View Full Version : Mag-na-Porting/ Porting in general

Futo Inu
August 6, 1999, 11:37 AM
This is a question for some of you engineering-knowledgeable types.

I recently had a pistol barrel mag-na-ported which is nothing more than two trapezoidal-shaped holes "cut" into the barrel at about the 10 oclock and 2 o'clock positions. However, most advanced porting systems/comps/muzzle brakes, IINM, will be cut at an ANGLE from rearward on the outside to forward as it goes to the inside (rather than perpendicular to the barrel), so that the gas is ejected up and BACK to push the gun down and forward to reduce muzzle flip and felt recoil respectively. So, wouldn't these Mag-na-port straight/un-angled cuts be inferior or lacking with respect to the latter (felt recoil) and do nothing more than reduce muzzle flip only, which in turn it seems to me would actually INCREASE felt recoil, since the pistol is kept from "releasing" the recoil upwards by way of the muzzle flip, so must instead direct it backwards only - into your hands (which BTW should nevertheless be effective in target re-acq. because of reduced muzzle flip, but the recoil would still be there, seems to me).

I suppose the reason why these are not cut at an angle is because there is not enough distance comprised of the barrel's outer edge width to make a long enough "channel" to direct the gas in a rearward direction; in other words, without a thicker "compensator" unit, it doesn't matter whether the cuts are straight or angled, the gas does not travel far enough through a channel to divert it in a rearward direction. My question appears to be clear as mud by now, so I'll quit while I'm behind to see if anyone knows what I'm asking. TIA.

[This message has been edited by Futo Inu (edited August 06, 1999).]

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.