Similar modifications sometimes suffer from reliability problems due to the close proximity of the gas port to the muzzle, which throws the timing of the weapons gas system off and makes it more sensitive to gas port diameter and port pressure variables introduced by the ammunition.īushmasters solution was to use a low-profile gas block in the normal position for carbine-length barrels and fit the front sight towergas block, which is not connected to the gas system, further forward to create the longer sight radius. Some models also remove the forward assist and the dust cover, and use a thinner barrel design to save additional weight. It saves weight by using polymer instead of the traditional steel or aluminum in the upper and lower receivers. The First Generation rifles were chambered for the 5.56mm round.īushmaster First Generation rifles are very rare and are collectables.Īccording to the company in 2010, Bushmaster began making the ACR available to the civilian market, posting it on its website. Originally marketed for police and the military, Bushmaster later changed its unique hybrid version AR-15M-16 to the standard ColtArmalite design.

This first generation model used the AK-47 gas system and the recoil spring is located within the upper barrel gas system as compared to the AR-15M-16, where the recoil spring is located within the butt stock.

Stainless steel or chrome molybdenum barrels are available on certain models.īushmaster Firearms originally produced their First Generation rifle using an aluminum lower receiver paired to a stamped steel upper receiver. Some barrels are available with 1:7 rifling, on special order. Most Bushmaster barrels are 4150 steel, offered in 1:9 twist rate, and chrome-lined to increase durability. It also announced that as a result, Bushmaster, TAPCO, DPMS, and StormLake Barrels would no longer be produced. Those who chose to give up their shares would get paid off by an unidentified lender. According to the company: It is apparent that the Sandy Hook tragedy was a watershed event that has raised the national debate on gun control to an unprecedented level.

Bushmaster serial number list bk