Tanners in pa has a couple available for 1199$. About 600$ plus cheaper than ive seen them before.

Whats the difference between the 20 and 40?

DI (6920) vs piston (6940).

I just picked up Ruger 556E piston AR from Tanners for $799. They probably still have a couple left.

6920 has either magpul buttstock and hand guard or the old fashioned handguard and other collapsible butt stock.it is di only. 6940 comes in either di or piston. The upper is one solid piece. With picattiny rail all the way around.

Whats the difference between the 20 and 40?

The 20 is better

Why is the 6920 better.

Just busting chops really. I prefer the 6920 because an integrated quad rail you can never change is unappealing to me. For others it may be a big selling point.