Need advice on a 1911 project

[harley45]

If I understand it correctly the .38 super Colt guns use the same feedramp as the 10mm guns did. I have a 38 super that I converted to 9x23 and so far it is working perfectly. However today I talked to a guy who is shooting 9x23 and 40 s&w from the same 40 caliber breechface. My idea is to get a new slide for my super in 40 caliber and build a dual 10mm/9x23 gun. Could this be done? Anybody ever try 10mm from a 9mm breechface? I wouldn't mind if I have to use different extractors, but I'm not going to mess with this if everybody tells me I'll need different ejectors.
Thanks for the help

 

[stans]

The rim on the 10mm is 0.031" larger than the 9mmx19 and 0.019" larger than the rim on the 38 Super, so it may not fit in the breechface of a 9mm/38 Super slide and if it does, you will need a different extractor as the extractor for 9mm/ 38Super is going to be too tight for the larger 10mm. Also, the slide stop for the 9mm and 38 super may contact the sides of the 10mm bullets in the magazine and prematurely lock the slide. I think a dedicated 10mm slide would be your best choice.

 

[harley45]

That makes sense but what about a dedicated 10mm slide with a 9x23 barel? I know the glock guys do it in their g20s

 

[stans]

Well, I have heard of 10mm guys puting 38 Super barrels in the 10mm slide and getting them to work, so I guess it is possible. The 9x23 rim is smaller than the 10mm, so the fit in a 10mm slide should be ok, reliable extraction may depend on how well the 10mm extractor will grip the smaller rim.

 

[Majic]

Just a question, but would the ejector pose a problem? I know when they developed the .40SW it was said they went with the small primer because the large primer of the 10mm posed a threat of being struck by the ejector when ejecting live rounds on 9mm based frames.
Are the ejectors different for the .45/10mm sized cartridges vs the .40/.38super/9mm sized cartridges?

 

[stans]

As fas as I know, the 10mm, 40 S&W, 38 Super, 9mm all use the same ejector which is wider than the 45 ACP ejector. I built a 45 ACP top end for my Delta Elite and I use the 45 ejector with both top ends. The result with the 10mm top end is a lager gap between the slide and ejector, but there is not possibility of the ejector hitting the primer and it still gets a full contact hit on the rim. I have not heard of the wider ejectors on the 1911 causing a problem with 10mm, I think you would have to rack the slide really fast to get enough of an impact to detonate the primer.