Revolver vs. semi-auto bbl length measurements

[TarpleyG]

I have a question. I just measured the length of the barrel on three of my guns to compare how the stated barrel lengths stand up to the actual length. I measured by unloading the gun and placing a pencil in the barrel and marking it when it hit the breech face. Here are my observations.

S&W 65LS 3" bbl - Actual length is 4 11/16" with the same sight radius.
Kimber Pro Carry 4" bbl - Actual length is 4" and sight radius is longer.
Kimber TLE 5" bbl - Actual length is 5" and the sight radius is also longer.

Now, it seems to me that the stated length of revolver chambers and barrels are a lot longer than what the model states. Why is this? How come they only measure the barrel and not the chamber on revolvers but they measure the whole thing on semi-autos? I effectively have the same barrel length using my LS than I do when using my 1911. Does the cylinder gap figure in to this equation when determining velocity, pressure, etc.?

Greg

 

[355sigfan]

Because the revolver barrel is sold as just the barrel not the chamber. With autos the chamber is integeral to the the barrel and is sold as a unit.
Pat

 

[4thHorseman]

Does the cylinder gap figure in to this equation when determining velocity, pressure, etc.?

I have heard this question several times before.
My understanding there is a slight velocity loss (approx 50 fps) because of the cylinder gap.
Whether or not it equates to a semi auto and it's recoil loss I'm not sure. My guess would be pretty much the same.
I figure it is already calcuated in the gun/caliber design during manufacturing and design. By that I mean when a caliber is first designed it is designed with the loss already calculated for and the caliber is adjusted from there to reach the specs desired by the manufacturer.