July 17, 2025

The 45-70 -- Subsonic loads

ACME bullet put out this video with loads using 4 powders that gave velocities of 1050 fps --- They used their 405 grain coated bullet: 
Titegroup 10.5 grains - 1000 fps
AA-5744 20.5 grains - 1050 fps
IMR 4198 24.8 grains - 1050 fps
IMR 3031 30.5 grains - 1070 fps
Unfortunately, AA-5744 is (at this time) entirely unavailable.

Also note that he used IMR 4198, not H4198 (and these powders are not identical).

Beyond subsonic

The following video explored loads for their 405 grain bullet with velocities up to 1450 fps. They used 3 powders: IMR-4198, AA-5744, and AA-2015. I am entirely unfamiliar with AA-2015 and I know AA-5744 is impossible to get.
Here are the loads for IMR-4198: 
IMR-4198  31.0 grains  1250 fps
IMR-4198  32.1 grains  1300 fps
IMR-4198  32.6 grains  1350 fps
IMR-4198  33.4 grains  1400 fps
IMR-4198  35.0 grains  1450 fps
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Tom's Computer Info / tom@mmto.org