Twist rate for a re-barrel
I have a Ruger #3 chambered in .45-70 that I am planing on re-barreling and chambered in .38-56. I would like to have a twist rate of either 1 in 14 or 1 in 16. I plan on using 250 to 300 grain bullets. Any and all help will be appreciated.
for GOD and COUNTRY
Vet
for GOD and COUNTRY
Vet
0
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i'm not sure what exactly you are asking. if you need to know which twist is better for the 38-56, i would suggest two things, one call the barrel maker and ask them what they think they are pro's. second post this question in the forums at shiloh sharps they have a very good forum for black powder cart. questions. i don't know the exact web address you will have to do a search. 0 -
Mayhaps you could apply the Greenhill Twist Formula:
Twist = (150 X bullet diameter)/(bullet length/bullet diameter)
For a .45-70 this should be okay, since the book I pulled this out of says that the formula works for velocities up to and under 1800 fps.
The thing is, it doesn't seem to factor in bullet weight, but depends upon length and diameter (it assumes lead bullets, I guess.) If you know the bullet length and diameter (in inches, of course) you'll get a number like "Twist = 20.6" or something (just a number I pulled out of thin air) which you interpret to mean an optimal twist rate of 1 turn in 20.6 inches. Hope this helps!0 -
I too, have used Greenhills formula and it seems to work fine. You'll probably get 1 in 15" 
). If so I'd go with the faster twist. (if you can't get the exact one). BTW, I think that was in Hatcher's Notebook IIRC. The best way though, is to find someone shooting or building guns in this caliber and get first hand info. That should make a nice rifle when you get it barreled up.0 -
Come to think of it, IIRC, the 38-55 used a slower twist than that 1 in 18 or so and the 2 cals should be fairly close in velocity, bullet wt etc. 0
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