Ciener makes a pretty good conversion kit for a number of makes and models. I picked up one for my Beretta 92fs and have been really enjoying the cheaper plinking it allows. I did have to do a little adjusting of one part before it would work properly but it was no big deal. As for ease of switching back and forth between the converter and the stock barrel, it's a snap. Just slip off the 22 slide/barrel and slip on the 9mm. Suprisingly accurate as well. I consider it to be a good purchase and fun to shoot.