doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com GunsmithsQ. Bbl torque,when firing one bbl on sxs

I was reading Stans topic on his off face BSS.
I was wondering when you fire the right bbl,do the bbls torque to the left or right, as your looking down the rib & pulling the trigger?.
As they are offset from the middle, or rib, there has to be some difference depending on which bbl is fired.
I would think that right bbl firing would make the bbls torque to the left?
And if a gun was fired thousands of times , from the same bbl only,like a single shot, would that cause the fired bbl to come off face...or the other not used bbl?
Cheers
franc

Of course there would be torque to the right or left. And many other vibrations and harmonics as well. I think there was a good discussion about the dynamics of firing in "Shotgun Technicana" by Michael McIntosh and David Trevallion. There is a lot of movement going on even though the gun appears perfectly locked closed. I believe as Miller does, that most wear occurs from a lack of proper maintenance, i.e., lack of cleaning and proper lubrication of hook and hinge pin joint. But when contact points are pounded thousands of times with thousands of pounds per square inch of force, there is bound to be some slight deflection of metal. Even bearings that are filled with grease can suffer damage such as Brinneling, etc.

Hi Keith, Like I said,I realize there is torque, but if right bbl is fired , do the muzzles want to kick left?..that was my question
cheers
franc

AND there is no fixed axis position
The shooter moves with the momentum
Mike

As Kieth wrote, "there is a lot of movement going on," and SxS are believed to flex in the vertical axis. SxS almost always have the trigger for the right barrel forward on the theory that there is less felt recoil from the right barrel(for a right hand shooter) because the barrel will pull away from the cheek. This is because the right barrel is to the right of the center line on the stock.

I see. Sorry I misunderstood the question. According to what I read in "Shotgun Technicana", as I recall, the initial movement of the muzzles would be to the left when the right barrel is fired, and vice-versa when the left barrel is fired. This makes sense to me since the back thrust against the breech would be to the right of center when the right barrel is fired. And recoil generated by the sudden acceleration of the mass of the ejecta would initially move the gun rearward and the muzzle end upward, with rotation at the point of the shooter's shoulder. This rotation would naturally be greater in a gun with more drop at heel. Since steel is a somewhat springy substance, there is a rebound to all of these movements. There are apparently many oscillations and vibrations going on in the milliseconds after detonating a primer including the mysterious forces that cause phenomena such as rivelling of barrels.

Lads
I'm sorry if I'm being a bit Thick as a Brick (or Britt)..ala Jethro Tull
but if you fire the right bbl, & the muzzles moves away to the right, wouldn't that make the back end,the stock where your jaw is move the opposite way, like left...into your face?...though the butt is kinda anchored at the shoulder
Like if you put a 2x4 up in gun mount n someone wacked it with a hammer,at the far end, to the shooters right, I think you'd feel it in your jaw?
Im not trying to be a jerk, just honestly interested on what goes on when a gun is fired regarding left to right recoil
cheers, & thanks for your replies
Franc
franc

Thanks Keith, its all very interesting, what happens in those milli seconds when the hammer fall, eh?
cheers
franc

Well let's see now. It seems to me the pivot point for the gun is going to be at its point of contact with the shoulder. Assuming no cast & the but fitting the shoulder squarely (Neither of which is a universal given) then this pivot point could be extended forward down the center of the gun. As the axis of the bore for the right barrel would lie in its entirety to the right of this line then the natural tendency would seem to be for it to swing to the right on firing. Vice/versa of course for the left barrel. Due to the fact that on all doubles I am even remotely aware of the barrels converge toward the muzzle it would appear the major movement at least follows this general theory as they still shoot essentially to point of aim. There are of course other minor movements occurring due to barrel flexibility etc, but this would seem to be the major one. This would tend to move the stock away from the cheek in firing the right barrel & toward it when firing the left. It will of course rise when either is fired & to a greater extent than the side movement. There is of course the matter of barrel Whip to consider. This occurs as the gun starts to move in one direction the flexibility of the barrels will cause the muzzle to lag or even move in the opposite direction. This can be easily visualized by holding a fly rod out in front of you. With a good grip ion it flip your wrist to one side while watching the tip. You will not it move at first opposite of the way you moved the butt. It would seem to me that the barrels would be stiffer, thus less whip, in the sideways direction than vertical & also there would be more impetus given in the vertical direction. As said though there is a lot going on that cannot truly be seen..