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Hammer1 Offline OP
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What does porting shotgun barrels do to patterns ?


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From my experience, it doesn't affect patterning.
I've literally shot dozens of ported Rem 870's that were wearing Vang Comp barrels. Take a look at Hans Vang's website.

https://vangcomp.com/Home.html

Ed


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The porting is supposed to do two things: One, it�s alleged to control muzzle jump, and two, it bleeds off gas/pressure behind the wad, slowing the wad and letting the wad separate from the shot column. Letting the wad separate from the shot column is supposed to lessen any influence the wad may have on the shot column and enhance downrange patterns.

Addressing number 1: Shotguns don�t operate at a high enough pressure for the porting to lessen the muzzle jump.

Addressing number 2: I used to think that was sound reasoning until Federal perfected their Flight Control Wad (FCW). Federal�s FCW is designed to stay with the shot column long after leaving the barrel. The wad has 4 little fins that spring open after it clears the choke, and the fins act as air brakes and slow the wad down. The secret to success using Federals FCW ammo is to use a smooth choke with no wad-stoppers in it. Wad stoppers and porting will tear those little fins up on the FCW, and when it exits the barrel, one or two of the fins may spring open but the other two are damaged. This causes the wad (with the shot still in it) to yaw, disrupting the pattern.

I had Rhino make a non-ported choke for my daughter�s 20 gauge expressly for the purpose of using the Federal FC Heavy Weight #7 shot shells. She killed a turkey at a laser-measured 68 yards. That Federal FC Heavy Weight ammo throws some unbelievable patterns if you use the right type of choke and the right constriction.

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With modern shells and the plastic shot cups, I don't see how porting coudld affect patterning.

Noise? Probably increases it.


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Porting does affect patterns; it causes erratic patterns. I'll never own another ported shotgun barrel. The only benefit I could see would be reduced muzzle rise, or muzzle flip/jump, but porting on a shotgun barrel doesn't even do that; the operating pressures of shotguns are too low for any porting or a muzzle brake to have any effect.

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Originally Posted by Hammer1
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What does porting shotgun barrels do to patterns ?


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Not much in my experience. Porting is one of those fads shotgunners fell into and it is the "cool" thing to have ported barrels on your sporting clays gun, ect. If ya really want to be cool on the shooting line at a shotgunner event have a long barreled (think 34") O/U with ported barrels and the longest ported chokes screwed in you can lay hands on. But if you can't smash clays with such a rig... then you have no excuses! My opinion is that ports in a barrel really don't have much practical function, are noisy, and make cleaning more of a chore.


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Originally Posted by MOGC
My opinion is that ports in a barrel really don't have much practical function, are noisy, and make cleaning more of a chore.

The ports can, in theory, slow the wad down by lowering the pressure behind the wad as the wad passes by the ports. The ports can also tear and pull at a wad which can't be good for pattern density.

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Originally Posted by Gene L


Noise? Probably increases it.


No doubt about that. I had a Mossberg 835 Ulti-mag for about half a duck season. It was factory ported and just brutal in a duck blind.


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You can probably deduce my opinion of ported barrels from the fact my Browning XS is the only one I know of without ports...... FWIW, Dutch.


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Porting WILL reduce muzzle jump in shotguns, and porting WILL decrease felt recoil.

In the 80's and 90's I was shooting Trap and Skeet competition. I was shooting 10,000+ shotshells per year for most of those 20 years.

Both my single barrel Trap gun, a Browning BT-99, and my Trap doubles and Skeet gun, a Browning Citori, came from the factory with solid, unported barrels. I had the BT-99 Angle ported and the Citori Pro-ported. When I had them ported, there DEFINITELY WAS a noticeable reduction in felt recoil and in muzzle jump.

There is also a noticeable reduction in felt recoil with the Angle ported BT-99 over the Pro-ported Citori shooting the same shells, even though the Citori is a heavier gun which should absorb some of the recoil.

The ports in shotgun barrels are in front of the chokes. Therefore if the ports did affect the wad, that would all be changed when the wad passes through the choke. Also, for this discussion, I shot two 12 ga target shells, from the same box, into the air and recovered the wads. One shell was shot from my Pro-ported Citori with a Skeet choke. The other shell was shot from my un-ported Rem 870 that also had a Skeet choke. I cannot see any visible difference in the wads, even when I examined them under my 3x magnifier light.

