Cylinder wall thickness

[nipperdog]

I was cleaning my new Model 69 5 Shooter yesterday and noticed that the inside to outside Cylinder Wall looked pretty thin for a .44 Mag. I measured it with a caliper and got .060. I'm curious what the Cylinder Wall thickness on a Model 29 is in comparison.

 

[arjay]

Approx. .079 on a pre 29

 

[MichiganScott]

You need to remember that the cylinder stop notch on a Model 29 is the thin spot, not the cylinder wall itself. I don't have the tools to actually measure the depth, but I believe I read that it is about the same as the cylinder wall on your Model 69, and maybe even less.

 

[Paul105]

From Brian Pearce's recent article in Handloader Mag (Dec 2014, No. 293):

Due to location of bolt notches (chamber wall thickness at weakest point is .040” in 629 vs. .052 in M69) cylinder strength is more than adequate to handle .44 Mag pressures.

FWIW,

Paul

 

[BLUEDOT37]

The weak point

With the stop bolt notch inbetween the chambers on the 5 shot M69/696/396, the notch depth isn't a factor for it. You have full outer cylinder wall thickness available for strength. Five & seven shot revolvers are blessed with this trait.

My 629-6 has .077" outer wall thickness but the stop bolt notch is .038" deep so that leaves .039" metal thickness at that point. My 657-5 has .048" thickness at that point (under the notch) while my 25-13 only has .026" there.

.

 

[k22fan]

In 6 shot S&Ws the first thing to distort beyond its elastic limit is the bottom on the stop notch. The result is dimples under the stop notches and difficult extraction because the case walls swell to fit the dimples. I’m not proud of how I learned this.

N frames with the endurance package have long stop notches. That makes the thinnest portion of the cylinder wall a rectangular area rather than the bottom of a simi-circular cut or arch. Logically, everything else being equal, a 6 or 8 shot N frame with the endurance package will dimple at a lower pressure than one without the long stop notches.

That makes it incorrect to say the newer revolvers with the endurance package are stronger than older ones. The endurance package made N frames hold up better under heavy recoil, but did not make them able to handle higher pressure.

Off topic perhaps, but hopefully of interest to reloaders.