Left to right: .257 Roberts (introduced in 1934), .276 Pedersen, .30-06 Springfield. Note that the Pedersen has more body taper to support its intended use in semiautomatic 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.

.276 PEDERSEN LOAD DATA*
Bullet	Bullet Weight (gr.)	Powder	Primer	Case	Starting Load (grs.)	Maximum Load (grs.)	Max. Muzzle Velocity (fps)
Sierra HP	100	VihtaVuori N530	Win. Large Rifle	FA 29	32.0	38.0	3,110
Sierra HP	100	VihtaVuori N530	Win.Large Rifle	Norma	32.0	37.0	3,100
Barnes X	120	Norma N201	Win.Large Rifle	FA 1929	28.0	35.0	2,750
Barnes X	120	Norma N201	Win. Large Rifle	Norma	26.0	32.0	2,680
Hornady V-Max	120	Hodgdon Benchmark	Rem. 9.5	FA 1929	27.0	35.0	2,800
Hornady V-Max	120	Hodgdon Benchmark	Rem. 9.5	Norma	27.0	34.0	2,770
Nosler Ballistic Tip	120	FamShot TAC	Federal 210	FA 1929	28.0	37.0	2,800
Nosler Ballistic Tip	120	RamShot TAC	Federal 210	Norma	28.0	35.0	2,780
FA-FMJ 1929	125	IMR 3031	Rem. 9.5	FA 1929	28.0	34.0	2,600
FA-FMJ 1929	125	IMR 3031	Rem. 9.5	Norma	28.0	33.0	2,580
Barnes XBT	130	VihtaVouri N530	Federal 210	FA 1929	26.0	32.5	2,600
Barnes XBT	130	VihtaVuori N530	Federal N530	Norma	26.0	31.0	2,600
Hornady SST InterBond	139	Accurate 2230	CCI-200	FA 1929	29.0	36.0	2,650
Hornady SST InterBond	139	Accurate 2230	CCI-200	Norma	29.0	34.0	2,610
Nosler AccuBond	140	Winchester 748	Federal 210	FA 1929	29.0	37.0	2,625
Nosler AccuBond	140	Winchester 748	Federal 210	Norma	29.0	36.0	2,615

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.

The left-hand target was shot with original Frankford Arsenal 125-grain FMJ bullets (the standard Army .276 loading). Accuracy isn't terrible even by today's standards. The right-hand target was shot with Hornady 140-grain InterBond bullets. Eighty years has made a huge difference in bullet quality. Both targets were fired from the same barrel at 100 yards.

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.

EASY ANNEALING

As brass is worked, it gets harder and more brittle. A process called annealing can eliminate this. Annealing consists of raising the temperature of the brass to approximately 600 degrees and then quenching it. This leaves it more ductile and helps prevent splitting. The time-honored way to anneal cases was to stand them in a pan of water that covered about half the length of the case. Then the pan had to be rotated as the neck area of the case was heated with a propane torch. The water kept the heat from softening the base of the case (a bad thing). When the case neck got hot enough, the case was tipped over into the water to quench it. This method takes practice to learn and is slow and awkward. Hornady's Anneal Kit makes the process a lot simpler. The kit contains three aluminum cups that can be mounted in a drill chuck. The three cups have different-size cavities to allow them to be used with a variety of case sizes. The kit also contains a bottle of Tempilac. You paint a band of the Tempilac around the case where you want the annealing to end. The process then consists of spinning the case with the drill motor while heating the neck with a propane torch. When the Tempilac melts, the temperature is just right and you then tip the drill motor to dump the case into a pan of water. The aluminum cup protects the base of the case from the torch's heat. I used both methods to anneal case necks for the .276 Pedersen project, and I can assure you that the Hornady method is quicker and easier.

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.