I have successfully made 43 Mauser (43M) from 45/90 and 45/70, and it is not a complicated process.
- cut 1/2 of 17/32" K&S thin-wall brass tubing
- solder to the base of the 45/90, and anneal the case while you're at it. The casehead is annealed, but pressures will be low ~ Springfield Trapdoor
- turn the rim to 0.590" and the base to 0.520" (my chamber is 0.525", but this is all my dies will accommodate), trim to 2.375"
- F/L size
- load with a cast bullet sized to 0.448" (my bore is 0.446").
L to R - Dominion 43 M (is 2.350" long), 43M made from 45/90 (2.375"), 43M made from 45/70 (2.090").
The 45/70 is short, but works well due to the long neck of the 43M. Throat erosion would be the only concern is 45/70 was used extensively. The rim of the 45/90 and 45/70 is a bit thin (0.070" vs. 0.093"), but after the first firing, it headspaces on the substantial shoulder.
Of course I could just use 45/90 and 45/70 without the tubing and I'd have a bulge (they are typically 0.500", so the bulge is about 0.020"), but again, at low pressures, it will stand up, and you can use aluminum tape for the first firing to get it centred for fireforming.
- cut 1/2 of 17/32" K&S thin-wall brass tubing
- solder to the base of the 45/90, and anneal the case while you're at it. The casehead is annealed, but pressures will be low ~ Springfield Trapdoor
- turn the rim to 0.590" and the base to 0.520" (my chamber is 0.525", but this is all my dies will accommodate), trim to 2.375"
- F/L size
- load with a cast bullet sized to 0.448" (my bore is 0.446").
L to R - Dominion 43 M (is 2.350" long), 43M made from 45/90 (2.375"), 43M made from 45/70 (2.090").
The 45/70 is short, but works well due to the long neck of the 43M. Throat erosion would be the only concern is 45/70 was used extensively. The rim of the 45/90 and 45/70 is a bit thin (0.070" vs. 0.093"), but after the first firing, it headspaces on the substantial shoulder.
Of course I could just use 45/90 and 45/70 without the tubing and I'd have a bulge (they are typically 0.500", so the bulge is about 0.020"), but again, at low pressures, it will stand up, and you can use aluminum tape for the first firing to get it centred for fireforming.
Attachments
Last edited: