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Post subject: Re: Which rifle powder is closest to the powder used in WW1 for30-06?
A little further info, mostly in regards to .30-06 match ammo. Pyro DG powder was used thru 1919. In 1920, IMR 17 1/2 was used. In 1921, IMR 1076. From 1922 to 1924, HiVel 2 powder. From 1925 to 1927, IMR 1147. In 1928, IMR 1185 was used. In 1929 and 1930, IMR 1186 was used. In 1931 they switched back to IMR 1185, and stayed with it thru 1940 when it was replaced with IMR 4895. The pre-war Palma and International ammo sometimes used a different powder than regular match ammo. Alot of precision load development was taking place in the 20's and 30's. The first year that a 172gr 9 degree BT bullet was used in match ammo (later designated M72) was 1925. -- Don
From US Army Ordnance School text, January, 1942:
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Cal. .30propellants. - IMR 1185 (Improved Military Rifle). - This powder is no longer standard for loading cal. .30 ammunition. It is found in the cartridges, ball, M1; A.P., M1; and in early lots of tracer M1. It is a nitrocellulose powder containing powdered tin or tin salts and coated with graphite which gives it a black, shiny appearance. The powder is cylindrical in form and has a single perforation through its long axis.
From what I could gather (which included no reloading data), 1185 sounds like it was not hugely agreeable with the M1 Garand. Sounds like it was one of the early IMR powders that the Ordnance Corps switched to in the mid-20s through the 30s, but then dumped in 1940 when 4895 came along. I know I've read somewhere about the reason the military disliked the early IMRs (although they were apparently better than the prior "smokeless" powders, such as Pyro D.G.), but I can't remember where right now.