AR10 and AR15! Isn't the break in designation at 223 verses 6.8 and larger? If you get a AR get one with removable carry handle or flattop.The AR is like a sportbike,there is all kind of modifacations you can do to them and parts that interchange.My next mod will be the trigger,I can live with the stocker but a 2 stage will be nice.Ammo is getting thin but Wally world near me has Remington green box for 6 sumthin a box,the UMC stuff is fine if you can get it priced right.Some AR makers will have a problem with warranty if you shoot Wolf or reload,reman.ammo.Checkout CMMGinc and you can spec a rifle out with price online,mine was 1200 with shipping,then I started with mods,a good flattop scope mount can cost you but can add options...I love my Larue qd mount.