With a nod to @phishi and to keep from sidetracking other AR threads, I'm posting this chart, shamelessly taken from a post by @melbo (with a big thanks for posting it in the first place.) EDITED - to list the following relevant threads here, which got me thinking about this: Not all AR15s are created equal. | Survival Monkey Forums Monkey configuration AR15 | Survival Monkey Forums It's a good chart, using Colt as the standard, for good reason. The question is, what would you monkeys add to the chart? Is there anything worth considering that isn't on there?