I've been looking at AR billet 80% lowers to build into my dream gun. Trying to decide between an AR-10 or AR-15. Information on advantages and disadvantages between the two platforms would be helpful. Things I know about are the price difference, availability and calibers. Also, would like to know brands to avoid do to poor quality and/or customer service.

Thanks

I would just buy a lower if it was my first one.

Two different worlds there buddy. The AR-10 and AR-15 are two different animals...

What is this rifle's purpose? SHTF? Training? Hunting? Target?

Target and hunting. Looking for medium distance 200-250 yards. and up to Elk sized game.

I have help from a machinist to walk me thru the machining aspects of the build.

IMHO, I'd go AR-10. .308 Win packs one heck of a punch.

Handled a DPMS .308 today; nice rifle.
Concur with the previous poster; I wouldn't try to build a lower for my first one, regardless of how much help you have.
Moon

BOTH!

Nah, but if you are wanting to hunt bigger game I'd go with a .308 instead of 5.56. Also, depending on which state you are in, you may not even be able to hunt larger game with a 5.56 AR-15.

Plus, its usually easier to track an animal that you shot with .308 than with 5.56.

Just my thoughts on it. Good luck.

Also, like others have said, I'd just buy the lower rather than machining it yourself unless you have a really important reason for doing that. A lot of work, easy to mess up, and you'll probably get better quality if you buy a manufacturer's premade lower.