I made fun of a friends compensated Sig P365

[lewmed]

 I made fun of my friends compensated P365 until I shot it. It's a standard 3.1" upper with a PMM Micro JTTC comp on a Wilson Combat XL lower. I shot two twelve round magazines through it one each of 115gr Gold Dot and 124gr Gold Dot +P.  I can't stop thinking about it I may have to build one. Shooting it feels like shooting a full size 380 acp pistol and it's the same size as a 365 XL.

[M1A4ME]

I was skeptical of the benefits.  I have an M&P 1.0 5" 9MM PC pistol.  Right off the bat, shooting it with the 115 grain hollow points, you can see/feel the reduction in muzzle rise.  It's real and very noticeable. 

My wife had a Shield 9MM PC with the ported barrel/slide and I really don't notice the difference between the ported Shield (3.1" barrel) and my Shield (standard Shield).  I just don't.

I recently bought/assembled a couple M&P 2.0 4" 9MM slides with ported barrels.  The barrel extends out past the slide about 1/4" or so and the ports are cut in the barrel.  I can't tell, shooting it, that the ports reduce muzzle climb.  I can see they vent gas as the end of the slide has powder residue on either side of the front of the slide.

I wonder, if the difference, is were the ports are.  Ports farther back in the barrel vent gas and a higher pressure vs. vent out near the end of the barrel.  The closer the bullet gets to the end of the barrel, the lower the pressure is.

I've got a couple/three AR15's (and an FAL) that the barrels were shortened on from 20" to 16 to 18".  All three of those were unreliable right after the barrel shortening.  The closer the ports are (gas port or gas vents) the lower the pressure is going to be at the vent/port because the bullet exits the barrel sooner so the gas pulse time is shorter/lower.  On the ARs/FAL I drilled the gas ports out to the next largest size and all three were reliable.

I have no plans to enlarge the holel on any of the pistol barrels 

Ports are ports.  Size, proximity to the muzzle, caliber/pressure at the port all make a difference.

[lewmed]

 I think what amazed me was after firing my stock 365 and  XL then firing my friends pistol with the little 3/4" long comp I could see such a huge difference in muzzle rise and recoil. I fired the same ammo in each pistol but the recoil impulse and muzzle rise was much less and the spent cases were tossed about 4 to 5 feet not the usual 6 to 8.  The slide still locked back on the empty magazine and it didn't feel sluggish at all. I don't know about EDC but it might make a cool range toy.

[ams]

I was skeptical of the benefits.  I have an M&P 1.0 5" 9MM PC pistol.  Right off the bat, shooting it with the 115 grain hollow points, you can see/feel the reduction in muzzle rise.  It's real and very noticeable. 

My wife had a Shield 9MM PC with the ported barrel/slide and I really don't notice the difference between the ported Shield (3.1" barrel) and my Shield (standard Shield).  I just don't.

I recently bought/assembled a couple M&P 2.0 4" 9MM slides with ported barrels.  The barrel extends out past the slide about 1/4" or so and the ports are cut in the barrel.  I can't tell, shooting it, that the ports reduce muzzle climb.  I can see they vent gas as the end of the slide has powder residue on either side of the front of the slide.

I wonder, if the difference, is were the ports are.  Ports farther back in the barrel vent gas and a higher pressure vs. vent out near the end of the barrel.  The closer the bullet gets to the end of the barrel, the lower the pressure is.

I've got a couple/three AR15's (and an FAL) that the barrels were shortened on from 20" to 16 to 18".  All three of those were unreliable right after the barrel shortening.  The closer the ports are (gas port or gas vents) the lower the pressure is going to be at the vent/port because the bullet exits the barrel sooner so the gas pulse time is shorter/lower.  On the ARs/FAL I drilled the gas ports out to the next largest size and all three were reliable.

I have no plans to enlarge the holel on any of the pistol barrels 

Ports are ports.  Size, proximity to the muzzle, caliber/pressure at the port all make a difference.

There is a difference between a compensator and porting.  Compensators catch the gas as it is popping out of the end of the barrel when the bullet is no longer blocking the barrel then the explosion is directed to mitigate recoil. Porting usually just vents gas as the bullet passes.

The position of the ports along the barrel wouldn't matter as much from a recoil mitigation perspective as they would be bleeding gas which would slow the bullet. The porting may make for a lower rise, or it may not. As for the ar, the bullet needs a certain amount of dwell time to charge the gas tube, buid up pressure and overcome the lugs and spring. If the barrel was shortened, it may not have the proper amount of time to do that. Heavy bullets with fast powder should probably work...

Of course, i could be completely wrong in all this, but everyone is an expert in the interwebs

[bravo5two]

There is a difference between a compensator and porting.  Compensators catch the gas as it is popping out of the end of the barrel when the bullet is no longer blocking the barrel then the explosion is directed to mitigate recoil. Porting usually just vents gas as the bullet passes.

The position of the ports along the barrel wouldn't matter as much from a recoil mitigation perspective as they would be bleeding gas which would slow the bullet. The porting may make for a lower rise, or it may not. As for the ar, the bullet needs a certain amount of dwell time to charge the gas tube, buid up pressure and overcome the lugs and spring. If the barrel was shortened, it may not have the proper amount of time to do that. Heavy bullets with fast powder should probably work...

Of course, i could be completely wrong in all this, but everyone is an expert in the interwebs

I believe you're correct, pistol barrel porting has only minimal effect in taming the rear ward push as the bullet exits the barrel. A compensator diverts most of that gas pressure against a baffle and to the sides.

[M1A4ME]

Ran across this the other day.  Similar discussion on another forum.

https://www.youtube.com/watch?v=3xEI36Dtf04