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I believe felt recoil is increased by forcing cones. The recoil is proportional to the sum paid for forcing cone removal. For example, if you write a check for $300.00, the actual perceived recoil is probably not noticeable. However, if you decreased your weight by 300 silver dollars, that is significant. Therefore, according to Becknell's Law of Diminishing Return, if you pay for it, you will feel it in your billfold.
 

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Nathan at "Muzzle Brakes and More" has a cool device that he uses to compare recoil of muzzle brakes. Its essentially a cart on wheels with a remote trigger. When the gun fires, the recoil sends the gun and cart in the opposite direction much like it would on your shoulder and eventually comes to rest. There are numbers on the bottom of the rail the cart is fastened to. So all else equal, if muzzle break A travels to number 20 and muzzle break B travels to number 25, muzzle brake A has less recoil.

The same could be used to test recoil of a shotgun.

 

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Nathan at "Muzzle Brakes and More" has a cool device that he uses to compare recoil of muzzle brakes. Its essentially a cart on wheels with a remote trigger. When the gun fires, the recoil sends the gun and cart in the opposite direction much like it would on your shoulder and eventually comes to rest. There are numbers on the bottom of the rail the cart is fastened to. So all else equal, if muzzle break A travels to number 20 and muzzle break B travels to number 25, muzzle brake A has less recoil.

The same could be used to test recoil of a shotgun.

I'm not sure there would be fine enough resolution for shotguns.

What you're looking for is DURATION of recoil, not necessarily the total amount.

Muzzle brakes on rifles, esp big bore rifles, have a much more dramatic effect than anything commonly used on shotguns.

That rest also has an inherent design flaw. If you slow the video to 1/4 speed, it becomes very evident that the gun is not traveling dead straight back, you can watch the gun jump up as the gun fires and in some cases bounce up and down a couple times for the first handful of inches. Since the gun is strapped directly to the carriage, the rails the carriage is riding on will bind due to the muzzle jump, imparting friction. Theoretically, everything else being equal, a brake that caused MORE muzzle jump would show a shorter distance traveled, if only due to this flaw of this flaw. Different brakes, different rotation forces and vectors, hell the same brake on otherwise identical guns with different stocks would show different results due to the stock geometry alone. I don't see how any truly meaningful comparison can be made with that rig. It can likely be improved with a ransom rest type holding device so the rotational force of muzzle jump doesn't cause the carriage to twist and torque with the gun.
 

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I would say that much (all) of the recoil is created by accelerating an object to roughly 1200fps. If the object does not move or if the object doesn't have any mass, then there isn't any recoil. While it's been a while since my last Physics class, I'm pretty sure that's how it works.
I think it was for every action there is an equal and opposite reaction.
 

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Lengthened forcing cones = thinner barrel walls at the end of the chamber. Done incorrectly, I’m fully convinced this practice (same with backboring) is the reason behind barrel failures in that area.
 

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EEB: This is a simple illustration which demonstrates that the angle of the cone exceeds the external taper of the barrel (though possibly not on a small bore or lightweight British game gun).



A barrel I transected showing the same thing; breech to right



SO chamber lengthening WILL lower the end of chamber wall thickness.
Forcing cone lengthening (by an expert) can be accomplished without lowering the end of chamber wall thickness

That said (and has been said over and over) removing metal does not strengthen a pipe. And it is very likely that the mechanical, metallurgical and ballistic engineers at Browning, Perazzi and Krieghoff designed their barrels exactly as intended prior to the magic long cone marketing hocus pocus.
 

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I think EEB and Skeet Man have it right.
It seems to me this is basically a piping fluids equation. If one lengthens the transition between bore diameters the resistance to flow will indeed be less. However, I think on a shotgun bore, while in theory this may reduce recoil, the practical effect would be negligible, due to the variance in the velocity of individual loads from the same manufacturing batch.
Further, as shown on here before, after market removal of metal from a shotgun barrel is a risky business. I have had it done ( a model 12 by Stuart Wright); but after looking at an MX 8 ,on here a couple years ago, that had a failure with a VERY thin barrel, I will no longer do it.
 

