV N-550, IMR-4064, and H4895 are recommended for the 90-grain MatchKing.

Using The Right Primers & Cases
Regardless of bullet weight, most of the powders suitable for use in the .223 are ignited quite uniformly by standard-force primers. I am partial to the Federal Gold Medal 205M; the Winchester WSR is quite popular among those who shoot the AR15 in Service Rifle competition.

ONE SUPER ACCURATE RIFLE

The test rifle I used when shooting various handloads for this report was a Super Varmint from Les Baer Custom, and it was not the first one I have worked with. Several years ago I shot the same rifle with a 1:12 twist, and it consistently delivered five-shot groups of less than an inch at 100 yards with both handloads and factory ammo. The rifle I shot more recently was basically the same except for the quicker 1:8-inch twist rate of its barrel. With LBC precision EDM scope mounting rings holding a brilliantly clear Weaver 6-20X Grand Slam scope atop its flattop receiver, it weighed two ounces beyond 12 pounds on my postal scale, and that along with its incredible accuracy potential made shooting tiny little groups falling-off-a-log easy. The group I am most proud of was fired with the Sierra 77-grain MatchKing seated atop 24.0 grains of Reloder 15. I wanted to shoot that load through the magazine so I used the Sierra-recommended cartridge overall length of 2.260 inches. Fired from a benchrest at 600 yards on a windless day, the group is a 10-shooter and it measures an incredible 2.842 inches (or roughly 0.474 minute-of-angle). Can I repeat that performance on demand? Probably not. Is the rifle capable of doing it all the time? Most definitely. One of the reasons I was able to shoot the Super Varmint so accurately is its trigger. Of two-stage design, it is from Jewell; the trigger finger first takes up the initial stage with 34 ounces of pull and then suddenly at the 42-ounce mark it breaks cleanly. AR triggers don't get any better than this. The barrel is benchrest-grade 416R stainless, and its size accounts for a good bit of the overall weight. The 24-inch barrel has a muzzle diameter of .925 inch. The Super Varmint is also available with 18- and 22-inch tubes, and rifling twist rate options are 1:7, 1:8, 1:9, and 1:12 inches. Upper and lower receivers are precision-machined from forgings, and the former is available with or without forward assist. These and all other parts, such as the chromed bolt and carrier, extractor, aluminum gas block with Picatinny top rail, and the free-floating tubular handguard, are manufactured in house by LBC. Accessories included in the package are quick-detach Versa Pod, 20-round magazine, padded rifle case (with side pockets big enough to hold lots of stuff). Like several other AR15 variants offered by LBC, the Super Varmint comes with a half-minute-of-angle guarantee. Believe me when I say it is no brag.

Any good brand of case will do for target practice and varmint shooting, but Winchester brass is probably the most popular among competitors due to its hardness and excellent weight uniformity. For trouble-free chambering in the AR15, cases should be full-length resized rather than neck sized. Top-quality, out-of-box components properly assembled on any good single-stage or progressive reloader will produce ammunition capable of half-minute-of-angle or better and that's good enough to satisfy most of us. I am sure it is also far better than the original designer of the M16/AR15 rifle ever dreamed of achieving with what went on to become America's longest-lived battle rifle.