I was wondering how these worked. I have a Colt MK4 Series 70 National Match Target that has very expensive tastes and I was thinking I could use it a lot more if I had a conversion kit for it. I don't want to have to permanently modify the gun, though, or do anything that might damage it. Any opinions? Thanks.

I use a post-war Colt Service Model Ace conversion on a Gold Cup National Match and have no problems other than the expense of the Ace mags.  Fortunately I now have 5 of them and don't foresee having to ever buy anymore.  
However, I've haven't had any experience with either the Ceiner or the Wilson conversions.

I take it you do not reload? The cost of the real Colt conversion will buy you another complete, quality .22 pistol. I had two of those years ago, with the "floating chamber" and it worked OK. The Ciener unit supposedly requires no modifications and the gun can be put back to original configuration. Last prices I recall on Cieners were a bit over $200, with one magazine. Never owned a Ceiner conversion, so thats all I can tell ya. I never noticed any used ones at gunshows, so I assume they may work?

You are correct. I do not reload. I would love to get a 22 target pistol, but in my state (MA), they have clamped down on handguns so much that the only new one I can buy is a S&W, and the only real target pistol they sell is the Model 41 which is retailing for around $750.00!

My only hope is to find a used one, but they are few and far between. I am still hoping to maybe find a Ruger MK 2. Anyway, if I can't, the Ciener conversion at around $200.00 becomes a good alternative. I do have the 45 which I can't afford to fire too much, so this would give it some use. With the price of match ammo, which is what it likes best, the conversion kit is not so bad.

I know I should reload, and I will get to it eventually, it is just something I will approach with caution, and I'll do it when my living situation is a little more relaxed.

Thanks for the comments and opinions. Much obliged.

I have and occasionaly use a Kimber 22 conversion.  I got it as part of a deal and I've been very impressed with it.

It makes for a great change of pace from shooting full house 44s.

I highly recommend them and it's even better if you can find a 1911 frame to dedicate to it.

http://album.gunsnet.net/data/philinseattle/159_p978.jpg

http://album.gunsnet.net/data/philinseattle/159_p979.jpg

I also have a Kimber 22 conversion for my Kimber 1911. You take off the slide and install the 22 slide, install the mag and thats it! It shoots really good, good enough for informal target shooting. I like it alot, shoot it alot!