Rate of twist

BIG.PAUL · 12-10-2009, 07:16 AM

What is the best rate of twist for conicals?

Should the rate of twist change per barrel length?

Should the rate be different for a target rifle versus hunting.

I'm talking .50cal here.

flounder33 · 12-10-2009, 07:44 AM

Mostly the length of the projectile determines what rate of twist is best.

Nimrodder · 12-10-2009, 08:43 AM

If you are talking about a long conical such as a No Excuse or Bullshop conical I would want a rate of twist of 1 in 28" or faster. Some of the shorter conicals such as the maxi-hunters do fine in a 1-48" twist. As far as barrell legth goes I don't think it matters. 3 of my Whites have a 22" barrel with a 1-24" twist and thrive on shooting big, long conicals.

I've also heard some 1-48" barrels shoot the big conicals pretty well but I've never had any luck with them.

lemoyne · 12-10-2009, 11:13 AM

Calculated Bullet length for 1-28 and 1-24 twist

Twist 1-28 Twist 1-24
Diameter Bullet length in inches Diameter Bullet length in inches
.458 1.10 .458 1.3
.450 1.05 .450 1.25
.400 .85 .400 1.00
Twist = 150 X D2/L
Where:
D = bullet diameter in inches
L= bullet length in inches
150 = a constant
This should give you the basics. Lee

cayugad · 12-10-2009, 11:21 AM

It used to be we purchased 1-32 twist rifles for conicals. They shot a good sized bullet with excellent accuracy. But ever since I purchased my Whites .50 with a 1-24 twist and my .45 caliber White I believe is a 1-20 twist, I have mixed thoughts. The faster twist seem to shoot a longer conical with extreme accuracy. The 1-32 does real good with the Great Plains, maxiball, and those kind of conicals.

BIG.PAUL · 12-10-2009, 11:24 AM

That is strange, however my triumph will shoot a 385 maxi ball style conical VERY well out to any distance I want, and that is a 1 in 28 twist. hell if I know!

lemoyne · 12-10-2009, 12:52 PM

BIG.PAUL
There is a lot involved. For one thing there has been a bunch of people saying that TC guns won't shoot conicals. I don't know where that started but I never had any problem getting any TC to shoot conicals, I often went to several western states where we needed to shoot them before my dad died and I always work up a couple loads with them just in case I find a new hunting partner [ I am not fond of driving that far alone or hunting in the mountains alone]. I particularly like the the FPB by Hornady and the 460 gr, they both shoot very well in both my Triumph and my Endeavor, even the old back up Omega does well with them. all 1 in 28 twists. Lee

BIG.PAUL · 12-10-2009, 02:48 PM

Lee, I agree with you. my triumph will shoot great groups with a maxi ball and the right powder. I don't know why, except for the rate of twist, but Dave one of the gunsmiths from T/C told me they desighed all three gun you mentioned were build for sabots.

Semisane · 12-10-2009, 06:59 PM

Hey Lee, I plugged the diameter and length of 300 grain Gold Dots into your forumla, as well as 210 grain Gold Dots and 200 grain XTPs, and the results indicate the ideal twistfor those bullets would be in the 1:38 - 1:40 range. I wonder why no one makes barrels with a twist like that.

I't seems muzzle velocity would also be a factor. Do you have any info as to that?

flounder33 · 12-10-2009, 08:10 PM

I noticed that too Semi. I thought I must be doing something wrong in my cyphering. I sure am relieved you came up with the same answer.
Art