As for porting increasing muzzle noise, I just don't see (or hear) that happening.

In the 200,000+ rounds of Trap and Skeet that I have shot (and still shoot +/- 100 shells every Wednesday evening) I cannot tell by the muzzle noise if a gun is ported or not. I have to look at the muzzle and see if the barrel(s) are ported.

HOWEVER, every fall just before bird seasons (like now) we get many shooters who haven't shot their shotguns since the end of last bird season, and want to shoot a box or two before going hunting. I have never seen any of shooters with a ported field gun, but you can instantly tell when one of these shooters shoots his field loads. They are VERY NOTICEABLY LOUDER than standard target shells, even if the target shells are shot in a ported barrel.



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Good post buffybr. Thanx.


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I had a Beretta Xtrema shotgun I bought for turkey hunting. After shooting a box of turkey loads I determined that the amount of recoil was beyond what I was willing to tolerate. I sent my shotgun off to Angle Port where they back bored it and angle ported it. It didn't make any difference that I could tell.

Shoot some of the Federal Flight Control ammo through a ported barrel or a ported choke. The porting rips the [bleep] out of the wads and royally screws up the patterns.

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I ported an 1100 barrel on a shotgun I used for IPSC three-gun events, and it helped keep the muzzle down. It was quite effective on plates and poppers. I did it myself, and put more ports on the right side than the left. Being right handed, the gun would normally recoil a bit to the right and up. When I got done with that barrel, it actually would "push" the gun to the left, it would just "walk" left across a falling plate machine, if you just laid the forearm across your open hand.

Shotgun barrel steel isn't very hard, I did that with a B&D drill, 1/8" bit, and eyeballing things. I found an old barrel at a gun show, and didn't have but about $30 in it, so I had little to lose. It didn't effect patterns out of that barrel, but I'd smoothed the burrs out of it before trying it out.
The other competitors laughed at it, until I whipped 'em with it.


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I agree with Buffy.
Vang's porting does help in reducing muzzle jump.
I've been working with several shotguns this summer, and in doing a three-gun project a few weeks ago I noticed quite a bit of difference in hotter buck & slug loads between one 870 that was worked over by Vang long ago, and an un-modified 870 PMAX, both with the same 18-inch barrel lengths.

As far as pattern effects go, porting CAN slow down a shot charge or slug fractionally, but most of the bleed-off occurs so close to the muzzle that I'm not sure how much real effect it has, IN ITSELF, on velocities.

The backboring that Vang does probably has more affect on lowering shot charge speeds than the porting alone, but together they do slightly reduce velocities.
The combination of porting, backboring, and forcing cone lengthening all combine to reduce recoil, too.

That project inspired another one, where I fired several different buckshot loads through the PMAX at various distances & measured results, then sent just the barrel to Vang to be worked on.
When it came back, I repeated the earlier baseline protocol.
Patterns were markedly tighter on the second go-round with almost all loads, muzzle rise/cheek slap was also reduced.

The potential for erratic patterning is greatest in the Flitecontrol loads, since their wad is designed to perform to certain parameters that depend on velocity/gas pressure, but even there the second session showed overall tighter patterns with most of the Flitecontrol loads tested.

Working with three Remmies, a Savage, the new Beretta, and a Stoeger coachgun, all in 12-gauge, has shown more pattern variations this year than I've ever encountered before, with some individual buckshot loads actually patterning tighter at progressively farther distances than at closer distances.

Shotgun performance is highly variable, but my experience shows me an overall trend- The Vang Comp barrels produce tighter shot patterns in general than the standard factory barrels I've worked with, and show lower recoil levels.
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Denis: Do you have a sense as to whether the perceived reduction in recoil using the Vang Comp barrel is due to porting or lengthening of the forcing cone?

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Originally Posted by DPris
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The backboring that Vang does probably has more affect on lowering shot charge speeds than the porting alone, but together they do slightly reduce velocities.
The combination of porting, backboring, and forcing cone lengthening all combine to reduce recoil, too.


Just curious as to why you think that backboring reduces velocity?

My area of interest lies in sporting clays vs defensive shotgunning, however I've run tests that show just the opposite with target and hunting loads.

I took a set of 34" Perazzi barrels that were aready overbored from the factory @ 18.7 mm (.736") and had Briley lengthen the forcing cone and backbore to .745" and ream the chokes to the original configuration (23 and 32=tight Mod and slightly tight Full).

