Gunco Forums banner

Resizing a Barrel

739 Views 7 Replies 2 Participants Last post by  Rhino_66

What's involved in shortening a barrel? I understand that the barrel must be re-crowned, correct? What kind of tools are involved? The barrel I have in mind isn't an AK barrel but the process could possibly be applied.

I have a 1911 barrel that I want to shorten for a commander sized build I'm doing. Instead of spending $150.00 - 200.00 on a brand new commander barrel, I was wondering if I could simply have this extra full sized barrel I have sitting around just shortened by 3/4" and recrowned. I know some companies sell chopped barrels - has anyone used these and can offer up some advice?

1 - 4 of 8 Posts
The important thing is to make sure the muzzle is square. There isn't a whole lot of barrel thickness to crown on a 1911, but irregularities do influence accuracy. If you can cut the barrel square, you can crown it yourself with a big marble and some bore paste. I saw a guy cut a barrel with a pipe cutter. BAD, BAD, BAD IDEA! Fortunately he crowned the barrel to get rid of the restricted tip.

Ideally you should have a lathe for barrel work. If you are extremely meticulous, you can do amazing work with a hacksaw and file. You could use a pipe cutter, but ONLY to mark a line where you want to cut.

It depends on the barrel that you want to shorten. Most 5" 1911 barrels now have a thicker section around the last section of the muzzle. The thicker chunk is what locks up with the barrel bushing. The rest of the barrel is a slightly smaller diameter which allows some clearance when the barrel tips during cycling of the action. This feature has evolved because of accurizing of the 1911 with tighter bushings. Older barrels are pretty much straight and the bushings are relieved to clear during cycling. Without this provision, the tight bushing will bind because of the angle of the barrel. This can also break the fingers off of "fingered" bushings.

If you have a barrel that has the larger muzzle diameter and you cut the barrel short, you will lose the thick section that engages the bushing. There will be a bigger gap between the barrel and bushing. The pistol will function fine, but accuracy will SUCK!

If the barrel is a constant diameter, you should easily be able to shorten it without functionality or accuracy problems. You may need to do a little more smoothing of the bushing, but that's easy.

If your spare barrel is already profiled, you would be better off ordering a new barrel and turning a new profile on it yourself. Another option would be to shorten the profiled barrel and then buy an accuracy bushing with a smaller hole and ream it out to fit the diameter of the barrel. Then you'd just need to relieve the bushing so the barrel can tip without binding.

EDIT: I HIGHLY recommend you get a copy of The Colt .45 Automatic / Shop Manual Volume I by Jerry Kuhnhausen. This manual explains damn near everything you need to know about the function of the 1911 and how to troubleshoot or gunsmith one of them.
See less See more
If you have a drill press, try this.

Find a section of aluminum or brass rod that will fit inside the barrel with minimal play. Thread the rod to whatever diameter thread is close. Drill a hole in a plate and tap it to match the threads on the rod. Punch a hole in a piece of sandpaper and slide it down over the rod. Slide the barrel down onto the rod and start twisting the barrel. This will start squaring up the barrel and cleaning off the burrs from cutting. Use progressively finer paper to get a clean muzzle.

After that, just crown it with the big marble and bore paste.

As long as the rod is perpendicular to the plate, the muzzle should come out fine.

Punching a hole in a piece of sandpaper and placing it between the barrel and receiver of a FAL is an easy way to sand the barrel shoulder if the barrel is undertimed.
Yep, I mean a big ole' glass marble. I think one about 1" would be a good size.

You can use a chop saw. The thin wall of the barrel will cut like butter.

Because of the large bore of the .45, a small grinding stone or ball would be less than ideal. A target crown is 11 degrees, so that's the angle I'd shoot for. At least try to keep the crown shallow.

If you can get the barrel cut in a lathe, you could easily crown it while it's in there. Basically the crown is just a chamfer, so it can be done in about 10 seconds on the lathe.

Or, while the barrel is in the chuck, you could just swab some bore paste on the marble and push it against the muzzle. You need to rotate the marble occasionally to keep from grinding a ring into it.

I wouldn't try to do the crown with a Dremel. I cleaned up the muzzle of one of my FAL barrels by using the spherical grinding ball, though. I twisted it by hand and kept checking the progress. It took about 30 minutes to get it the way I wanted it. I highly recommend The Simpsons as a time killer while doing this. I also recommend The Simpsons while cleaning your firearms. It seems to go quicker.
See less See more
Co7t said:
One more question - If I did shorten a barrel that had a taper, would accuracy still be affected if the barrel is fitted tight to the bushing and bushing to slide?
If everything is tight, it should be accurate. As long as the bushing doesn't bind on the barrel when the slide moves, it should function reliably. You'll have to dress the top of the bushing at the front, and the bottom of the bushing at the back to clear the barrel.
1 - 4 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.