#23514
Smoke4320
Participant
  • Silver
  • ★★
  • Posts: 11
  • Comments: 140
  • Overall: 151

Goodsteel;n1329 wrote: My own tests with 35 caliber in 14 twist have shown that the RPMTH is lower with larger cartridges. I was only able to get to 2600 FPS with my specially designed 35XCB cartridge and bullet. Furthermore, I have found not one single person who can demonstrate real linear accuracy with 35 caliber in that twist rate.
Add to that the fact that 50 BMG with a 15 twist barrel has trouble running into the RPMTH at 2400FPS or less, and you begin to get the picture.
Bigger diameter, more massive bullets are going to be effected by centrifugal force much sooner than the same shape bullet in a smaller caliber.
This is not too hard to understand as everyone knows it’s a lot easier to stay on the merry-go-round if you stay in the middle rather than out on the edge where centrifugal force can send you flying.
Same thing with our bullets. We do not know what the centrifugal force gets ahold of, but whatever it is, it’s on the surface of the bullet, and the surface of a 35 is a lot further away from the center-line of rotation than the surface of a 30 caliber is.
Therefore, bigger caliber= lower RPMTH, and that’s why I recommended a slower twist rate for the speed you desire.

Great splaination there 🙂 easy to understand with the analogy

© 2017 Goodsteel Forum. Designed by Covalent Designs, LLC.