?????

**First -** Yield strength is a mechanical property of the barrel steel, it does not vary with thickness. For AISI 4150 steel in the annealed condition is around 55,000 psi, and on the heated treated condition around 90,000 to 100,000 depending on the temper.

**Second - **You obviously do not know how to calculate hoop stress. So, I will just refer you

here where a computer will do all the math for you.

Enter the following data:

15,000 = inside pressure (MPa, psi)

0 = outside pressure (MPa, psi)

.112 = inside radius (mm, in)

.152 = outside radius (mm, in)

.112 = radius to point in the wall (mm, in)

Inside pressure is the pressure inside the barrel over the pin location. this is way high but hey let's have a safety factor.

Outside pressure is actually 14.6, but it's so much less than the inside pressure it will have no influence on the magnitude of the resulting stress.

Inside radius is half of .224

Outside radius is the inside radius plus the 0.040 the OP said was how close he came to breaking through ("A little math shows I have roughly .040 between the barrel ID and drill")

Radius to point in the wall is where you want to calculated the stress, it will be highest on the inside surface, so the inside radius is used.

Results - Circumferential (Hoop) Stress: 50636 (MPa, psi)

Now, compare the resulting hoop stress to the yield stress of the steel, and the fatigue limit (both around 100,000 psi). And then remember this stress is if we had cut the entire outside diameter of the barrel down to a 0.040" wall thickness. What we actually have is a 8% section of the barrel this thin.....

The chromium plating thickness in the bore is between 0.0004" and 0.0015".

Expansion of the barrel does happen, but it is due to the internal pressure, not a bullet pushing a wave in front of it. But, like I stated before, the barrel stress stays below the fatigue limit and it can expand and contract infinitely.

Gas port leading is due to shaving, and you can have shaving with zero clearance. And, zero clearance is not a slip fit, you can get very high friction with a zero clearance fit.

You obviously do not have the engineering background necessary to understand what is important, what is not that important, and what assumptions you can make.

According to you every Government Model 1911 is on the verge to exploding every time you shoot a +P load. (23,000 psi chamber pressure, with a wall thickness of 0.062")

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