Rifles

The time around the turn of the 20th century was the heyday for machine-gun designers. Some designs were tested and a few adopted, but most never got off the drawing board. Still, it wasn't long at all before the world's armies recognized that a semiauto rifle would be a nice-to-have.

Immediately after WWI the U.S. Army began actively investigating the design of a semiauto rifle. By 1930 this work produced a shoot-off between two designs, one by John Garand and one by J.D. Pedersen. Both rifles used a new cartridge called Caliber .276. Accounts suggest that the competition was quite close, but the Garand was finally selected.

When the weapons-development folks approached Gen. MacArthur (then the Army Chief of Staff) with a request to build a quantity of operational test weapons, they were told that the .30-06 would remain the service caliber. The reason for this decision may have had as much to do with existing inventory as with anything else, but the decision stuck. The Garand's caliber was converted, and the rest is history.

The .276 cartridge, more popularly known as the .276 Pedersen, never achieved civilian production status either. It is a conventional bottlenecked cartridge a bit smaller than the '06. In fact it's very nearly identical to the dimensions of the 6.5x54 Mannlicher.

G&A editor Richard Venola located a supply of 1929 U.S. Army Caliber .276 ammo, and I volunteered to assist in a project to see how this 80-year-old design would compare with modern calibers. It turns out that the .276 Pedersen is an excellent medium-size cartridge, even by today's standards.

The old ammo had several ugly features that required more than a little work before we had reloadable cases. In the first place, the primers were corrosive so careful barrel cleaning was mandatory after we shot some for calibration. The primers had been staked in military style, and that necessitated a complete reaming and chamfering of the primer pockets before modern primers (Standard Large Rifle) could be inserted.

The old brass was too brittle to resize without splitting, so it was necessary to anneal the necks (see sidebar). Then came the problem of dies. Hornady's technical folks were interested enough in the project to furnish us a set. Besides conventional full-length resizing of Frankford brass, these dies will resize new 6.5x54 cases from Norma to .276 Pedersen in a single operation, saving all that messing around. It is necessary to trim about .070 off the necks to match the .276's case length.

Reloading itself is straightforward. The original military loading was about 331?2 grains of IMR 25 behind a 125-grain FMJ boattail bullet. You've never heard of IMR 25? Well, join the club. I couldn't find anyone who had heard of it either, even at the powder companies. It turns out that this is a powder that has a very similar grain size to IMR 4198. The burning rate is also pretty much a match with IMR 4198. The .276 case holds about 43 grains of water to the base of the bullet, so a 33-grain charge seems a bit off base. My experience is that the Army's technical folks aren't stupid, so I'm not going to poke fun at their choice of powder. The IMR 25 may have been the best they had available. It's so bulky that 331?2 grains pretty well filled the case. Still, with today's powder selection we can get better performance than they managed originally.

Instrumented firings showed that the original pressures closely matched the .30-06's numbers. That shouldn't be a big surprise. At the time the pressure level was selected for the .276, the .30-06 cartridge had been around for more than 20 years. The '06 had just gone through WWI, so pressures on the order of 55,000 cup and about 62,000 psi had recorded a lot of satisfactory history.

The .276 Pedersen has a bore diameter of .284 (7mm), and there are plenty of great 7mm bullets out there. And since we have a plentiful supply of suitable powders today, we can improve on the original military performance numbers.

The .276 Pedersen would be a good choice for single-shot pistols with about 15-inch barrels. Muzzle velocities will be about 160 fps slower than the numbers for 24-inch barrels. Slightly milder than the 7mm-08 but more potent than the 6.5x54, it's a completely adequate caliber for deer-size game.

WARNING The loads shown here are safe only in the guns for which they were developed. Neither the author nor InterMedia Outdoors Inc. assumes any liability for accidents or injury resulting from the use or misuse of this data.