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I believe felt recoil is increased by forcing cones. The recoil is proportional to the sum paid for forcing cone removal. For example, if you write a check for $300.00, the actual perceived recoil is probably not noticeable. However, if you decreased your weight by 300 silver dollars, that is significant. Therefore, according to Becknell's Law of Diminishing Return, if you pay for it, you will feel it in your billfold.
You see the reason it doesn't work is because of the label of violence. "Forcing" cones implies coercion and this makes the shot charge unhappy. Maybe if you called it a happy slide the shotcharge would feel better about it. Also, the hotter the primer and greater the shotcharge is, the more unhappy your pellets are. This is why Stan Bakers big bore barrels work. Happy pellets mean less felt recoil. 7.5s are more prone to depression so that is why 8s have less felt recoil.

I've been sitting listening in at the gun club and it is truly amazing the B$ that you hear. Astounding!
 

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Why are we rehashing a topic of "improving" an expen$ive equipment component - your shotgun barrel - by removing metal, inviting barrel failure, and voiding any manufacturer's warranty with dubious, unproven advantages? Because we're BORED...cooped up with a blankety-blank virus and need to communicate with fellow curmudgeon "experts"...it's harmless fun! Flame away. Best Regards.
 

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If recoil is recoil, why does a muzzle brake work on a pistol or rifle?

And not that many people would know it (probably the "shotguns have lower pressure so porting doesn't work" crowd), but a muzzle brake on a shotgun would also be quite effective as well.
Ian, nobody said that, at least not me. Now we're "going somewhere else" as Neil used to call it.

Porting DOES work on shotguns just like it works on rifles and handguns. It's just not terribly effective because the percentage of recoil it has the ability to reduce is so small. It's NOT about pressure at all. It's about redirecting mass in another direction.

Here's why.

If you take the mass of the ejecta of a rifle, you have to count both the bullet and the powder (which is converted to gases under pressure, but doesn't go away.) The percentage of the ejecta made up by the gases is quite high in relationship to the overall ejecta mass. Sometimes nearing 30 to 40%. So, if you bleed off a percentage of the gases and direct some of them perpendicular to the axis of the barrel, or even backwards, you can indeed reduce the recoil substantially just because so much of the mass of the gases is being redirected in a direction that is not along the axis of the barrel.

However, in a typical target load for a shotgun, you have approximately 500 grains of shot (give or take) 30 to 40 grains of wad, and 17 to 22 or so grains of powder.

The powder makes up less than 5% of the overall mass of the ejecta.

And if, by using porting, you assume "maybe" 50% of the gases in the barrel come out through the ports (and this is a generous estimate...I think it's probably much less), you can expect about a 2% reduction in recoil.

2%

Maybe you can tell the difference. But I doubt it.

That's like the difference between a 1200 fps load and a 1175 fps load.

THAT is why porting on a shotgun is not EFFECTIVE at reducing recoil.

Not that it doesn't work. But that it doesn't do diddly squat.


That brings up an interesting tangential thought, to what affect, if any, does the forcing cone length/angle affect the velocity, and if there is a resultant change in velocity, that could be the explanation of reduced ACTUAL recoil.
As I said in my previous post; I'm not saying this is impossible. I just don't know. But what I'm saying that is that the people who say lengthened forcing cones are the cat's ass, often say that it both increases muzzle velocity AND reduces recoil. Well, you can't have it both ways. It's one or the other.

And if you are on the side of "lengthened forcing cones reduce muzzle velocity" the amount of muzzle velocity you are likely to lose with such a modification to your barrel is (in my opinion only) so low that you can't tell the difference, just like you can't tell the difference in the muzzle velocity between one shell and the next within a box of factory cartridges (I brought up my example of Winchester Universals with a range of 33 fps from among 5 shells tested.)

Hell, as one person said earlier, if that's what you're counting on, just use a little less powder in your reloads, or a lower muzzle velocity cartridge!

