In this video, I show the effects of different action springs and buffers on the three phases of AR-15 recoil, using a BCM 20″ upper for demonstration purposes.
I’ve copied the text from the video here so that you don’t have to wait 60 seconds while it scrolls by on the screen if you don’t want to.
There are three distinct phases of rifle movement immediately after an AR-15 is fired.
The first phase is what most people think of when asked to describe “recoil”. The projectile exits the muzzle, and the weapon pushes back against the shoulder of the shooter. Depending on the choice of muzzle device, the muzzle may rise, drop, or stay on target during this phase.
The second phase is when the bolt carrier group reaches its rearmost point of travel. This generally causes the weapon to push back against the shoulder of the shooter, and the muzzle to rise, regardless of muzzle device. Depending on the gas system, buffer, action spring, and other factors, this may be reduced or eliminated.
The third phase is when the bolt carrier group travels forward and stops after hitting the barrel extension. This generally causes the weapon to come forward, away from the shoulder of the shooter, and the muzzle to drop slightly. Depending on the gas system, buffer, action spring, and other factors, this may be reduced or eliminated.
In this video, the first phase is very similar throughout. An A2 muzzle device was used for all videos.
Pay attention to the movement speed and direction of the rifle during phases 2 and 3 in each of the following clips. It may help to focus on one point throughout the video – the rear sight, for example, or the muzzle device.
From the shooter’s perspective, the most desirable recoil characteristics were achieved with the carbine buffer and the Wolff reduced power spring.
Offering almost exactly the same amount of “shootability” – at least during phase 2, with slight forward movement during phase 3 – was the H2 buffer with the Tubb CS flat wire spring.
The H2 buffer offered good recoil characteristics with all springs, while the carbine buffer was excellent with the reduced power spring, as mentioned, but not nearly as good with BCM and Wolff extra power springs. It also did quite well with the Tubb CS flat wire spring.
From a reliability perspective, the H2 buffer is more desirable than the carbine buffer (although no malfunctions were experienced with any of the spring/buffer combinations). The carbine buffer/reduced power spring combination would only be desirable for competition or target shooting – but it would excel in those roles.
Do not assume that the characteristics shown here would also apply to midlength and carbine gas uppers. Even other 20″ rifle gas AR-15s would not perform in the exact same manner with the same components. Future videos will cover the carbine and midlength gas systems and how these components affect their performance.