Im looking into getting my first AR and have a few questions. Im going to be boar hunting with it so I was thinking of getting an AR10 in 7.62x51mm. However I was also wanting to get the M16a4 look going with it. So would I be able to get a KAC RAS M5 rail for that gun? or would the barrel be too big?

Also from what I read on here you cant put a 7.62x51 upper on a AR15 lower but I saw an add from colt saying that their AR10 lower could accept a 5.56 upper. Is this common to all AR10 lowers? Ill see if I can find it again.

Is it any more difficult to care for an AR10 vs an AR15? What about the recoil? Im not really an experienced shooter so would it be more difficult to learn with the recoil from the 7.62?

Last thing is manufacturers. I dont want to skimp out and get cheap parts and run into problems down the road. So what are some quality manufactures I could go with? I was thinking bravo company if I were to get an AR15 but how are their AR10 parts? Ive also seen pictures of some rifles where the lower doesnt really match the upper. The upper would be flat black while the lower would be glossy. Is this common? Would they eventually match with wear or what can I do to avoid it if Im ordering the parts online?

Get a standard 5.56 lower and get a nice 6.5 Grendel upper.  All your days will be filled with sunshine after that!

Ok lots of questions....

1.  Read the ammo FAQ...You can use 6.8, 6.5, 7.62x39 and many others on an AR15 lower...All should be good for boar as well as plain old 5.56 w/ good ammo.

2.  Fit and finish vary by manufacturer...You can even get an upper and lower from the same company and they wont match perfectly...BCM is gtg but they don't make AR-10 rifles...If you still want to go that route then take a look at Larue.  Very nice and accurate rifles and they actually just came out with a hunting rig at Shot Show that should be released sometime soon.

I would go with a 16" mid-length stainless from BCM w/ a nice variable scope...