Hi! I'm new to ARs - I'd like to purchase a .22lr AR, and I was thinking it would be great and cost effective if I could buy a complete .22lr AR that I could later convert to .223/5.56, either with a new upper, or (even better) by replacing the BCG and magazines. I shot a S&W M&P 15-22 yesterday and loved it, but I know these don't accept standard AR uppers. I would be using it as a .22 for cheap/fun plinking/range shooting, and to get my wife into shooting (she shoots my 9mm XD(m), but is a little intimidated by the recoil). My local range does not allow rifle calibers. I would use 5.56 for range shooting and 3gun. If I got the 5.56 and decided I loved it, I'd probably build a higher quality rifle in the future. My questions: Is there a complete rifle similar to the M&P 15-22 (hopefully in that price range) which I could later convert to .223/5.56 by replacing the BCG/magazine, similar to how you would convert a .223/5.56 to fire .22lr? Is there a complete rifle similar to the M&P 15-22 (hopefully in that price range) that I could later convert to a .223/5.56 by replacing the upper/magazine? Is this whole idea dumb? Would I be better off buying the .22 AR now, and a totally different .223/5.56 rifle later? If so, why? Please be patient if I asked a completely ridiculous question (I'm really new to ARs)! Thank you for your help!