Twist rates

[Steel Horse Bailey]

I found out today that my Sharps repro has a 1 in 18" twist rate.  Is that suited better for light, medium or heavy bullets?  When I bought the rifle, I also bought 3 boxes of Remington 350 gr. jacketed bullets to use for reloading until I could find empty brass 45-70 in my area.  Shooting those bullets was a great pleasure because of the accuracy I got.  I had big hopes.

After they were all gone, I'd found some 405 gr. and some 510 gr. lead pills.

I've NEVER been as accurate with any lead bullets as I did with those jacketed ones!

Any ideas out there as to bullet weight I should work with?

Thanks     SHB

[Hemlock Mike]

Typically, heavier slugs need a faster twist to stabilize.  Ol' BP loads however always seem to shoot with slower twists.  Go figger !!!!

Maybe a little load data will help us out.    I shoot 32gr of H4198 under 340 and 405 grain cast with good results in Pedersoli rifles.  I'm leavin' the muzzle at about 1350 Fps.

Mike

[john boy]

SHB, here is a formula to play around with.  Each field can be calulated separately if values are in the other 3 fields.
http://www.uslink.net/~tom1/twistrate.htm

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[Silver Creek Slim]

According to what I have read, that twist rate should be fine for 500+ gr boolits. Don't ask me to tell ya the source, cuz I don't remember. 

Slim

[Delmonico]

Most likely someone figured it with the Greenhill formula.  I'll try to drag it out of my notes tonight.

My Pedersoli Sharps has 18 to 1 twist and it shoots the Lyman 457122 fine, this is a 330 gr HP.  The 500 gr RCBS-500-BPS shoots at little better but I weigh the 500 grainers to 1/4 grain and the 330 Hp I only weight to 1/2 grain since is is a hunting bullet.

SHB, one of these next evenings I'll give you a call and I'll pass on what I can, I just hate to type that much.

[Four-Eyed Buck]

1 in 18 is about the norm for 45-70's. I believe that was what the Trapdoors had as well. I shoot 405's in my BC and they do pretty well. I use smokeless ,but keep the speeds down in the BP range. XMP-5744 at 18.5g, the 405's, a CCI BR-2 primer in either WW or Rem. cases. Out of the BC's 32"er, gives 1299fps............Buck

[Delmonico]

1 in 18 is pretty much the norm for modern replica single shots, but a lot of the originals had slower twists.  I'll check some referances when I get home, just for fun and learnin'.

[Steel Horse Bailey]

Thanks, y'all.  I'm not too good at the math involved, but I think if I can A:  get a good load and B:  get a baseline at 100 or 200 yds I'll be on the right track.