[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!

 

[Descartian]

Why wouldn’t you just buy a threaded barrel and add a compensator or take your current barrel and turn it down and use a cone comp?

Cone comps are the way to go.

 

[Uncle Bob]

Having slots cut in your barrel don't really work the way a proper compensator does because it traps gases and vents out the holes. Best compensator I've ever used was the old double D.

BTW compensators on 45acp aren't as effective as 9mm or 38 super.

 

[Uncle Bob]

Why wouldn’t you just buy a threaded barrel and add a compensator or take your current barrel and turn it down and use a cone comp?

Cone comps are the way to go.

CA. no threaded barrels.

 

[Jim w.]

An old gunzine writer said he got a Barsto barrel with those lateral slots and it was not as effective as Magnaport

 

[Uncle Bob]

An old gunzine writer said he got a Barsto barrel with those lateral slots and it was not as effective as Magnaport

Of it's 45acp, a waste of money. Magnaport does not work anything like a compensator

 

[Jim w.]

Well, the OP said he wanted superfluous holes in his barrel and can't screw on a proper compensator, so he should get the best of what remains.
Me? I'd just let the excess stick out like Rob Leatham's Pachmayr Combat Special.

 

[MuayThaiJJ]

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

 

[pistolwretch]

"the gunsmith said to expect 2-3” reduction in muzzle flip"

On a 9mm?
Careful of shooting a fast double.
Might shoot yourself in the foot!

 

[Uncle Bob]

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.

 

[Jim w.]

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.

 

[FWoo45]

I haven't experienced that much of muzzle flip to eliminate. Just my experience. A full size 9 has negligible recoil IME.

 

[Uncle Bob]

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.

 

[wrmiller]

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.

 

[Descartian]

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.

I have 6 comped guns designed to shoot regular (not 9mm major) loads. The comps work very effectively.

 

[azpoolguy]

"the gunsmith said to expect 2-3” reduction in muzzle flip"

On a 9mm?
Careful of shooting a fast double.
Might shoot yourself in the foot!

This made me chuckle.

 

[gaijin]

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.

 

[MuayThaiJJ]

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.

 

[gaijin]

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).

 

[Jim w.]

The gunsmith actually scrapped the barrel while machining, so he refunded me. Maybe I dodged a bullet? ha

Well, darn.