Barrel porting sizes, layout, etc. ???

[MuayThaiJJ]

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!

Edited November 26, 2020 by MuayThaiJJ
add pics

[Midwest3Gunner]

This might get more traction in the Open gun sub forum.

[MuayThaiJJ]

Thanks I'll post it there

[MuayThaiJJ]

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!

[Whoops!]

I’m going to go deeper with this than you probably want to hear.

 

In a standard barrel, such as the one pictured, ports alone aren’t going to do you much good.

 

The ports you have pictured are some of the best you can hope for in that design, but, there is little potential material for them to work against.

 

One of the main benefits of ports is the material that is pushed against by the escaping gas.  
 

Think of the bore of a compensator as a port and the baffles as the material that is worked against.

 

In a standard barrel such as the one you have pictured, there isn’t much material for the gas to work against.

 

Bull or cone type barrels will give the ports a much larger effective area to act against.

 

In the case of the standard barrel, I would always have it threaded and put on as big a comp as possible.

 

With bull or cone barrels, lots of ports and a big comp.

 

The ports should be smaller the closer they are to the chamber.  Larger the further away.  This equalizes the amount of pressure placed on each port - makes for more even wear and more effective use of gases.

 

All to say, the ports you have pictured are fine - but they aren’t effective enough to where I’d want them - if that makes sense.

[Aircooled6racer]

Hello: The largest port should be in the first position. I have played around with comps for a couple of years and this is what I have found works best. The angle of the ports is something to consider as well. The gas slots you have shown will work but will not be as good as a dedicated comp with larger surfaces to direct the gas. Good luck on your build. Thanks, Eric

[zzt]

Barrel ports do one thing.  They reduce muzzle rise.  If that is all you are looking for, go ahead.  Slit ports are not as effective as circular.  Rather than what you propose, I'd go with a V4 configuration with 5/32" or 3/16" holes.

 

If you are looking for a reduction in felt recoil, barrel ports will do nothing.  An efficient comp dramatically reduces felt recoil and also reduces muzzle rise somewhat.

 

If you want flat and soft at the same time you have to have enough case capacity to achieve that.  9mm won't cut it.  You can have flat, or soft, but not both at the same time.  You simply cannot get enough powder in the case to 'work' the ports and comp.  38 Super, 40 S&W let you do that.  45 ACP works with max loads, but not as well as the previous two.

[Whoops!]

5 hours ago, zzt said:

Barrel ports do one thing.  They reduce muzzle rise.  If that is all you are looking for, go ahead.  Slit ports are not as effective as circular.  Rather than what you propose, I'd go with a V4 configuration with 5/32" or 3/16" holes.

 

If you are looking for a reduction in felt recoil, barrel ports will do nothing.  An efficient comp dramatically reduces felt recoil and also reduces muzzle rise somewhat.

 

If you want flat and soft at the same time you have to have enough case capacity to achieve that.  9mm won't cut it.  You can have flat, or soft, but not both at the same time.  You simply cannot get enough powder in the case to 'work' the ports and comp.  38 Super, 40 S&W let you do that.  45 ACP works with max loads, but not as well as the previous two.

 

The material being worked against is what does more to counteract the recoil.

 

It’s all physics and vectors.

 

A port alone on top of the barrel will cause the higher pressure gas left in the barrel to be on the bottom of the barrel (pushing down, counter-acting muzzle flip).

 

The metal that is pushed forward on while that gas is escaping, the forward force, is what will counter act the backwards recoil.

 

So, the slots in the top of the barrel, just like a compensator, are some of the most efficient you can get.  If they aren’t doing what you want, they should be wider to allow more gas to escape (but be careful about shaving bullets - bearing surface relative to the weight of bullet traveling down the bore - there is a point at which very bad things can start to happen). 
 

The only time a circular port would be noticeably more effective is if it is nozzle shaped and working against enough material to make it do what you want to do against the recoil (like in the Schuemann/SVI design) - a vector where slots would normally have an advantage.

 

A  vector where a comp would have the most advantage.

 

It’s all a trade off.

 

Magnaport, with their long but narrow design, is a good design for reducing flip in a standard barrel - which comes to another point -

 

If you are stuck with a standard barrel diameter and are not willing to put a comp on it - maybe forget about backwards recoil, as stated, and do something like a quad magnaport design to keep all of the high pressure on the bottom of the barrel.

 

 

It gets a lot deeper than this when referencing Eric’s points.

 

We know from flow dynamics that we want to make the most efficient use of the gas we have available.

 

Bleed off only as much as you need to get the desired effect at each port / baffle.

 

There is a minimum pressure needed for a port or baffle to make a noticeable difference counter acting recoil.

 

If you don’t have enough surface area for recoil reduction to make the most effective use of the cartridge’s available gas - then you may notice a benefit from having larger ports first.

 

But, if we have an unlimited area to work with - such as with the Binary Engineering comp - then the gas can most effectively be used with the larger ports coming last.

 

 

Clear as mud? . It’s long enough where I don’t even feel like rereading the last half of it.

Edited November 26, 2020 by Whoops!

[MuayThaiJJ]

Thanks guys here’s what I’m getting done, will report back. The gunsmith said to expect 2-3” reduction in muzzle flip

[Whoops!]

Yeah, that’s a pretty normal setup.  I think you’ll be happier with that than just the slots over the last inch.  It’ll probably take off somewhere in the vicinity of 100 fps from your 9mm ammo (with a middle to slow burn powder and 1/8” holes).

Edited November 26, 2020 by Whoops!

[Aircooled6racer]

Hello: Don't forget when you add all those holes you will loose velocity, just like using a shorter barrel. So you will need more powder to make major causing more recoil in the hand. I am not sure on the claim about muzzle flip but I am guessing you will soon find out. Thank's Eric

[ChuckS]

That thing is going to be nasty loud!