After trying a few different .22 pistols for the twins, including the Mark IV and the 22/45, I settled on the Browning Buck Mark Field Target. If you want something that would be a good transition piece to a 1911 while still being a really nice little comp pistol that he could make really good scores with then that is a really good .22. Now there are some really good .22 conversion kits for 1911's out there. I didn't go with that because the twins just aren't big enough yet for a full size 1911 for really good accuracy but your son my be bigger than them. Don't know his age. Take a look at the whole buck mark line as there are quite a few in it. They cost a bit more than the Ruger's but they are well made and shoot like a dream.