The specifications of the Remington ACR (Adaptive Combat Rifle) have finally been published. Bushmaster and Magpul are both still very much involved in the development of the rifle although I can see very little that has changed since the original Magpul Masada was unveiled.
The ACR is made up of an aluminum upper receiver and lower polymer receiver.
The lower receiver resembles the AR-15 and SCAR lower receivers. Like the polymer AR-15 lower receivers made by Calvary Arms, the ACR’s pistol grip is part of the mould and cannot be removed. The trigger group has a two stage trigger that has a pull weight of 6.25 lbs. The trigger group parts are compatible with the AR-15 / M16. Modes of operation are semi-automatic or fully automatic. All the controls are all ambidextrous.
The operating system was inspired by the AR-18. It uses a short stroke piston system – meaning the piston slams into the bolt carrier knocking is back and cycling the action. The AR-18 bolt carrier design has been improved, at least in my opinion, although it would be more costly to manufacture than the AR-18. The AR-18 has twin guide rods and twin recoil springs, see the photo below. The ACR has a recoil spring that inserts into the bolt carrier and is guided by steel rails that are attached to the receiver.
The bolt is in the AR-15 style with 8 lugs, one of which is an extractor. The bolt can be easily swapped out and a 6.8 mm SPC or 6.5mm Grendel bolt swapped in.
AR-180 (semi-auto version of the AR-18). Photo from carteach0′s blog.
ACR bolt carrier.
The rate of fire is 650-700 RPM. This is slightly higher than the SCAR which features a larger/heavier bolt carrier.
The side mounted charging handle does not reciprocate, unlike the SCAR, but can engage the bolt carrier and used as a forward assist.
Barrels offered will 10.5”, 14.5”, 16.5” and 18” in length and can be changed by the operator without tools. Magpul originally touted compatibility with standard M16 barrels, although Remington does not mention this on their website.
Two stocks will be offered: a foldable / adjustable stock and a fixed stock.
The 14.5″ carbine version of the ACR weights 7 lbs (unloaded)
Drake from Magpul posted these photos online: