As listed in the FAQ's on the main Handi page: -g
What are the rates of twist?
Duce
posted December 28, 2003 07:09 AM
.17 HMR 1 in 9"
.22 LR 1 in 16"
.22 WMRF 1 in 16"
.204 Ruger 1 in 12"
.22 Hornet 1 n 12" (original H&R pre '87 1:16"?)(or 1:9" for late production)
.223 1 in 12", late models are a mix of 1:9"/1:12", 2007 Marlin produced barrels are 1:9", use instructions below to determine the twist rate.
.22-250 1 in 14"
.25/06 1 in 10"
.243 1 in 10"
.270 1 in 10"
.280 1 in 10"
.308 1 in 10"
.357 Mag 1 in 18¾" or 1:15½"
.357 Maxi 1 in 18¾"
.35 Whelen 1 in 16"
7mm-08 1 in 10"
7.62x39 1 in 9¾"
7x57 1 in 10"
7x64 1 in 10"
7mm Rem Mag 1:9.5"
.30/30 1 in 10"
.30/06 1 in 10"
.300 Win Mag 1:10"
.38/55 1 in 18"
.44 Mag 1 in 38"
.444 Marlin 1 in 38" (original)
.444 Marlin 1:20" (2007 and later)
.45/70 1 in 20"
.450 Marlin 1 in 20"
.45 Colt Carbine 1:16"
.45 Colt/410 1 in 16"
.500 S&W 1 in 18¾"
20 ga. 1 in 28"
12 ga. 1 in 35"
.45 cal Muzzleloader 1:56"
.50 cal Muzzleloader 1:28"
.58 cal Muzzleloader 1:66"
Current production .223 Rem barrels are being made by Marlin with a 1:9" right-hand twist, lands are .219"-.221" and groove is .2240"-.2255". Right now they still have some 1:12" Superlight barrels. (as of 7-5-2007)
How to determine the rate of twist of a barrel....
It's real easy to determine what the rate of twist of a barrel is, all you need is a tight fitting jag and patch on the end of a cleaning rod. Insert the rod in the bore from either end. Push the rod into the bore until you almost reach the other end of the rifling. Wrap a flag of tape around the rod where it enters the chamber or muzzle. Withdraw the rod slowly making sure the rod can rotate freely following the twist of the rifling. When the tape flag has rotated exactly one full turn, measure from the tape to where the rod enters the bore, that is the rate of twist. On some rifles with slow twist like the 44mag which has a 1:38" twist rate, use a half turn of the rod and double the measurement, ie: 2x19"= 38".
