I have long been taught that:
1. a properly-sized recoil spring will prevent a recoiling bolt from striking the back of the receiver;
2. if you want to use ammunition with a higher recoil impulse, you should also change the recoil spring to match that new ammo; and
3. as a recoil spring wears, you should replace it before it allows the bolt to strike the receiver.
In the real world, people may change ammo without realizing that it has a different recoil impulse. They also may not monitor their recoil spring wear closely enough to catch it before their bolt starts to contact the back of the receiver. Thus, there may be a role for a fallback buffer that normally does nothing, but is there in case it is needed.
I think that such a fallback buffer should be thin so it does not excessively shorten the distance available for the bolt to travel. It should also have an OD the same size as the OD of the bolt so it has the best chance of diffusing any impact energy. It should be oil resistant so it holds up inside the firearm. Finally, it should be hard enough so the recoil spring does not cut or tear the buffer.
The closest thing I can find commercially available are 1/2" rubber sealing washers, but they fall short in several respects. First, they have a 1-1/16” OD, which is smaller than the OD of the bolt. Those washers are available in either neoprene or Buna-N. The Buna-N is oil resistant, but the neoprene is not. Further, based on my early experiments, both the neoprene and Buna-N washers are too soft to avoid being cut or torn by the recoil spring, even though the bolt never touched them.
For my next experiment, I plan to try a buffer made from UHMW (ultra high molecular weight polyethylene). UHMW shows to be oil resistant, impact resistant, and harder than either neoprene or Buna-N. This experimental buffer will be 0.10” thick, with an ID of 0.500”, and an OD of 1.125”.
Before I get too far along reinventing the wheel, has anyone else already tried something similar? If so, what were the results? Any other thoughts or guidance to share?
Thanks,
Jim
1. a properly-sized recoil spring will prevent a recoiling bolt from striking the back of the receiver;
2. if you want to use ammunition with a higher recoil impulse, you should also change the recoil spring to match that new ammo; and
3. as a recoil spring wears, you should replace it before it allows the bolt to strike the receiver.
In the real world, people may change ammo without realizing that it has a different recoil impulse. They also may not monitor their recoil spring wear closely enough to catch it before their bolt starts to contact the back of the receiver. Thus, there may be a role for a fallback buffer that normally does nothing, but is there in case it is needed.
I think that such a fallback buffer should be thin so it does not excessively shorten the distance available for the bolt to travel. It should also have an OD the same size as the OD of the bolt so it has the best chance of diffusing any impact energy. It should be oil resistant so it holds up inside the firearm. Finally, it should be hard enough so the recoil spring does not cut or tear the buffer.
The closest thing I can find commercially available are 1/2" rubber sealing washers, but they fall short in several respects. First, they have a 1-1/16” OD, which is smaller than the OD of the bolt. Those washers are available in either neoprene or Buna-N. The Buna-N is oil resistant, but the neoprene is not. Further, based on my early experiments, both the neoprene and Buna-N washers are too soft to avoid being cut or torn by the recoil spring, even though the bolt never touched them.
For my next experiment, I plan to try a buffer made from UHMW (ultra high molecular weight polyethylene). UHMW shows to be oil resistant, impact resistant, and harder than either neoprene or Buna-N. This experimental buffer will be 0.10” thick, with an ID of 0.500”, and an OD of 1.125”.
Before I get too far along reinventing the wheel, has anyone else already tried something similar? If so, what were the results? Any other thoughts or guidance to share?
Thanks,
Jim
