well I picked up a new weapon at the 1500 this weekend. I bought a s&w m&p 15-22 this weekend and fell in love with the ar prior to this i was strongly opposed as having a bad experience with a buddies junk ar-15 and never looked into them. I broke down and bought the smith as a fun cheap gun to shoot and to teach my brother proper gun safety as he is only 8 and it is time for him to learn. anywho to the questions i am looking to get a larger caliber or a couple of different uppers and one lower for it. what are the good names? are there good kits? what is what in the world of ar's i am new to them so sorry for getting anything wrong. also i got it from midwest gun exchange and they were very polite and I personally recomend their services to anyone they gave me a good deal on the weapon itself. thanks for any help and recomendations for steering me in the right direction.