Can I convert 10mm 1911 Colt to 45ACP ?

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Al Robbins

Sep 14, 2006
Endless Mountains PA.
I have 2 beautiful Colt 10mm's - a Delta Elite and a Delta Gold Cup. I have a Ceiner 22LR conversion that works for both of them - and works very well. I carry a Kahr P45 (45 ACP) as my every-day concealed carry gun and I'd like to buy a slide assembly and barrel in 45 ACP so I could shoot that caliber in the Colt 1911 (10mm's). Then, if that worked, I'd have 22LR, 10mm and 45 ACP on one platform.

Does anyone see any reason this can't be done? I already know the 45ACP Colt magazines fit the 10mm Colt guns. But will they work reliably? How about ejection - will that be OK?

I can buy a complete 45 ACP "upper" for less than $300 and I'd like to know the feasability of doing this before I spend the money. BTW I have experience as a mechanical engineer and some experience as a gunsmith, but wouldn't want to mechanically modify the 10mm's

Thanks for your help.
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Breech face and exttractor

I am talking about a complete slide assy in 45 ACP which would include a 45 ACP breech face and extractor. I do question ejector placement, wonder if its different or critical. Thanks.
Yes, you can convert. Send me the Delta and I'll send you a .45 ACP Kimber.;)

All kidding aside, I have never tried it. Hopefully someone here can help you out.
If one can convert a standard 1911/.45 to .38 Super or 9mm or 10mm or .22LR etc. by changing uppers and using appropriate magazines, why shouldn't it work the other way?

OK, .45-to-10mm conversions aren't generally recommended because of frame strength...10-to-.45 would be a non-issue.

A 1911/22LR may have a frame nonconducive to anything else...which would be foolish of the manufacturer. Having to order special runs of weaker frames vs. having ONE frame fit all (cost); keeping them separated in the factory vs. a "weak" frame slipping through in the wrong chambering (insurance/reputation); excess inventory of "weak" frames collecting dust vs. being out-of-stock so customer orders .22 conversion kit instead (demand), etc.
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