Why is the felt recoil of a semi-auto shotgun very nearly universally lower than a fixed breech gun of the same weight? Newtons laws say that the recoil HAS to be identical, yet I defy anyone to tell me that the recoil on a semi doesn't FEEL like it's significantly less. Same with a PFS, Soft Touch, Gracoil, ect.
Now you're going WAAAY somewhere else.

I can tell you why a gas operated semi-auto has so much less recoil, and it ain't magic. It's physics. And it's Newton's third law. (Note this discussion below does not apply to the recoil/inertial actuated semi-autos, which in my opinion do not reduce recoil very much since everything that moves inside them is low mass, and it all happens after the ejecta has left the muzzle and your shoulder has stopped the momentum of the gun.)

Inside a gas operated semi-auto is a large hunk of mass that moves every time you take a shot. It consists, in the case of a Remington 1100, of an action sleeve that is around the outside of the tubular magazine, the connecting rods that connect the action sleeve to the bolt, and the bolt itself. This is a pretty substantial percentage of the overall mass of the gun. Every time you take a shot, when the ejecta gets to where the ports are, that mass starts to move rearward. Conservation of mass means that the overall center of mass of the mechanism must stay the same until the ejecta leaves the muzzle, so while that mass of action sleeve/connecting rods/bolt are moving backwards, the center of mass of rest of the gun is tending to slightly move forward (offset by the fact that the mass of the ejecta is moving forward which is causing the center of mass of the overall gun to move rearward, as one would expect.) Overall, the gun is still moving backwards, it's just moving backwards at a slower velocity than it would be if that internal mass wasn't moving at all.

So that mass of the action sleeve/connecting rods/bolt moving backwards is what causes the recoil of a (gas operated) semi-auto to be less than a breech gun. Couple that with the fact that the action sleeve/connecting rods/bolt is NOT DONE moving backwards by the time the ejecta leaves the muzzle, which is when your body is really starting to feel the effect of the gun moving backwards, this effect is even more pronounced.

Physics works!!!

Now the recoil reduction systems are different. They are, in effect, with the use of springs or whatever they use, "flattening the curve." The overall calculated recoil is the same, it's just that it is spread out over a longer period of time. Your shoulder feels less of a jab since the peak velocity (and therefore the momentum) of the gun moving backwards towards you is reduced. The energy is converted to heat inside the mechanism by the springs being exercised.

Again, Physics works!
 

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I believe in physics, did pretty well in those classes in my educational experience. Fig’s brother Isaac was a pretty sharp cookie! For every action, etc. so, ‘splain this phenomenon. Take a 3/4” garden hose (‘bout the same ID as a 12 ga shotgun). Attach it to a water hydrant, ideally with a 1/4 turn valve. Lay the hose out on a smooth surface and turn on the water to full flow as quickly as possible. Note the reaction of the hose, pick it up and note the amount of back pressure (recoil) you feel. Turn off the water and attach a nozzle to the end of the hose. This would be ideal:
1719642

Now, turn on the water again and note the reaction of the hose and felt “recoil. Same hose, same volume, same pressure. Different reaction. Begin the explanation in 3,,,2,,,1,,,
 

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I had my Citori done about 35 years ago and my shoulder didn't notice any difference in recoil. If you want to reduce recoil have a 6° cut on the stock, 0 at the heel 6° at the toe that made a significant difference for me.
 

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I certainly can see where sending a barrel to have metal removed to lengthen the forcing cone or back bored inevitably makes the metal weaker. That's enough for me to not have it done.
I like to think that manufacturers such as Browning, who sell guns designed with lengthened forcing cones and back bored (probably just over bored) barrels have taken that into consideration in the design phase to make sure the barrels aren't structurally compromised.

All I can say is my Citori Cx that came with the lengthened cones and backbored barrels doesn't seem to have as much recoil as my dads Citori that doesn't have either of those features. Now, I can't say they are what makes the difference because mine is about a pound and a half heavier, has 30" barrels vs his 26" barrels and the comb on his has more drop than mine so his slaps my cheek because I can't get my cheek bone down on the stock and see down the rib. But in buying mine, those features had no bearing on my decision.
 

