What is the purpose of the ribbing on top of the barrel for field shotguns?

[Skribs]

http://www.benelliusa.com/shotguns/benelli-supernova.php

To give an example of what I'm referring to, there is nothing on top of the barrel of the supernova tactical (with the exception of the front sight), while the field gun has what looks like a ribbing all along the top of the barrel. Pretty much every site I've looked at follows this suit - "field" guns have a 26-28" barrel with this thing, "tactical" shotguns have a 18.5-22" barrel without it. (The exception is the remington 1100 tactical).

What is this thing called, and what it its purpose? (Not knowing the name for it is also causing me difficulty in looking up its purpose).

 

[oneounceload]

It is called a "rib" - it is designed to dissipate heat mirage from the barrel. Some folks like to use it as a sighting plane. Some, like your picture, are "vent rib" versions, others are "solid rib". SxS guns can also have a "swamped rib", "raised rib", or "raised vent rib"

 

[birdshot8's]

The rib gives you a smooth plane as you look over the barrel at the target. The ventilated rib aids in cooling the barrel, so you don't have to look through heat waves as you swing on your target.

 

[leadcounsel]

I also imagine it must add some strength and integrity to a long thin barrel - after a day of shooting trap, a person might lean his gun against a wall or tree and warp the barrel. But with the vented rib, a cool piece of metal may prefent the barrel from warping.

 

[jmr40]

At one time they were only used on competition guns that were shot enough for heat to build up. Most hunting guns used plain barrels. For whatever reason hunters started wanting guns that looked like the guns the target shooters were using. The trend was pretty well in place by the 1970's.

Whether it is really of any benefit to hunters or not is debateable, but they have become so standard that most, including myself, don't like the looks of a gun without them.

 

[rcmodel]

I thought everyone knew vent ribs are there for mud to collect under on duck guns.
And weed seeds to collect under on upland bird guns??
And get bent when your bird dog knocks it over??

My old Browning A5 has a solid matted rib so I don't have to deal with it.

rc

 

[jmr40]

No, the vents let air flow through cutting down on wind resitance when swinging. They can also be used to place brush in to camoflage your barrel when turkey hunting.

 

[allaroundhunter]

I also imagine it must add some strength and integrity to a long thin barrel - after a day of shooting trap, a person might lean his gun against a wall or tree and warp the barrel. But with the vented rib, a cool piece of metal may prefent the barrel from warping.

It takes a heck of a lot of heat to cause a barrel to be weak enough to warp. And no shotgun used in its typical manner will ever get that hot. Heck, you can put it through a major torture test and I don't think it will get that hot.

 

[oneounceload]

I also imagine it must add some strength and integrity to a long thin barrel - after a day of shooting trap, a person might lean his gun against a wall or tree and warp the barrel. But with the vented rib, a cool piece of metal may prefent the barrel from warping.

Folks who go to Argentina on dove shoots can put thousands of rounds through their guns in a single day - it still isn't going to warp the barrel

 

[jaguarxk120]

The Browning A-5 autoloader's with the plain barrels have a croshatch texture along the sighting plane. That texture helps to reduce any reflections from the barrel surface.

 

[Dave McCracken]

Some thoughts....

First, I've shot well with ribs varying from none to railway trestle,including swamped ribs, solid ribs, vent ribs, and the vaunted Browning Broadway, which is akin to mounting a 1X2atop your barrel.

All ribs add weight. All ribs connected to the barrel act as heat sinks, thus different points on the barrel expand and contract at different rates.This may be important, I've not tested POI issues enough to know.

All ribs aid in protecting against heat mirage. This is important in competition,but field guns rarely are fired fast enough to need protection.

Vent ribs on field guns are more marketing than need. If the makers can charge more for a barrel with rib, and convince folks ribs are crucial, then.....

Were I getting a cost is no object upland gun, it'd be an alloy framed 20 gauge O/U with 30" barrels and no rib. The top of the top barrel might be matted to reduce glare.

I note FABARMS has a new target semi out with bellsnwhistles Galore. While the vent rib only touches the barrel at receiver and muzzle, there's a thin strip of steel laid down the barrel to "reduce heat distortion".

Maybe, maybe not. I'd have to fire it vs a non equipped barrel to find out.

 

[allaroundhunter]

Folks who go to Argentina on dove shoots can put thousands of rounds through their guns in a single day - it still isn't going to warp the barrel

I will let you know for sure this summer

 

[WardenWolf]

With my Winchester 1300 20 gauge, I used to sight down the side of the rib. Was much easier to do that than with the sight bead.

 

[interlock]

i like some of the entertaining answers to this question. I have a miroku mk70 sporter with a narrow solid rib. I thinky it is just good to look down when shooting. I see trap guns with lots of differeing styles and sizes of rib... i am not sure how much they help.

 

[303tom]

Simply a sighting plane................

 

[bubba in ca]

My hd gun has a vent rib because in a hurry at close range I`m not going to see the useless little sights and I sure don`t need the rifle sites on my other shotgun to get in the way. When you practice with a vent rib on a gun that fits you, you use the vent rib as the sight. You are shooting felons at 0 to 20 feet, not targets at 100 yards.