I have never converted an AR-15 however I am looking at getting rid of my .308 and was looking at converting my AR to be able to shoot .308 and .223. How hard is it to convert an AR and dose anyone have any experience with a .308 AR? Are they worth the work, price, etc? Thanks everyone.
.308 AR's use a different lower with a larger magwell to accept the larger magazines. You might want to look into .300 Blackout, which uses standard AR15 mags, lowers, and even bolts. Only thing that needs changed is the barrel.
ETA: if you decide to buy a .308 pattern AR, be advised that they are NOT as standardized as the AR15 pattern style of rifles. Things may not be interchangeable between manufacturers.