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Same hose, same volume, same pressure. Different reaction.
Except it's not the same volume. Because you have introduced a resistance to the system, the mass flow will be less.

(In my engineering life, fluid flow is kinda my "thing.")

But the difference between the two scenarios is, the stuff leaving the nozzle is traveling at much higher velocity than in the no-nozzle scenario. The two somewhat offset (mass flow rate goes down but velocity increases) but the higher velocity is the reason for the greater reaction.
 

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Except it's not the same volume. Because you have introduced a resistance to the system, the mass flow will be less.

(In my engineering life, fluid flow is kinda my "thing.")

But the difference between the two scenarios is, the stuff leaving the nozzle is traveling at much higher velocity than in the no-nozzle scenario. The two somewhat offset (mass flow rate goes down but velocity increases) but the higher velocity is the reason for the greater reaction.
I’m fully aware of your profession, that’s why I asked the question, I knew you are knowledgeable in this area. I’m thinking of the nozzle as being an extra full extended choke tube. And if we try to simulate a powder burn by turning on the hose for a certain amount of time, then shutting it off, we have the same volume of water with and without the nozzle. We’ll still get different reactions. In my feeble brain it would follow that if we restrict the flow of the ejecta from the barrel we’ll have an effect on recoil. May not be detectable or easily measurable, but it will be there. Interesting rehash of an old subject. Hope to learn something here.
 

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If a full choke tube decreases the bore from .730" to .690", that is a .055% decrease (I'm not smart enough to then calculate the resultant % of volume loss.) The garden hose with a nozzle analogy doesn't apply to a shotgun barrel. And the garden hose is markedly more flexible/expandable than a steel pipe.
 

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"Another technique for reducing recoil is the lengthening of the forcing cones in the barrels of your gun. Much of the felt recoil from a shotgun is due to friction and pressure created in the five inches forward of the chambers. It is in this area of each barrel, called the forcing cone, where the wad and shot are forced to transition from the wider diameter of the chamber to the narrower diameter of the barrel. Forcing cones that have a steeper transition will produce greater recoil. Barrels with a more gradual transition will produce less felt recoil."
Don Currie is NSCA’s Chief Instructor, an Orvis Wingshooting School instructor, and Master Class competitor.

Does this sound right?
I like what you have to say. Every gun that I had the cones lengthen reduced felt recoil for me...I recommend anyone wanting to reduce recoil have this done...FYI...have a GOOD gunsmith do the work.👍
 

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I never felt good about reaming out metal if the barrel wasn’t designed that way. If a gun is manufactured with long forcing cones that’s ok. Beretta is doing that, but I haven’t felt a noticeable decrease in recoil.
I have had several beretta' s including one that I bought used that would have cost 150K today, a three barrel live pigeon gun and the recoil was terrible. Absolutely beautiful gun and well fitted. Not for me. all of us are different. navyeod
 

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For what it is worth. Years ago I had an LC Smith trap 20 that I sent to have the engraving upgraded because I absolutely loved the gun and used it Quail hunting back when we had wild quail in the south. The engraver sent my gun to a gunsmith in New England to get it annealed so he could engrave it. The gunsmith called me and told me I had to stop shooting 2.75 shells through it as it has 2 5/16 chambers and the barrels were slightly expanding. he recommended rechambering and lengthening the forcing cones. I had never heard of forcing cones so after talking to him and being convinced that he really seemed to know his business {much better that me} and the cost to lengthen the cone was no more, I agreed. The gun was returned to him by the engraver and when he reversed the annealing the gun did not fit. He told me this and it made me sick. i had bought the gun from a Colorado gunsmith who was dying and had kept this gun for himself to restore in the future . The fit was close to perfect. but when the gunsmith sent the gun back to me it was just as good as before and no extra charge. The gun was the best shooting I ever had. would use the double A's target loads and was amazed the range on doves and quail. I could tell the difference and people would be amazed also at the long range shots that the gun would make. I know this is anecdotal but I did not pay extra for this. and have this gun today after 35 years. navyeod
 
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