What twist should a 45 be for shooting conicals ?

[freddogs]

:gulp:  The title explains pretty much what I want to know. I was thinking of getting a 45 barrel for my thompson Hawkins. I'd like to shoot conicals with it. Is anyone out htere doing it now ?

[Jack Crevalle]

Well according to these guys it should be 1:28.

http://www.prbullet.com/s45.htm

[Underclocked]

Depends upon more than just caliber, the groove width and depth make a big difference as well as the length of the conicals you are going to shoot.

My White 1 in 20 will shoot almost any conical well with some going far less than 1 moa groups.

My 209x45's first barrel with 1 in 20 wouldn't shoot ANYTHING well.  The current 1 in 28 barrel still doesn't seem to like conicals but loves the 350 grain White PowerStar sabot'd bullets.

I've about decided the performance of the barrel depends upon which spell was cast upon it.   :eek:

[Snowshoe]

Each rifle will tell you what it likes. I had a Investarms Hawken in .45 , [1 in 48"], that shot the 240g  Maxi very well. I think the 1 in 48" is about the minimum.

[dbm]

For a 70 grain charge and a 530 grain elongated bullet, Joseph Whitworth established in the 1850's that 1:20 twist was required. 1:18 may be better for long range though (900yds+)!  :wink:

David

Long Range Muzzle Loader

[msdh]

Underclocked said it pretty well.  Grove depth and width is very important.  My .45 calober White is a 1-20 and its a tack driber in bullet weight from 350 - 460.  Normally the faster twists are partial to longer bullets.

[MAINER1234]

I WOULD GET A 1:48 AND THE BEST OF BOTH WORLDS .

[Black Jaque Janaviac]

It depends on the bullet design.  .45 caliber pistol bullets are going to require a different amount of spin than .45 caliber rifle bullets.

Generally, short bullets like less spin, long bullets like more spin.  

To increase spin, you either increase rifling pitch (hard to do) or increase velocity.  

Other things like the shape of the bullet go into play.  Some bullets that are rear-heavy might need more spin than something that is front heavy or balanced.

Anywhere from 1:20 to 1:30 would be about right.

Green Mt. now offers Hawken drop-ins for .45 fast-twist.  They are 1:30 pitched.  I asked why not 1:20.  They said their testing found that this pitch worked best with sabots.

[mamaflinter]

The 1:48 is a compromise twist. It is fast enough to stabilize a conical and slow enough to stabilize a roundball with reduced charges.

Alot of things should be considered as Underclocked stated. But you can get by with a 1:48.