Very interesting post. WWI really was a collision of outdated tactics and modern weapons. “Over the Front” magazine published the reminiscences of a French captive balloon pilot who was armed with a Winchester SLR (caliber not stated) along with a photograph of him aiming the rifle and his drawing of the interior of a basket with the muzzle and cocking rod of his Winchester in view. He actually emptied his rifle at an attacking airplane and then bailed out after his balloon was hit. The ground crew was able to get the balloon back to earth but it burned on the ground.
I noted an error in the article; the weight of the .401 SL bullet is given as 7.65 grams (118 grains). In the U.S., this cartridge was only loaded with 200- and 250-grain bullets. Using the drawing in the article, I made some very rough calculations based on an average specific gravity of 10.9 gm/cm³ (Greenhill’s Formula, Hatcher’s Notebook) for a jacketed bullet and by reducing the round-nosed profile to a simple cylinder with a diameter of 10.35mm. A 7.65-gram bullet would be approximately 8.3mm (0.326") long, much shorter than the 18.6mm (0.732") long bullet illustrated. The reproduction is a little fuzzy, so I may be off to the right of decimal. A flat-based 16.2-gram (250-grain) bullet would be about 17.7mm (0.697") in length. A rough calculation for the reduction in weight caused by the base cavity gave about 0.5 grams (8 grains), resulting in a 15.7-gram (242-grain) bullet. Oddly, doubling 7.65 gives 15.3 grams or 236 grains, which goes along with “intended to lighten the projectile” in comparison with the 250-grain bullet.
Can anyone shed any light on this one?
By the way, what does “ART” in the headstamp stand for?