ARES M110 upper receiver
 

I have the chance to put my hand on a spare Ares M110 upper, and I want to build a M110 carbine with 14/16 inch barrel + URX 3 or something similar.

But do ARES Upper receiver (and the M110 one ) fits standard barrel nut, or copy URX barrel nut?

I know ARES really likes to use proprietary parts in everything,

Fits standard nut.
Fake gaz tube is oversized.

I have a 20" SPR barrel with a 13" URX4 on it. If does not use the same type of nut than the stock ARES URX rail kit.