...does a 12ga barrel need to be fitted with screw-in chokes? I've got an old Savage single barrel that I want to use as a trainer, you know, re-stock, stone/polish/re-blue. A learner gun....

MKane160

I haven't installed screw in chokes in ages, but the tooling I have on hand, for Win Choke type tubes, requires a 12 guage barrel to have an OD of .840. That would give a minimum wall thickness of .0175. No room for error!

Look here:

http://www.brownells.com/UserDocs/Miscellaneous/Screwinchokeinstallation.pdf

If anyone needs standard choke tooling for 12 gauges, PM me, these are for sale...

quote:

does a 12ga barrel need to be fitted with screw-in chokes?

Only if you want screw in chokes or if you have sawed off the barrel to shorten it...(and not less than18 1/2")

Scott Carlson of www.carlsonchokes.com has all the info you need...check his website. He's in Atwood Kansas.

He does a lot of this.

Vapodog, you missed the first part of the question:

How much wall thickness.....
...does a 12ga barrel need to be fitted with screw-in chokes?

quote:

Originally posted by James C Scott:
Vapodog, you missed the first part of the question:

How much wall thickness.....
...does a 12ga barrel need to be fitted with screw-in chokes?

yes I did.....

I could calculate the tangential tension and the axial tension with muzzle pressure and inside diameter. The wall thickness in the thread groove must suport the axial, and the average of the thread groove and peak must support the twice as big tangential tension.

But my guess is that the real trouble is when the shot hits the choke, and is not as calculatable.

You're exactly right. I get guns in the shop sporting thin tubes, who's threads are literally beat to death from the constant battering they receive from heavy shot and lack of care. Some of these tubes and their threads have gone so long without proper care, and are so damaged, the tubes become impossible to remove.

Folks need to get into the habit of pulling the tubes from time to time to inspect and replace them as needed, and to clean and relube the threads. If people would do this, the job may last a while.

Mike,
I have had chokes installed by a guy in Amhurst MA. and his information says he can do a 12 ga with thin wall tubes with as small a muzzle diameter as .805" and a max bore of .730, he can install Truelock chokes with an outside diameter of .825 and a max bore of .736.

If you go with him, join a shotgun web site called shotgunworld and you can get the work done at dealer price at $35 for the choke installation and $17 for the chokes.

Thanks, Chic. Uh, the guy's name is....?

MKane160

Well the wall thickness question seems to have been covered pretty well but I'm still curious why you think it's necessary.
Since this is "a trainer" why not simply adjust your shooting distance according to pattern? IMHO way too many people take the marked choke at face value without actually patterning their gun.