Barrett M468

This ain't yo momma's typical AR-15 variant... While it may use a direct impingement gas system, similar to the more standard M16/M4, it chambers the more niche 6.8mm cartridge. Barrett made a more updated version of this rifle and named it the "REC7", which instead uses a gas piston system.

Model taken from Tom Clancy's Splinter Cell: Conviction. Compatible with Sierra112's animated weapons pack.