Jump to content

Reshaping Magazine Feed Lips

Recommended Posts

Glen's mag anvil works very well. I also made one for myself (works good) but it cost alot more than Glen's.

I made a tool that sides into the front of the mag so that the feed lips can be shaped all the way to the front of the mag. Any tool that only comes up through the mag will not be able to completly shape the lips.

I am not slamming Glen's mag anvil, it' well worth the price. Your Thompson may be less sensitive to mag imperfections than mine.

Link to comment
Share on other sites

Magazines are, of course, a critical component of the feed cycle any automatic firearm. When re-forming or straightening feed lips you need to insure the gap at the top opening is the correct radius (.22), width (.55-.56), and is centered on the body and that the distance from the top of the magazine to the edge of the catch hole is correct (2.303). The latter is more difficult to check without a gauging set up of some kind.


Whenever a gun comes to me for service, I always suggest that the customer send any magazines he intends to use for gauging and adjusting. It is never fun to send out a proper gun only to have it hang up because of a faulty magazine.


Link to comment
Share on other sites

The measurements can be gotten from the prints and most of the feed lip configurations can be checked with “normal” measuring tools and common sense and skill. The relationship of the lips to the mag catch hole can not be measured accurately with out a fixture, gage or set up . I am not aware of such for sale; I use a set up on the surface plate and height gage.


One must be careful adjusting the lips as this can have a dramatic effect on the relationship of the mag catch hole to the radii that position the cartridges in the magazine (measured from the top of the magazine to edge of the catch hole). If this distance and radii are not correct, performance will obviously suffer.


Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...