Thread: suppressor pressure

Originally Posted by sneeze

Yes it will increase the pressure in the gas system but after the bullet has passed the gas block. As in @Puffins post, to give the symptoms described it would need to increase peak chamber pressure ( where the bullet will be only 3-4 inches down the barrel) to give the symptoms described and I dont see anyway that can happen by simply adding a suppressor. I would looking else where. What projectile are you using, what velocity and what chronograph?

Iv also see no significant gain in velocity with suppressors using reliable chronographs and significant sample size.

I would agree that there is no significant gain in velocity but tests here in NZ have shown that good suppressors have increased velocity by a few fps in .22 rimfire rifles.

Yes, gas pressure is increased after the bullet passes the gas port, but pressure is then equal throughout the barrel. The increased pressure after the bullet passes the gas port means that the cartridge is still gripping the chamber wall when the action starts to open. In extreme cases the extractor will rip through the rim of the case. I have cured many of these problems over the years by making an adjustable gas port that can be tuned to suit each rifle, and in many cases it has also been necessary to bore out the suppressor by up to 1 millimeter to give a faster pressure drop. The bigger the cartridge, the worse the problem. Smaller rounds like the .223 have much less gas volume and lose the pressure quicker, although the higher residual pressure in the bore manifests itself by coating the cases in powder residue. An adjustable gas port addresses this situation fairly easily. The sticking case problem is more common with the .308 or bigger cartridges. I have been sorting these problems for other gunsmiths (who don't want to know about them) for many years, and still get to do them even though I am retired.