This will function perfectly in both pistols and short-barreled rifles. Pistol - AR pistol length systems can be used in super short barrels. This will lead to increased wear and tear on the rifle, and wear it out faster than a matching gas system. Sounds great, however, it will start to beat the gun. An over-gassed rifle will be throwing that bolt carrier group rearwards hard, fast and hot. The rifle’s ability to cycle will be impaired.Īlternatively, if you have a barrel that is too long and a gas system that is too short you’ll run into over gassing. This can cause a variety of issues including failure to eject and extract. If the gas system is too long and the barrel is too short the gun will likely run sluggishly. If it doesn’t you’ll run into two distinct issues.

This only affects reliability in extreme cases.Ī gas system must match the barrel length of a rifle due to dwell time. Heavier, slower rounds have a longer dwell time. Your choice of ammunition can also create differences in dwell. As you’d imagine the longer the barrel the longer the dwell time. Dwell time differs between AR rifles due to barrel length. This is due to how long the projectile stays in the barrel. The big question is why? A universal system would make more sense, but unfortunately, that simply doesn’t work.

The gas tube length should increase as the barrel length increases. If you can’t tell, the length of a gas tube changes as the barrel length changes. There are 4 different lengths for a gas system. The buffer and buffer spring send it forward to complete the rifle’s operation. The bolt carrier group retracts and extracts and ejects the round. The gas strikes the gas key on the bolt carrier group and cycles the rifle. This port connects to a gas tube that feeds the gas into the receiver. This means some of the gas created by the round fired exits the barrel into a port on the 12 O’clock position on the barrel. We will help you can choose the perfect length gas system for you. So for the latter group, we are going to dive deep into the different gas system lengths used in AR 15s. Some folks already know there are many gas systems sizes, and some reading these are just now finding out. More specifically, different length gas systems. One of the more complicated systems in the AR 15 is the gas system. The AR 15 rifle isn’t a complicated rifle and most people can build one by themselves with little to no training.

Sks how to take the gas system off