[GaryP]

So I have a new single action revolver. It seems to have excessive cylinder gap, but does it? What happens internally when a round goes off? The pressure rises rapidly and the bullet starts down the chamber. Before the bullet leaves the cylinder to enter the barrel, there is a large force pushing that cylinder forward. It will take up all the slack in fore and aft cylinder movement and minimize the gap. The cylinder gap is the gap with the cylinder pushed forward. Visually, about half the slack gap.

Another way to consider this, suppose I cut the top and bottom of the frame and hold the cylinder in place with a rod threaded to the back of the frame. A little friction to hold the cylinder in place so ithe remnains of the gun can be fired. One is going to launch the entire cylinder into space. This extreme example shows the cylinder moves forward when the gun is fired. The cylinder gap is the gap with the cylinder pushed forward.

Is this something so obvious no one ever mentions it? I don’t think so, I cannot find anything in a search.

The forward motion of the cylinder on my gun is controlled by an extended portion at the center of the cylinder. I think I will order a spare cylinder and machine down that center by amount of the measured gap with the cylinder pushed forward minus 0.002 inches. Effectiveness will show up in increase bullet velocity and reduced cylinder flare.

 

[MagDump]

You don’t read anything about this because there is no force pushing the cylinder forward. All forces once the primer ignites move the revolver rearward (with some upward movement depending on grip). The case grips the cylinder walls holding it back until the pressure drops enough for inertia to take over - all after the bullet has left the barrel. The only time the gap is markedly reduced during firing is when the bullet bridges the gap.

My Dan Wesson demonstrates this, I can set the cylinder gap so that when the cylinder is held forward by my hand there is no gap - yet when fired the blast from the gap is substantial because the cylinder is pushed rearwards.



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