The redheaded stepchild of the SCAR contract was Robinson Arms’ XCR, an interesting design from a small company in Salt Lake City, UT. A rifle that is part AR-15, part FNC, and part noodle, the XCR represents an attractive looking and interesting might-have been, and now exists as a small player in a big market (although, as Ed knows, it’s big in Canada!).
Still, Robinson Arms has stuck by the XCR, and continues to improve it. The XCR-M, the 5.56’s bigger brother, recently underwent an update where the tappet gas pistol of the previous M variants was replaced by the XCR’s more characteristic AK-style direct gas impingement operating rod. The primary advantage of this is that the entire piston and operating rod withdraws from the rear of the rifle, allowing the forend to extend past the gas block without impeding disassembly. Besides greatly improving the look of the rifle, this also better facilitates currently fashionable grip techniques, and gives more forward real estate for attachments.
The XCR is, broadly speaking, a sound design that is light, strong, and reliable, at least in theory (my experience with these rifles is nil, so I am speaking from their design characteristics only). One thing the XCR brings to the table that I have discussed before is a shelf in the bolt carrier, which prevents the bolt from trying to complete its turning move before it can lock, which reduces friction and greatly eases feeding:
Robinson Armament offers the XCR in a wide variety of calibers. The XCR-L is offered in 5.56mm, .300 Blackout, 6.8mm SPC, 7.62x39mm, and 5.45x39mm. The XCR-M is offered in .308 Winchester, .243 Winchester, and .260 Remington.