Magna Port or Power Port: The Effects of Porting

Mr.RevolverGuy · August 6, 2017, 08:05 AM

This is a highly subjective experiment due to so many variables, but I still had fun. Different revolvers, recoil based on feel and no tools to measure sound. There are a few things we can learn from the data collected.

Porting & Velocity
S&W model 65 nonported always turned in the highest velocity
S&W model 19 power port always turned in the second highest velocity.
S&W model 13 magna port always turned in the lowest velocity.

Porting definitely impacts velocity and increases muzzle blast but is very effective at reducing felt recoil.

https://www.youtube.com/watch?v=T9KuKdjzDZ4

T. O'Heir · August 6, 2017, 11:45 AM

Porting has nothing to do with velocity. The bullet is out of the barrel by the time any port does anything.
A port in the middle of the barrel might cause velocity changes though. Ports don't belong in the middle of the barrel.

Nathan · August 6, 2017, 01:15 PM

Porting definitely affects velocity! Thanks for the data MRG.

74A95 · August 6, 2017, 01:45 PM

Looks like a fun comparison!

You might find the link below of interest if you have not seen it already:

http://www.shootingtimes.com/gunsmit...s-compensator/

wild cat mccane · August 6, 2017, 01:50 PM

When porting begins, that is your barrel length.

A 4" barrel ported at the last inch will likely perform at a 3" barrel for fps, all else being equal.

Mr.RevolverGuy · August 6, 2017, 03:02 PM

Quote:

Looks like a fun comparison!

You might find the link below of interest if you have not seen it already:

http://www.shootingtimes.com/gunsmit...s-compensator/

Thank you I had not seen that.

I had even more fun off camera with rapid fire between all 3 and again the Power Port reigned supreme for follow up shots.

Master Blaster · August 7, 2017, 11:45 AM

Quote:

This is a highly subjective experiment due to so many variables,

You have that right, unless you chrono'd the three guns before they were ported and after you really cannot make any general conclusions about the effect of different types of porting on velocity.

Dave T · August 7, 2017, 05:31 PM

I've owned two "ported" S&W 357 revolvers.The 3" L-comp and a limited production 4" L-comp. In both cases the recoil wasn't reduced at all but the muzzle jump/flip was reduced. Consequently faster follow-up shots were possible.

This was accentuated by the power of the load being shot. Shooting 38 Specials, even today's so called +P loadings, there was hardly any advantage to the "comp" models. Fill the cylinder with 357 Magnums and the effect could be immediately noticed.

YMMV,
Dave

FITASC · August 7, 2017, 07:25 PM

Quote:

I've owned two "ported" S&W 357 revolvers.The 3" L-comp and a limited production 4" L-comp. In both cases the recoil wasn't reduced at all but the muzzle jump/flip was reduced. Consequently faster follow-up shots were possible.

+1

tipoc · August 7, 2017, 07:37 PM

Quote:

Porting has nothing to do with velocity. The bullet is out of the barrel by the time any port does anything.

Think about this some and I think you'll see that is not the case.

Porting in general does effect velocity. But how much varies by load, bullet, powders used and the gun. Whether porting makes any significant negative impact on velocity, is questionable. It's usually not so much as to make any difference on anything you'd be shooting at.

It does make a significant impact on muzzle flip and recoil recovery though. That's usually the point of doing it.

I think the results of the video bear that out.

tipoc

rock185 · August 18, 2017, 03:20 AM

I've only shot a few ported guns, but the felt recoil was as Dave T said. Recoil was not reduced, but was more straight back/less muzzle rise. A couple of the ported guns I can recall, a S&W .41 Mag. and Benelli 12 Ga., were not that much fun to shoot due to substantial, more linear, recoil. But the the muzzle jump was reduced as advertised.

I realize to accurately compare ported and unported velocities, you'd have to test unported, then have that same barrel ported. But FWIW, we once did some chronographing with a Glock 22 and a ported 22C. With our particular guns, there was no significant difference in velocities, and sometimes average velocities with the ported gun were higher. The porting of the 22C did actually result in less muzzle rise......YMMV

Gotta say the weirdest thing I've experienced with a ported gun, was with a competition shooter's HK USP chambered in 9X21MM. It had both a comp of some kind, and a Hybrid ported barrel. The gun actually recoiled downward with each shot. The owner told me it would, but I didn't believe him before actually shooting the gun. Can't see how having the muzzle jump downward with each shot would be an advantage in competition?

arquebus357 · August 21, 2017, 03:53 PM

^^^^^^

It's easier to re-acquire a target while moving a muzzle up than moving it down.

rock185 · August 26, 2017, 03:26 PM

arquebus, thanks for the info. Never shot a ported gun in competition and did not know that.

buck460XVR · August 27, 2017, 08:49 AM

Quote:

Originally Posted by arquebus357

^^^^^^

It's easier to re-acquire a target while moving a muzzle up than moving it down.

