Re: How much powder is practical for 45-70?
Posted: Mon Jun 08, 2020 7:15 pm
Not for a 45-70, but here is some relative numbers of velocity vs Swiss 1.5 powder charge
Bullet always seated over a 0.060 LDPE wad to same depth such that the bullet seated in the lead snug, not really crush:
40-72W bullet: 440 grain EPP ( Elliptical Paper Patched)9+1 ww/lino. Brass 405 Hornady full length, F150 LP thru .007 tgt paper
Powder chg Ave velocity E.S. S.D.
77 grains 1347fps 42fps 17
80 1374 16 7
82 1381 23 11
83 1392 24 8
84 1392 22 9
85 1393 12 5
40-65 bullet 371 DDEPP(Dual Diameter Elliptical PP) 9+1 ww/lino WW brass F150LP thru 0.007 tgt paper
74.0 1396fps 12fps 4
74.5 1403 11 5
75.0 1407 15 9
76,0 1419 16 6
Also, perhaps interesting: 40-65, Same "371 DDEPP bullet, but 16+1 lead/tin
74.5 1388 21 9
Note, this is a rough test with only n=5 shots per .
Was interesting that I hit a sweet spot on the 40-72 where charge wt from 83 to 85 grains gave essentially the same velocity.
Note, though the lower S.D. for 85 gr. I settled on 85 gr for this rifle/bullet.
Now I have a DDEPP bullet for this rifle. Looking good with the85 gr charge.
I settled on 74.5 gr for the 40-65 load. It has shot Very well at all distances starting with 5 shots in 0.66" at 100yds.----when I can do my part.
beltfed/arnie
Bullet always seated over a 0.060 LDPE wad to same depth such that the bullet seated in the lead snug, not really crush:
40-72W bullet: 440 grain EPP ( Elliptical Paper Patched)9+1 ww/lino. Brass 405 Hornady full length, F150 LP thru .007 tgt paper
Powder chg Ave velocity E.S. S.D.
77 grains 1347fps 42fps 17
80 1374 16 7
82 1381 23 11
83 1392 24 8
84 1392 22 9
85 1393 12 5
40-65 bullet 371 DDEPP(Dual Diameter Elliptical PP) 9+1 ww/lino WW brass F150LP thru 0.007 tgt paper
74.0 1396fps 12fps 4
74.5 1403 11 5
75.0 1407 15 9
76,0 1419 16 6
Also, perhaps interesting: 40-65, Same "371 DDEPP bullet, but 16+1 lead/tin
74.5 1388 21 9
Note, this is a rough test with only n=5 shots per .
Was interesting that I hit a sweet spot on the 40-72 where charge wt from 83 to 85 grains gave essentially the same velocity.
Note, though the lower S.D. for 85 gr. I settled on 85 gr for this rifle/bullet.
Now I have a DDEPP bullet for this rifle. Looking good with the85 gr charge.
I settled on 74.5 gr for the 40-65 load. It has shot Very well at all distances starting with 5 shots in 0.66" at 100yds.----when I can do my part.
beltfed/arnie