Re: Reloading for Gas Guns?
I'm sure the's some stuff that will appear here that will get you started. There's already some good advice on the thread. The LC cases are very good for ARs, as is the advice for the CCI #41 primers. They're made specifically for autoloading guns with floating firing pins, like the ARs. Highknob mentioned the Varget with 75 grain bullets, and that's a top choice for heavy bullets (anything over 69 grains). That or RL-15 are probably the two top choices for competitive shooters using these rifles.
Beyond that, I strongly recommend the use of chamber gages to set up your dies, and remember that these rifles ALWAYS REQUIRE full length sizing. No excepetions, no exemptions, unless you just really want to have some problems. You might check over on 6mmBR.com or usrifleteams.com for more along these lines. Asa Yam pinned a chapter from a previous edition of the Sierra manual on reloading for gas guns that may be informative for you. There's several other good books specifically relating to the ARs, and several of them have some very good info on reloading for them. John Feamster's Black Magic, Derrick Martin's The Accurate AR, or Glen Zediker's Handloading fro Competition are all really good sources for this info.
And of course, you're always free to ask questions here. Always glad to help.