The Firing Line Forums - View Single Post - Mag-na-Porting/ Porting in general

Daniel Watters · August 6, 1999, 07:37 PM

Let me summarize: you want to know why back-to-front slots would be more effective than side-to-side slots? One explaination that I've seen used the cylinder gap on a revolver as an example. While some propellent gas will bleed off at the cylinder gap, the majority continues straight into the barrel. Consequently, if side-to-side slots are narrow enough, gas won't be vented as well as a back-to-front slot.

Expansion chamber compensators work because the gases strike the front baffle instead of just by redirecting the propellent gases upwards. Mike Plaxco gives an example from cutting up compensators: one set has larger vertical ports cut, while another set has a larger bullet exit hole cut. As the top port is opened up, no real change is noted. However, as the bullet's exit hole is opened up, muzzle flip increases. Plaxco recommends that exansion chamber compsenators work better as the surface area of the front baffle is increased. I suspect that some of the angled baffle designs work 'better' simply because the angled baffle has more surface area than a vertical baffle of the same vertical height...simple trigonometry and geometery. Multiple chamber compensators add more baffles and thus another area for the remaining gases to work against.

August 6, 1999, 07:37 PM	#2
Daniel Watters Senior Member Join Date: February 7, 1999 Location: USA Posts: 644	Let me summarize: you want to know why back-to-front slots would be more effective than side-to-side slots? One explaination that I've seen used the cylinder gap on a revolver as an example. While some propellent gas will bleed off at the cylinder gap, the majority continues straight into the barrel. Consequently, if side-to-side slots are narrow enough, gas won't be vented as well as a back-to-front slot. Expansion chamber compensators work because the gases strike the front baffle instead of just by redirecting the propellent gases upwards. Mike Plaxco gives an example from cutting up compensators: one set has larger vertical ports cut, while another set has a larger bullet exit hole cut. As the top port is opened up, no real change is noted. However, as the bullet's exit hole is opened up, muzzle flip increases. Plaxco recommends that exansion chamber compsenators work better as the surface area of the front baffle is increased. I suspect that some of the angled baffle designs work 'better' simply because the angled baffle has more surface area than a vertical baffle of the same vertical height...simple trigonometry and geometery. Multiple chamber compensators add more baffles and thus another area for the remaining gases to work against.