I've never done a conversion on a non-ramped Colt 10mm but have on Kimber, SIG and PARA so don't see what the difference would be doing any other brand of 1911.

The Kimber Stainless Target II will run:
.38 Super
9x23 Winchester
9mm Largo
9x19
.357 SIG
.40 S&W
10mm
...all on one slide.

Lucked into a Kimber parts kit in .45 with every part but the frame...so added .45 ACP and .45 Super to the mix. An then found of of the .22 Conversion Units in silver...

Added flat bottom firing pin stops and extra power firing pin springs to the slides. The mainspring was increased to 25#. The recoil springs are matched to the caliber. 14# for 9mm. 18.0 for most of the rest and 20-24 for 9x23, .10mm and .45 Super...

Early pictures before everything was all together:

Kimber Stainless Target II System... - 24hourcampfire

Four-Caliber STII... | 1911Forum


If trying to go from 9mm to 10mm it will all depend on the brand...Colt will not, RIA will not, Kimber will... haven't had time to experiment with others.


When I ordered the 6" .38 Super barrels from Fusion to fit on the Kimber and PARA longslides, Bob the owner, said it wouldn't work...I told him about the Kimber I already had and said it would work fine... He shipped the barrels and my local 1911 smith fitted them and they run 100% and VERY accurate...

Bob