Best Way to Check Twist

[dondford]

I have a 220 Swift AI built with a Douglas blank I bought at a gun show; if I ever knew the twist I've forgotton. What is the best way to determine the twist?

Thanks,
D

[philip]

Wrap a patch around a cleaning jag, put a mark on the rod by the base and slowly push the cleaning rod through the barrel counting the rotations(twist).


I should be more specific.............

Place the cleaning rod into the rifling of the gun.

Put some tape on the shaft of the cleaning rod at the back of the reciever.

Slowly push the rod in until it makes one revolution.

Mark the rod again at the back of the reciever(exactly where you marked it before), then remove the rod and measure the distance between the marks.

This will give you your twist......


Clear as MUD?????

[Eagle_view]

I do it this way;
I put enough cloth on a jag so you can feel the rod turn with the rifling, run the rod and Jag into where the rifling has a good hold on your patch. I mark the rod with a Sharpie marker at some defined point on the action; I then measure back on the rod 12" and mark that. The masking tape is a good idea. Often I will use the top forward corner of the bolt receiver notch as my marking point. I run the Sharpie along the top of the rod making a single line on center

I then push the rod through to the 12" point that was marked, counting the rotations ( the number of times the line comes up) until I get to the action spot again. Don't be surprised if they are not exactly even.

You might have a barrel that is marked 1-12" and find that it is reallly eleven and one half rotations to a foot.

It is a good thing to check all your barrels and know what the real twist is.

Lowell

[Ackman]

When you push something through the bore, it unscrews. PULL a brush from the muzzle back. A little piece of masking tape on the rod, at the rod guide, and mark the top. PULL until it's made one full turn, then measure from edge of tape to rod guide. Very simple and quick.

[RePete]

Originally Posted by Eagle_view

You might have a barrel that is marked 1-12" and find that it is reallly eleven and one half rotations to a foot.

Lowell

HUH???

[william t. oviatt]

Double HUH! I never seen one of those!

I Think I know what you thought you said, or I think you knew what I thought you said "Eleven and a half rotations to a foot.." It's either in the rotations or whose foot, I'm not sure which, but one of them is off somewhere. LOL
Bill

[montdoug]

So does this mean there is now 11 1/2 inches in a foot . It must have something to do with the "New Math" huh?

Actually I understood it completely, is that a bad thing?

[philip]

Eagle View,

I use a sharpie on the masking tape, makes it easier to see....

I guess i left that part out?????

[larryinIA]

is caused by button riflers. When they are button rifled, for some reason...they come out approximate. A lot of mfrs have a disclaimer that they are within a turn or half turn either way of what they are advertised. So, a foot is a foot, but a 12 twist, may be 11.5, or 12.5 twist...

Is that better?

[Bayou City Boy]

I'm with Ackman....

PULL a patch from the muzzle end back out of the barrel and the jag will stay tight on the rod and give you a correct distance for one revolution of the rod.

I draw a straight line down the rod with a marker. With this line on top in reference to the receiver, I place tape around the rod marked with a pencil line on it using a reference point on the receiver where I begin pulling the rod and patch with the straight line on top.

With the tight patch, the rod will turn as you pull it. When the line down the rod comes back up on top again - one twist - I again mark the rod with tape and a pencil line on the tape using the same reference point on the receiver that I used to mark the first piece of tape.

The distance between the two pencil marks on the two pieces of tape is the bore twist rate.

Pushing the rod through from the breech end allows the jag to possibly come loose and screw up the math...

-BCB