Velocity of 7/8 oz Rio target loads increased by an average of 37 fps. Velocity of 1 1/4 oz Kent Fast Lead Pheasant loads increased by an average of 20.3 fps.

In both cases the patterns showed more pellet strikes in the 30" circle at 40 yards.

In both cases muzzle rise (as recorded by time lapsed photo of a lamp mounted on the muzzle) decreased by an average of over 20% with extreme shots exceeding 30%.
And that's in barrels that were not ported.

Full details in December (2009) Sporting Clays Magazine.

I can't imagine a reason that anything would differ with buckshot and/or slugs. Have you chronographed (or seen detailed reports) of before and after velocity results with buckshot/slugs??? I'd be curious.
Greg


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Grand,
Perceived recoil is dual-directional, you feel it in your shoulder as the gun attempts to move straight back, and you see it in the muzzle as it rises because the gun can't move entirely in a straight rearward position.

When we talk about reducing recoil, it's necessary to separate out what the two elements are that Vang's barrel work addresses.
The ports push the muzzle down, which reduces that part of the recoil you see and feel against your cheek.
The internal backboring & cone lengthening mechanically reduce the actual back-thrust that occurs when the shot charge first enters the cone (spreading it out over a longer compression period) and again when it enters the now-oversized bore.

Although it all happens too fast to register when the gun fires, those two "compression" points create part of the recoil that results.

Long way of saying that the porting acts in conjunction with the internal barrel modifications to reduce both aspects of perceived recoil, the part you feel on the shoulder and the muzzle rise.

Porting alone would address the muzzle rise, but wouldn't be as effective in overall recoil reduction as the full treatment.
Another note on porting is that not all ports are equal. Drilling CAN leave burrs, which would tend to tear up plastic wads, IF not polished out.

I didn't see any wads, conventional or Flitecontrol, that showed unusual deformation or tearing after porting.

Gmoats,
My occasionally hazy memory from the first shotgun Vang worked on for me about nine years ago thinks something was said at the time about the backboring acting to reduce velocities somewhat, and I added that to an email conversation with one of Vang's shop guys about the recent barrel work where he said velocities are lowered slightly as the end result of their modifications.

Could be wrong on the backboring & cone affecting velocity, but the overall effects I experienced in recoil & patterning still apply. smile

I have not chronoed any buckshot loads. Never had the interest in taking the time. smile

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Originally Posted by buffybr
Porting WILL reduce muzzle jump in shotguns, and porting WILL decrease felt recoil.

In the 80's and 90's I was shooting Trap and Skeet competition. I was shooting 10,000+ shotshells per year for most of those 20 years.

Both my single barrel Trap gun, a Browning BT-99, and my Trap doubles and Skeet gun, a Browning Citori, came from the factory with solid, unported barrels. I had the BT-99 Angle ported and the Citori Pro-ported. When I had them ported, there DEFINITELY WAS a noticeable reduction in felt recoil and in muzzle jump.

There is also a noticeable reduction in felt recoil with the Angle ported BT-99 over the Pro-ported Citori shooting the same shells, even though the Citori is a heavier gun which should absorb some of the recoil.

The ports in shotgun barrels are in front of the chokes. Therefore if the ports did affect the wad, that would all be changed when the wad passes through the choke. Also, for this discussion, I shot two 12 ga target shells, from the same box, into the air and recovered the wads. One shell was shot from my Pro-ported Citori with a Skeet choke. The other shell was shot from my un-ported Rem 870 that also had a Skeet choke. I cannot see any visible difference in the wads, even when I examined them under my 3x magnifier light.

As for porting increasing muzzle noise, I just don't see (or hear) that happening.

In the 200,000+ rounds of Trap and Skeet that I have shot (and still shoot +/- 100 shells every Wednesday evening) I cannot tell by the muzzle noise if a gun is ported or not. I have to look at the muzzle and see if the barrel(s) are ported.

HOWEVER, every fall just before bird seasons (like now) we get many shooters who haven't shot their shotguns since the end of last bird season, and want to shoot a box or two before going hunting. I have never seen any of shooters with a ported field gun, but you can instantly tell when one of these shooters shoots his field loads. They are VERY NOTICEABLY LOUDER than standard target shells, even if the target shells are shot in a ported barrel.



I'm of the same thoughts.


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