I have sold few firearms that I own, but I only regret selling one, a Bushmaster M17s bullpup rifle. As such, Military Arms Channel decided it best to hit me where it hurts and highlight his own rifle (just kidding, I don’t think MAC would do that to me).
The rifle has an interesting history that involves some interesting characters like Charles St. George of modern .50 BMG bullpup fame (which many would recognize as being externally similar to the 5.56 rifle cousin. Ultimately the result of the Australian army’s search for a new rifle where the ended up with the AUG, the weapon hopped through a few companies before ultimately ending up with Bushmaster in the United States.
Internally, the weapon is very similar to the AR-180, using a AR-style rotating bolt. It is further a short-stroke gas piston operation, driving the bolt carrier back on two rails with two recoil springs, one on each rail. It uses a few AR parts like the magazine catch, but is predominantly a proprietary platform.
The Bushmaster M17s is not made anymore, but fortunately they are still available on the used market. Recently, K&M arms has been making a revival of the platform with their modernized version of the weapon the M17S556 and the big-bore cousin the M17S308. For those who love the original, K&M arms will machine various patterns and even has a new lower receiver with a vastly improved trigger compatible with the old extrusions.