Both IMR4895 and WC852 were original powders for the M2 .30-06 load. If you look at the military ammo spec sheets, nominally they gave the same velocities and pressures with the same charge weight. But there was a lot of variability from lot to lot in Ball powders and some of the WC852 ended up burning a lot more slowly than specified. We're seeing some of that on the market now. But some of it's still the "fast" kind, so be careful with the data. BTW, the original H380 was surplus WC852, but that doesn't mean you can necessarily use H380 data with the WC852 you can get now.
Same with the IMR4895. It isn't the same as the 4895 you buy at the gun shop today. The batch I have (which is "pulldown" from disassembled M2 .30 cal cartridges) is notably slower than the currently made stuff, requiring stepping up the load a good bit to get the same velocity. That's not always going to be the case, depending on the batch.
Surplus powders are great. I use them a lot, almost exclusively. But you have to regard each one as an unknown and work up your own loads using the suggested comparison powders to get a starting point only.
Posts: 424 | Location: Bristol, Tennessee, USA | Registered: 28 September 2003