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Barrel porting sizes, layout, etc. ???

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porting
6K views 29 replies 10 participants last post by  DAHoyle 
#1 ·
Hey guys, I got a custom extended barrel in the works. I'm gonna have the last 1" ported.

What do you guys find work best as far as layout? equal size ports? One big and two smaller? Does it really matter?





At the moment, I'm going to have 4 equal size ports at the end of the muzzle.





thanks!
 
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#8 ·
I’m getting two large ports at the end of the barrel, and holes positioned where the fish scale lightening cuts are made in my slide. I will be firing 9mm so high pressure rounds to benefit from this. Will report back, the gunsmith said to expect 2-3” reduction in muzzle flip
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#10 · (Edited)
I’m getting two large ports at the end of the barrel, and holes positioned where the fish scale lightening cuts are made in my slide. I will be firing 9mm so high pressure rounds to benefit from this. Will report back, the gunsmith said to expect 2-3” reduction in muzzle flip View attachment 655669

Before you have this done, I stronger urge you to educate yourself on how compensators work. The holes in the barrel has been tried before, and you don't see them that much, because for one thing, they don't work as a compensator anymore than the two cuts at the end of the barrel. Your smith also doesn't seem to understand this.

Real compensators trap gas after the bullet has left the barrel and then vents it up for muzzle recoil. Nothing in your diagram will do so effectively as a normal compensated 9mm. 2-3 inches? Doubtful at best.
 
#13 · (Edited)
Right, shoot the gun before you let him mutilate the barrel.
Flip is not a limit on my rate of fire with a heavy 9mm.

Magnaport would reportedly do more.
All those holes could cost you in function.
Magnaport might work on pistols developing a lot more pressure, neglitable on 9mm. Waste of money.

Besides people using compensated 9mm pistols are usually shooting 9mm major loads, which is a whole different load than normal or even +P loads.
 
#14 ·
9mms have muzzle flip? ;)

I've made a few comps for 38 Super and 10mm, and I have found that I got the best results using chambers whose depth front to back, doesn't exceed the length of the bearing surface of the bullet being used. That and a slightly thicker septum between the comp's chambers increases the dwell time (my terminology) between chambers, thereby routing more expanding gasses up through the ports in the chambers. But I'm just a hack in a garage, so take all this with a large grain of salt. :D
 
#23 ·
thanks man, I appreciate the insightful comments on this post. The gunsmith actually scrapped the barrel while machining, so he refunded me. Maybe I dodged a bullet? ha

I have a few pistolas w/ fixed perm comps, and am always looking to experiment. I've read a study on the comparison between a comp barrel and a ported extended barrel. Both were effective in muzzle flip, with the comp being moreso. I've just never had a ported extended barrel so I wanted to compare for myself.

In response to the really helpful obvious comments on 9mm's muzzle flip, yes it has minimal flip compared to 45/38super, I'm always on the search for a flatter and faster follow up shot.

1) you dodged the bullet on wasting money.
2) Compensated 45acp 1911s are basically a waste of time. Understand that in the old/early IPSC days we were shooting ammo that was hotter then you'll find almost anyone using except maybe in a bowling pin match. I've shot compensated pistols from several well known gunsmiths of the day... muzzle rise just isn't that much different with or without a compensator. This coming from the days when anyone that wanted to be competitive in a money match HAD TO GET a compensated 70 series.

Going to run hot 9mm? or 38 super? Great.. get one properly designed and built. Slots in the barrel, holes in the barrel including magnaport won't work as well.
 
#17 ·
Ammo is a big factor in making comps work effectively.

Compensators work on gas volume. One reason why a comp on a .45 ACP is nowhere nearly as effective as on a hot, .38 Super.
Gas volume and chamber pressure are not necessarily the same thing. You can have absurdly high chamber pressure with a fast powder (think Titegroup) and the comp will work much better with lower chamber pressure from a much slower powder (like HS6) that fills more of the case.

If I'm running a comp I will try and run the slowest powder that can safely drive the bullet I'm using at appropriate speed.
Of course it is necessary to handload for this.
 
#18 ·
Ammo is a big factor in making comps work effectively.

Compensators work on gas volume. One reason why a comp on a .45 ACP is nowhere nearly as effective as on a hot, .38 Super.
Gas volume and chamber pressure are not necessarily the same thing. You can have absurdly high chamber pressure with a fast powder (think Titegroup) and the comp will work much better with lower chamber pressure from a much slower powder (like HS6) that fills more of the case.

If I'm running a comp I will try and run the slowest powder that can safely drive the bullet I'm using at appropriate speed.
Of course it is necessary to handload for this.
thanks man, I appreciate the insightful comments on this post. The gunsmith actually scrapped the barrel while machining, so he refunded me. Maybe I dodged a bullet? ha

I have a few pistolas w/ fixed perm comps, and am always looking to experiment. I've read a study on the comparison between a comp barrel and a ported extended barrel. Both were effective in muzzle flip, with the comp being moreso. I've just never had a ported extended barrel so I wanted to compare for myself.

In response to the really helpful obvious comments on 9mm's muzzle flip, yes it has minimal flip compared to 45/38super, I'm always on the search for a flatter and faster follow up shot.
 
#30 ·
While not as efficient as an Open Gun, something like the DVC P makes shooting hot 9mm “rapidly and accurately “ exceptionally easy.
It can also be carried sort of easily (think OWB).

View attachment 656725 View attachment 656727
I think I have an idea what that looks like, but could you post a pic with the slide locked back. If that was fitted tightly, it would seem it would add to lockup consistency, and thereby improving accuracy in many cases, at least as much as a well fitted bushing.
 
#26 ·
Have to ask: what pistols, what caliber and what loads?
As far as factory guns designed to run minor.

2 - STI Costa Carry Comps
1 - STI Steel Master
1 - STI Stinger
2 - BUL Armory Vipers

Interesting side note, all those guns have factory one piece barrel/comps.

As far as ammo goes I generally shoot 115gr-124gr ammo for practice. For SD I usually carry Underwood +P+ in my comped guns and carbines (yes close to major).

The rest of my comped guns were designed for other calibers or are not factory.
 
#27 ·
As far as factory guns designed to run minor.

2 - STI Costa Carry Comps
1 - STI Steel Master
1 - STI Stinger
2 - BUL Armory Vipers

Interesting side note, all those guns have factory one piece barrel/comps.

As far as ammo goes I generally shoot 115gr-124gr ammo for practice. For SD I usually carry Underwood +P+ in my comped guns and carbines (yes close to major).

The rest of my comped guns were designed for other calibers or are not factory.
Fascinating, but if it works for you....

I've shot a lot of different 9mm loads and the only one I have an real "muzzle rise" issue with it Winchester rangers in my light weight commander.

9mm in a full sized 1911 with a steel frame are mild to me. But then I have a lot of years competing with very warm 45acp ammo. I shoot 9, because it's easier on my arthritis. I'm still more accurate with full house 45acp.
 
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