Best way to figure out barrel twist?

[40X Guy]

What is the easiest best way to figure out the twist rate on a barrel? I acquired a rifle with a custom Shilen barrel on it, and according to previous owner its either a 7,8, or 9 twist. Its a 6MM barrel, and previous owner does not remember. I have not tried to calculate with the cleaning rod yet, but maybe there is a more accurate way out there?

Frank

 

[RonAKA]

The cleaning rod with a brush is the only accurate way I know of. I just put a strip of masking tape on the rod near the handle, and push it in past the throat. I then use a pen to mark the exact top of the rod, and measure the length of the rod from a hard reference, like the back of the receiver. Then push it in until the pen mark comes to the top again, and measure again. The difference is your twist. If it is a faster twist, you can push it in for two turns, and obviously divide that distance by two.

If is an exact inch twist you will have no problem identifying which one it is.

 

[40X Guy]

RonAKA, thanks for the reply, this barrel is definately an 8 twist. Method works well. I believe the Bore Tech cleaning rods help accuracy also.

Frank

 

[artbosco]

What is the easiest best way to figure out the twist rate on a barrel?

Sinclair’s Simple Twist Rate Measurement Method

If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8 twist barrel.

 

[40X Guy]

Thank you Outdoorsman!, I kind of came up with a way between Sinclair's method you posted and Ron AKA's method. Just wanted to be positive.

Frank