Creased Cartridge

[Viktor]

I bought a new S&W1911 and ran a box of Win. FMJ rounds thru it. All the cartridges have a sharp crease on the bottom edge of the base like they are really being slammed by the slide. Is this a head spacing problem? The pistol functions fine so far and I don't reload, but is this a serious problem?

[twin oaks]

Hi Viktor, welcome to the forum!
Some pics would be helpful to illustrate the problem, but from your description, I'd say check the breechface for irregularities, or tooling marks (or look to see if the crease is shaped like an extractor claw's nose--depends on where the crease is). S&W's got a good rep, but they are production runs and a few do occasionally get by the Q&A folks. If you're not able to post pics, mark your rounds in the magazine to indicate 'up', and then describe where the crease is, in relation to 'up'- maybe put a stripe along the top of the case with a Sharpie or the like.
You've come to the right place to learn all you ever want about the 1911.

[log man]

Viktor,Look at your breach face and you will probably see a machining flaw. The breach is cut in several operations, this step is fairly common,it can be eased a bit with a small file or you can stone by hand to even it out. When the cartridge goes off the same pressure that pushes the bullet out is also pushing against the breach and it is considerable. This is why you're seeing this crease. It's really quite common, and doesn't normally require addressing. :)

[gottripletsNC]

I'd be leary of any stoning or filing on the breechface, only way I would stone or file the breech is if I saw a very noticeable hump or burr etc. The breech is at a very controlled angle which plays an important role in the controlled feed of ammo. There is room for play but if other areas are out of spec in the slightest, and you start messing with another area, that might be enough to send the gun out of spec enough to cause feed problems. Pics would be a very good idea before you started anything like that.

[Viktor]

The case base creasing is apparently happening on recoil; I hand cycled several rounds and there was no damage. The mark occurs across from the extractor and there are faint machine marks there. The cartridge rim barely fits in the breech face and will not sit completely flush with it when forced in by hand. There were no failures to feed or extract so I'll keep shooting it, I really like this pistol. FYI: there was a heavy string of burrs 5/8" long on the slide contacting the frame, which I took off with some 400 grit. I hate to see this from S&W. Thanks again.

[brownie]

...The mark occurs across from the extractor and there are faint machine marks there...

It is not uncommon on S&W 1911's for there to be a small ledge at this position on the breechface. Pictures would be useful to confirm that this is the case. It doesn't usually hurt anything, but it's easily removed with a scraper, such as the disconnector notch scraper that Brownells sells.

--Bill