Rifle twist ?

Birddog 1 · Post by **Birddog 1** » Wed Jul 15, 2009 1:36 pm

I have done it 3 times and keep comming up with 18.5" for 1/2 revolutions on the old cleaning rod pulling from the breach to the muzzle..... What would my rate of twist be? This is in a new Marlin LC45 ? It just doesnt seem right that would be 37/1

J Miller · Post by **J Miller** » Wed Jul 15, 2009 1:43 pm

Birddog 1 wrote:I have done it 3 times and keep comming up with 18.5" for 1/2 revolutions on the old cleaning rod pulling from the breach to the muzzle..... What would my rate of twist be? This is in a new Marlin LC45 ? It just doesnt seem right that would be 37/1

If it is a new recently manufactured Cowboy it will have a 1-16" twist.

If is's an older non Cowboy I think they had 1-38" twist barrels.

I've had fits calculating rifling twist with cleaning rods too. Never could get it exact.

Joe

deerwhacker444 · Post by **deerwhacker444** » Wed Jul 15, 2009 1:54 pm

1-37" is pretty dang close to 1-38" twist. I'd say you measured it pretty accurately.

Birddog 1 · Post by **Birddog 1** » Wed Jul 15, 2009 3:37 pm

OK then I have a 1/38 twist.... what weight bullet will this twist handle?

TIA Birddog 1

AJMD429 · Post by **AJMD429** » Wed Jul 15, 2009 4:19 pm

Here's some good stuff on twist rates (all calibers) -
Twist Rates - LASC - http://www.lasc.us/Brennan_2-3_Twist.htm

and here's a really good article specific to heavy bullets in the .44 Mag from the Marlin 1894
(the site has many other articles you can troll for which ought to cover the .45 Colt) -
Heavy 44 Mag bullets in the Marlin 1894 - http://www.lasc.us/Fryxell44OverWeight.htm

Post by **Chuck 100 yd** » Wed Jul 15, 2009 7:54 pm

If it is a Cowboy Comp. rifle. It is properly rifled to shoot light for caliber bullets. CAS shooters go through a lot of lead and lighter bullets are much easier on the wallet and less recoil means faster times.

J Miller · Post by **J Miller** » Wed Jul 15, 2009 8:01 pm

Chuck 100 yd wrote:If it is a Cowboy Comp. rifle. It is properly rifled to shoot light for caliber bullets. CAS shooters go through a lot of lead and lighter bullets are much easier on the wallet and less recoil means faster times.

Mine is a 2005 Vintage Cowboy Comp. It has the 1 turn in 16" twist.
Heaviest I've ever fired in it was 300gr at 1300 fps. All the holes were straight through the target.

Joe

geobru · Post by **geobru** » Wed Jul 15, 2009 9:25 pm

According to the Greenhill formula, the longest bullet that will stabilize is .806" long. I assumed 1:38 twist, a diameter of .452, and velocity less than 1800fps.

gb

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