Hello,

Has anyone ever successfully loosened and re-adjusted the barrel adjusting sleeve. If so what did you do to loosen the sleeve and how did you hold it w/o ruining it? I am trying to put a high numbered (1.3 mill) barrel on my low numbered 254XXX receiver but need to get 1/8 turn more on it for a proper match up.

I was able to get it to suck in a lot of penetrating oil w/ a little heat from a butane torch but it's frozen on pretty well.

Any thoughts are greatly appreciated

Thanks, Joe

There is a discussion of fitting a model 12 bbl on Nu-line guns webpage.

Model 12 bbl fitting

I have a tool made by Menck for turning the Model 12 adjusting sleeve. I've been using it for over 15 years. It looks like a double end box wrench, one end for 12 ga, the other for 20. Brownells use to carry them but I can't find a listing. Maybe they show up on Ebay or the used market.

I don't see them listed anyplace either. Apparently now that working on Model 12's has fallen a bit out of vogue, nobody's selling them anymore.
You might try contacting Tom Menck directly ( in Ralston, Nebraska iirc.) He might have some old stock.
Lacking that, I have one that I made up in school some 40 years ago (about the same time Mr. Menck was there) and could email you a pic and quick dimension drawing if you wanted to make one. Interestingly, several of Mr. Menck's earlier tool offerings bear strong resemblance to some that we made as shop projects. And good on him for offering them commercially and basing a successful business on them.

You trying to turn the rec'vr extension onto a replacement bbl,,or (un)screw the small adjustment ring that tightens the TD feature?

The latter should unscrew easily by hand once the toothed locking block is back away from it (remove the small screw).

The receiver extension is another matter and requires a bbl vise to hold the bbl securely first off.
Then a special wrench to remove the extension.
The wrench I use is a simple flat steel bar w/ a chamber dia plug on one end and a similar plug to fit into the magazine tube opening of the extension just below it.


The plugs must both be a snug fit to avoid deforming the extension.
The wrench pivots around the plug in the chamber. Different size chamber and mag tube plugs (w/adj location) can be made so the wrench can be used for the different ga M12's (&97) and even the M42.

A handle length of 15 or 16" is good. A sharp strike w/a hammer on the end of the handle will break the extension free when taking them off. The leverage of the handle is more than enough to ease them into position when installing them.

Thanks for the advice. However since this was a one time project I did something you'all might think ghastly. I removed one of the jaws in my 4 jaw chuck. Used a bull nosed center in the tail stock and grabbed the barrel assembly w/ the remaining three jaws. I also supported the outside muzzle end of the barrel w/ a three point spider on the outside end of the lathe head. I then used a dial indicator to get it running true. Doing the math indicated that a .00625" cut is 1/8 of a turn for the 20TPI threads and I made a .005" for the first cut. Still too tight so I cut .002" more and w/ a little polish using 320 grit emery cloth it fits up perfectly. Blue lay out fluid just scuffs when checking the final lock-up.
This only worked because the barrel was too long. If it was too short I would have to have gone w/ something else.

I appreciate the advise though.

Joe