Hello to all of you, my name is Mike I am new to Ar's and to this forum. I went out with my friend whom has a Bushmaster 16" carbine(A2?) and we put about 300 rounds thru it the other day. That's all it took for me, I'm hooked. A few weeks later, I had the opportunity to trade a guy I know for a Colt 20" h-bar comp match. I like the gun ALOT, but now I am thinking about selling some of my handguns that I don't shoot that much anymore so I can buy(build) another one heh. I was just wandering where I might find a list of what all the number designations mean, I.E. A2,A4,M4 etc. I think what I want is an M4. Do they make those in the h-bar? Also my rifle has a solid one piece FF aluminum handguard on it. It there any cooling benefits to this over one of those RAS FF units? I really like the tech looking stuff and want to build another rifle from the ground up utilizing some of the rail system stuff. Also, on my rifle there is a scratch in the finish on the forward assist(?) and I was wandering if there is any tricks to getting rid of it without compromising the value or mechanics of the gun. Anyways, that's about half of the questions I have for now but I don't want anyone to have to write a novel answering them. Thanks for all your help and I'm really excited to be on the forum and to be owning an AR.