Crown City Arms/Kart Sporting Arms mod. Hummingbird cal. 22 lr.

I have a chance to buy this pistol : Crown City Arms/Kart Sporting Arms mod. Hummingbird cal. 22 lr. any news or experiances about this?

Not sure about lower, but the Kart upper is exceptional!  Cant imagine the combo being bad with both married by the factory.

All I can remember about the old Kart .22 conversions was that they were exceptionally accurate, but lacked reliability. I would pass if you are considering using it for serious competition.

Way back in the 70s, Crown City arms made lowers (frames).  They were investment cast, I believe, and were generally considered “OK”.   They were based on the WW2 dimensions as I recall, so almost any GI slide and barrel (plus all the rest of the parts), would drop in and make a functional gun.  A lot of them were used in IPSC builds.  Not many were built as 45 bullseye guns as the smiths of the day wanted Colt.

+1 on Wobbley's comment.  They were investment cast, kinda "soft" compared to forged.  I did a build from parts back in the last 70's / early 80's.  It was a functional gun, but there are better frames, especially today.

On the other hand, for a Kart conversion, which does not require any really tight slide to frame fitting (actually none), it would be acceptable, if the hammer / sear pin holes are properly placed so as to not require a tremendous amount work when setting up a trigger.

The main questions are: 

Does it have actual Kart magazines?  

What is the serial number? (Will give an indication on when the Kart unit was produced and therefore the source of the slide used for modification or build - its on the top of the slide and visible when locked back.)

Does it have the original Marlin MicroGroove barrel used in most Kart units.  (You can tell if the barrel has many small lands, rather than 2, 3, or 4 lands.)

If you can disassemble, look at the bottom of the conversion unit that sits on the frame above the cut out for the standard lower barrel lug / link.  If the pads look like they've been heavily filed, then the unit might have been fitted too loosely on the frame or another frame in the past. This may or may not be an issue depending on how the unit feels when the locking rod is screwed in tightly when mounting the unit.  

Also, if you see gold colored brazing around the edges of the feed ramp / bottom spacer at the bottom of the breech / chamber end, that is normal. 

Be sure to check the recoil springs - many are cut too short in an attempt to alleviate feed / function issues. A lot of feed / function issues are the result of the magazine catch not holding the mag firmly and allowing it to move back a forth. A common issue when using Ace magazines. 

CR

PS / Yes, I have multiple Karts, both 5 and 6 inch versions; open sights and optic shrouds for both lengths.  Even have a couple of very early production magazines with the pinned aluminum floorplates. I probably need to go into ".22 Conversion" Rehab.

Crown City Arms in the 70s maybe early 80s bought Kart conversion units and put them on their frames and called them the Hummingbird, they had several versions of 1911s and they all had the name of birds. Somewhere I may still have their catalog that supports what I just said. 
Tom Ginovsky

Thank you to all for the useful information!

BE Mike wrote " I would pass if you are considering using it for serious competition"


I have not found this to be the case, my Kart has been extremely reliable.
Phil

I shot at least somewhat seriously with mine and the reliability so far has been on par with Pardinis, Hammerlis, AW93's, etc., on the line.

The thing is, just like Marvels / Nelsons, etc., people start messing with lighter / cutting recoil springs and light mainsprings and trying for 2 pound triggers when they should be shooting the darn things at +/- 3 to 3.5 pounds to get ready for CF / .45.  (In my personal opinion). 

Of course the main issue is finding un-molested Kart magazines.  People screw up the feed lips and open up the magazine catch slot in a effort to correct issues that come from somewhere else.  

CR

Todate I've had no issues using Colt magazines with my Kart or marvel for that matter

I also have some Colt mags that work just fine
Phil

I have found the Jagemann magazine to be reliable in my Karts. I have Kart, Colt Ace and prefer the Jagemann.