View Full Version : Building a 1911 pistol

Joe Portale
December 7, 2001, 09:45 PM

I am currently getting ready to build my own 1911 pistol. (One of those keep me from playing in the street, winter projects).

Is there any differences between in a 10mm slide, or can I use a standard 45 caliber slide?


James K
December 8, 2001, 12:07 AM
The 10mm cartridge base is smaller than the .45, so the 10mm slide is different at the breechface, and the extractor is set up differently. I don't have one in front of me, but I think the ejector is different also, meaning the ejector cut in the slide is different.


Joe Portale
December 8, 2001, 09:51 AM
Thanks Jim,

You are correct about the extractor. A 10mm (9mm, 38Super and 40) have a flatter nose and deeper hook cut that what is found on a 45. The ejector is different also, if I remember correctly, the angle is lower to capture the small cartridge rim.

The breech face being different is a new one on me. If the barrel and cartridge are aligned properly, will that make that much of a difference? I know a couple of guys that built 357Sigs on a government platform and they never mentioned anything about the breech face.

FWIW, I have ordered the Kuhnhausen books on the 1911. The second book covering custom guns. Does anyone know if the breech face topic is covered in Book 2?

Thanks. More questions to follow as this project proceeds. ;)

James K
December 8, 2001, 11:55 PM
If you have a slide handy, look at the breech face. On both sides there are shoulders that fit up against the barrel and partially surround the case head. At the top, the barrel hood fits into the gap which extends all the way to the top of the slide. The gap obviously has to be sized for the case head. If it is too big (.45 slide for 9mm), the case cannot be held by the extractor; if it is too small (9mm slide for .45), the slide will not go into battery.

You will see that those shoulders have a circular cut which has to be the case head size and has to be concentric with the barrel.

In addition, when the ejector is made higher or further in, there has to be a corresponding change in the milling of the slide to fit the new ejectory.

I have not checked Kuhnhausen's book but I think he must mention someplace that slides are not all the same for all calibers.


Joe Portale
December 9, 2001, 03:27 PM
Thanks Jim,

A couple of hours after my last post, my brain decided to kick in. DUH! Of course the shoulders on the breech need to be sized different..double DUH!

Thanks for the input.