Twist rate-again

[gjgalligan]

I wanted to determine the twist rate on my .223 & .308.
Took the .223 barrel and clamped it into the vise. Put the jag on with a patch. Patch was too big and would not go in barrel so i played around with that till it fit.
Seems as though the cleaning rod handle spins freely UNTIL you start to push it through the barrel!
All I got was a cleaner barrel and a bent cleaning rod. Didn't even try the .308 I was so flustered.

[OldSchoolRanger]

In the FAQ's:

What are the rates of twist?

.223 1 in 12", late models are a mix of 1:9"/1:12",  2007 and later Marlin produced barrels are 1:9", use instructions below to determine the twist rate.

.308 1 in 10"

http://www.gboreloaded.com/forums/index.php/topic,26264.0.html

Instructions on determining the rate of twist:

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".

also:

http://www.gboreloaded.com/forums/index.php/topic,219757.msg1099197704.html#msg1099197704

It is important to use the correct size jag and patch.

[yukondog]

308  1 in10

[gjgalligan]

I see where I messed up, I tried doing it when pushing it in!
I had read the the above posted instructions a couple of months ago and should have reread them before attempting this at home!
I'll do the right way later tody.
 
Thanks.
 
Still would not work with brand new jags so I used new bore brushes.
Did each one 3 times to confirm.
1/12 for the .223
1/10 for the .308

[OldSchoolRanger]

I see where I messed up, I tried doing it when pushing it in!
I had read the the above posted instructions a couple of months ago and should have reread them before attempting this at home!
I'll do the right way later tody.
 
Thanks.
 
Still would not work with brand new jags so I used new bore brushes.
Did each one 3 times to confirm.
1/12 for the .223
1/10 for the .308

Glad you worked it out.

[gcrank1]

You are certainly not the first to have trouble with the old tight fitting patch. The shallow rifling nowdays is the culprit; the old deep cut rifling spins it easily.