March 8, 2025

The 45-70 and SR-4759

SR-4759 is a discontinued powder and I have some.

It was appreciated for reduced loads in the 45-70.

The original 45 70 load (refered to as 45/70/405) was 70 grains of black powder under a 405 grain bullet. This produced a velocity of 1350 fps.

There was also a reduced load 45/55/405 that gave 1150 fps.

My interest with SR-4759 is to produce similar velocities.

My Lyman 50 handbook shows these loads:

330g lead 26.5 to 28 grains  1454 to 1533 fps
385g lead 24.0 to 26.5 grains 1252 to 1426 fps
405g lead 24.0 to 26.5 grains 1258 to 1415 fps
I am tempted to try 24 grains under a 350g Berry's plated bullet and see what I get. This would be an "intermediate" load, with more velocity than I would get using Trail Boss or 700X.

I have some pages from a very old Lyman Cast Bullet handbook that show less potent loads for these bullets using 4759, but they require a polyester felt patch to hold the powder near the primer and I would prefer not to deal with that.

When I run out of 4759, then what? My Lyman 50 shows some loads with Varget. Believe it or not, 42 grains of Varget under a 405g lead bullet gives 1258 fps -- the same as the SR4759 load!! I will have to try these and see what I get.


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Tom's Computer Info / tom@mmto.org