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Discussion Starter · #1 ·
Why do O/U barrels have side ribs?

I've never liked the look of them and thought of them as one more thing to worry about falling off, so I was wondering if they served a practical purpose.
 

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Original intention was to keep twigs and weeds from getting wedged between your barrels while hunting.

They serve no practical purpose on competition built over/unders.

There is no advantage whatsoever to using mid-ribs over a hanger system like Krieghoff or Kolar.

However, due to the design of some o/u barrels, it is impossible to use anything BUT mid-ribs to join the barrels since there wasn't enough room left for a hanger system from the beginning. They can also be used to stabilize unusually thin barrels (such as what are currently being used on the K80 Parcours).
 

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Stabilize barrel vibration and maintain POI against heat expansion from one barrel.
 

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Dissipate heat.
How can they dissipate heat when they close in the two barrels limiting the flow of air between them????
 

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How can they dissipate heat when they close in the two barrels limiting the flow of air between them????
I'm guessing radiant heat. More surface area means more cooling. So ideally, ventilated ribs would offer the most surface area and would be the best at dissipating heat.
 

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Dolby,
I would have to differ with you 100% the side ribbed barrels would retain more heat, the ventilation would be less with the side ribs less air flow for cooling than open barrels, but the side ribs would stabalize the barrels retain the point of impact in expansion if you used the under or over barrel one more than the other. The side ribs donot allow you to change the inpact point with barrel adjustments, you would have to change the impact point of barrels with side ribs with the comb adjustment.
 

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Dolby,
I would have to differ with you 100% the side ribbed barrels would retain more heat, the ventilation would be less with the side ribs less air flow for cooling than open barrels, but the side ribs would stabalize the barrels retain the point of impact in expansion if you used the under or over barrel one more than the other. The side ribs donot allow you to change the inpact point with barrel adjustments, you would have to change the impact point of barrels with side ribs with the comb adjustment.
The ribs will draw heat from the barrels and, like a radiator, provide greater surface area exposed to cooling air. So, the ribs probably cool the barrel(s) somewhat quicker. But I guess it could depend on the rib design.
 

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Twoboxer,
I speak from experience shooting an MX-3 Special O/U and an MX-8 O/U, the MX-3 Special does not have side ribs whereas the MX-8 does.. The MX-8 barrels retained more heat.
 

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I suppose that could happen if the rail is only attached to the barrel at a few points. Then it might act more as a trap than a conduit for heat.
 

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Borrow an inferred heat gun and experiment with your findings. If you possibly know a mechanic or a welder they'll have one.

Maybe the ribs are for looks. "The WOW Factor"
 

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I like the explanation skeet_man gave.

I have side ribs on a Browning, vented side rib on a Beretta and a mid-rib and hanger on my Kolar. In terms of heat dissipation and diminished mirage, mid-rib and hanger is by far the best in my experience.

Also, I am wondering if from a manufacturing perspective the use of side ribs are more efficient (material costs, labor, fitting) vs a hanger and mid-rib system? Just a thought...
 

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Ventilated ribs do not technically dissipate heat faster. The soldered rib posts actually act as heat sinks rather than to facilitate overall heat dissipation. Top ribs are designed as a visual aid to provide a flat sighting plane. Side ribs provide a larger contact surface between the barrels to stabilize them during firing just like Steve W posted. Side ribs (technically ribs between two barrels) do this very effectively....imagine a side-by-side without a rib between the barrels. Anyone seen one? O/U guns can get away without a rib between the barrels due to the strength of the monobloc but as others have mentioned, they do work well for POI consistency.
 

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As barrels have gotten thinner and thinner the side ribs are there for structural integrity. When thin barrels are not supported they will wipe and shot to shot placement is not always the best. This is what I was told way back in the early 90's when I began to design my first shotgun.

Dennis DeVault
 

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Dennis.. Remington 3200's have notoriously thin barrels and they came without side ribs. I don't know if their barrels whip, or distort, from shooting, but, I do know I shot one pretty well many years ago, and would still be shooting one for doubles if I could find anyone that made a reliable double release trigger set up for them....
 

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If you've ever seen a ultra slow motion video of the shot colum going down a barrel you would be surprised how much the barrel expands and contracts, almost like a rat swallowed by a snake.

surfer
 

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Discussion Starter · #17 ·
If you've ever seen a ultra slow motion video of the shot colum going down a barrel you would be surprised how much the barrel expands and contracts, almost like a rat swallowed by a snake.

surfer
Do you have a YouTube link for that? I think it'd be cool to see!
 

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No I don't I can't recall if it was posted here some time ago at least four years or more or if a friend copied me for a view. I don't have it my files. You may be able to do a search and find it.

Sorry I can't help. if you dig it up please post it.

Surfer
 

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Ktieghoff K-80 super sport one plantation, one gold super scrol
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what about the guns that don't have any??? are they going to fall apart (K-80)!!!
 
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