It's also easier on the web between your thumb and first finger from heavy recoiling DA revolvers because of the reduction in "roll". I have a 6" 686 Powerport that is a very pleasant shooting range gun. When I take others to the range to shoot my guns, outta the three 686s I have(a 4", a 5" and the 6" Powerport) the Powerport is the one they pick up first the second time around.

August 6, 2017, 08:05 AM	#1
Mr.RevolverGuy Senior Member Join Date: February 24, 2007 Location: Ohio Posts: 992	Magna Port or Power Port: The Effects of Porting This is a highly subjective experiment due to so many variables, but I still had fun. Different revolvers, recoil based on feel and no tools to measure sound. There are a few things we can learn from the data collected. Porting & Velocity S&W model 65 nonported always turned in the highest velocity S&W model 19 power port always turned in the second highest velocity. S&W model 13 magna port always turned in the lowest velocity. Porting definitely impacts velocity and increases muzzle blast but is very effective at reducing felt recoil. https://www.youtube.com/watch?v=T9KuKdjzDZ4 __________________ Mr.Revolverguy http://www.dayattherange.com Firearms Reviewed and Reported On: An unbiased opinion with real world use.

August 6, 2017, 11:45 AM	#2
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Porting has nothing to do with velocity. The bullet is out of the barrel by the time any port does anything. A port in the middle of the barrel might cause velocity changes though. Ports don't belong in the middle of the barrel. __________________ Spelling and grammar count!

August 7, 2017, 05:31 PM	#8
Dave T Senior Member Join Date: April 16, 2000 Location: Mesa, Arizona Posts: 1,456	I've owned two "ported" S&W 357 revolvers.The 3" L-comp and a limited production 4" L-comp. In both cases the recoil wasn't reduced at all but the muzzle jump/flip was reduced. Consequently faster follow-up shots were possible. This was accentuated by the power of the load being shot. Shooting 38 Specials, even today's so called +P loadings, there was hardly any advantage to the "comp" models. Fill the cylinder with 357 Magnums and the effect could be immediately noticed. YMMV, Dave __________________ RSVN '69-'71 PCSD Ret

August 18, 2017, 03:20 AM	#11
rock185 Senior Member Join Date: September 2, 2001 Location: Out West in Rim Country Posts: 1,093	I've only shot a few ported guns, but the felt recoil was as Dave T said. Recoil was not reduced, but was more straight back/less muzzle rise. A couple of the ported guns I can recall, a S&W .41 Mag. and Benelli 12 Ga., were not that much fun to shoot due to substantial, more linear, recoil. But the the muzzle jump was reduced as advertised. I realize to accurately compare ported and unported velocities, you'd have to test unported, then have that same barrel ported. But FWIW, we once did some chronographing with a Glock 22 and a ported 22C. With our particular guns, there was no significant difference in velocities, and sometimes average velocities with the ported gun were higher. The porting of the 22C did actually result in less muzzle rise......YMMV Gotta say the weirdest thing I've experienced with a ported gun, was with a competition shooter's HK USP chambered in 9X21MM. It had both a comp of some kind, and a Hybrid ported barrel. The gun actually recoiled downward with each shot. The owner told me it would, but I didn't believe him before actually shooting the gun. Can't see how having the muzzle jump downward with each shot would be an advantage in competition? __________________ COTEP 640, NRA Life

August 26, 2017, 03:26 PM	#13
rock185 Senior Member Join Date: September 2, 2001 Location: Out West in Rim Country Posts: 1,093	arquebus, thanks for the info. Never shot a ported gun in competition and did not know that. __________________ COTEP 640, NRA Life

August 6, 2017, 01:15 PM	#3
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,338	Porting definitely affects velocity! Thanks for the data MRG.

August 6, 2017, 01:45 PM	#4
74A95 Senior Member Join Date: November 26, 2016 Posts: 1,573	Looks like a fun comparison! You might find the link below of interest if you have not seen it already: http://www.shootingtimes.com/gunsmit...s-compensator/

August 6, 2017, 01:50 PM	#5
wild cat mccane Senior Member Join Date: May 22, 2011 Posts: 3,629	When porting begins, that is your barrel length. A 4" barrel ported at the last inch will likely perform at a 3" barrel for fps, all else being equal.

August 21, 2017, 03:53 PM	#12
arquebus357 Senior Member Join Date: December 19, 2016 Location: Atlanta, Georgia area Posts: 455	^^^^^^ It's easier to re-acquire a target while moving a muzzle up than moving it down.