To date, my SR1911 will accept the following:
Marvel...sub 2" gps at 25 yds sitting
Ciener...Same as above
Advantage Arms Inc. (.22 Conversion Kit Model 1911-22T)...Same as above
Colt .22 LR Conversion Unit ... would not fit.
Hope that helps...Rodfac
PS: the Ciener unit works as well as any of the above, shoots to point of aim with fixed sights and is the best value for the money. The "Commander" length (4-1/4" barrel length) will fit, function, and is accurate as hell on all of my Colts, a Remington Rand of WWll vintage, and the Ruger SR1911 offering!!! If you're looking for a shorter, more "packable" .22, the Ciener is the way to go. Rod
Add'l info posted elsewhere on the net:
I've been experimenting with some .22 Lr Uppers on my SR1911. Of the four I have access to, the Advantage Arms, Marvel, and Ciener units work well with groups averaging down around 2" at 25 yds, with Remington, bulk, .22 LR HPs of the Golden Bullet variety. I was unable to get the Colt Conversion to fit on the frame. Here are a some pics of the Ciener, Marvel, and Advantage Arms units. Best Regards, Rodfac
This is Ciener's Conversion Unit, in the "Commander" length; good functioning and it shot to the non-adjustable sights!
This is Marvel's Conversion, the 5" full size model with the first target I shot with it...range 10 yds, Weaver Stance.
Advantage Arms 22 Conversion...accuracy comparable to the other two, elegant, but pricey. It locks open after last round, the other two do not. The breech block assembly on the Advantage reminds me of a S&W M-41. Also of note: the slide stop is a two part piece...unlike any other 1911 part I have seen. In use, you position the side piece, to depress the locking pin, then insert the cross frame post! The slide notch for the slide stop is hardened steel, the remainder of the slide is aluminum.