View Full Version : 1911 40 S&W

12-25-2010, 7:51 AM

Can I build a 1911 40 S&W out of a 1911 45 ACP pistol? What is it going to take to do it? what kinda of barrel I can replaced it with.


12-25-2010, 10:21 AM
I'm pretty sure you are going to have to replace the slide

edit: slide meaning you need to get another slide with all the 40 s&w internals in it to make it work.

12-25-2010, 10:38 AM
Slide, barrel, recoil spring, not sure about the feed ramp? After all, hope it would feed and eject properly + doesnt kill or injure you and others. Personally, I wouldnt do it. With all the time and money you'd be better off buying one in 40 cal.

12-26-2010, 10:32 AM
I've done several caliber conversions on a 1911 frame. The first thing you'll want to do is change the ejector. A .38 Super ejector will work. Actually, I'd just remove the ejector and leave it out for now. You'll need to check slide to frame fit and don't need the ejector to get in the way.

You need a slide assembly in .40 cal or 10mm to accommodate the smaller diameter of the case. I've been told Springfield Armory slides in .38 Super and .40 cal have the same breech face, but I've never checked.

The sides of the breech face and the extractor hold the shell case in place for correct feeding. If the breech face is too large, the case rim could miss the extractor and not feed properly.

The type of barrel you use depends upon the type of frame you have. If you have a typical 1911 frame for a .45 acp, you'll need to get a stock .40 cal barrel, but you may have feed ramp issues. If your frame is milled out for a ramped barrel, you can get a ramped barrel and eliminate feed ramp issues, plus have a fully supported chamber.

I've built different caliber 1911's with both types of frames. Just make sure you get the proper barrel because there are different types of ramp cut frames.

I bought a recent production Springfield Armory .38 Super to build into a .40 cal. Springfield uses fully supported .38 Super barrels, so all I would need to do is fit a ramped .40 cal barrel. Best case scenario was that the .38 Super slide would work with the .40 cal. If not, I have a Caspian .40/10mm slide as well as a Para Ord .40 cal slide on two other guns. I've also been told that .38 Super mags will work with .40 cal, but I haven't checked that out either because I went out and bought a Glock 22 and solved my .40 cal problem.