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Thread: Carbine vs. Middy: Real world use

  1. #111
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    Quote Originally Posted by An Undocumented Worker View Post
    Erosion in a blast baffle of a compesated rifle is no different than the erosion of an exhaust valve of an automobile with a leaking exhaust manifold. Typically the exhaust is mostly free of O2, yet still has some unburned fuel in it. If there is a crack in the exhaust manifold near the head, as the pressure wave reverses, oxygen is sucked into the manifold and impinges against the exhaust valve, this O2 superheats the exhaust locally (due to the unburnt fuel in it) where it starts cutting the valve like a plasma torch. That is essentially what is happening to the blast baffle of a compesator/suppressor. Not cavitation.
    You are correct. I didn't intend to insinuate that cavitation caused erosion in a suppressor, but rather was accenting the abraisiveness of un-burnt power/gas as it flows through the barrel and gas system of an AR (relating to the original comment about balsa-wood-like consistency.)
    Semper Paratus Certified AR15 Armorer

  2. #112
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    So essentially, back-pressure against the bolt lugs from the case cause it to stay locked. The lugs unlock when the pressure @ the key becomes higher than the residual pressure in the bore?
    No. The bolt begins unlocking when the angle in the slot of the carrier engages the bolt cam which turns the bolt. This will happen regardless of pressure. A properly designed system will be timed that pressures drop to safe levels before it begins unlocking the bolt.

    The AR bolt is locked mechanically in the barrel extension. The slot in the bolt carrier keeps the bolt cam positioned so that the bolt does not rotate and unlock during firing.

    brass case shrinks What causes this?
    Brass is elastic and expands to completely fit and seal the chamber from the pressures during firing (sticking it to the chamber walls, reducing back thrust on the bolt face), then shrinks somewhat when the pressure drops. Brass is also malleable and does not return completely to it's original dimensions. The outside dimensions of a brass case will be slightly larger after it was fired than it was before. It will not shrink to a size smaller than it was.

    The elasticity of brass is greater than steel, one of the properties that makes brass cases superior to steel cases
    INSIDE PLAN OF BOX
    1. ROAD-RUNNER LIFTS GLASS OF WATER- PULLING UP MATCH
    2. MATCH SCRATCHES ON MATCH-BOX
    3. MATCH LIGHTS FUSE TO TNT
    4. BOOM!
    5. HA-HA!!

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  3. #113
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    Quote Originally Posted by MistWolf View Post
    No
    The elasticity of brass is greater than steel, one of the properties that makes brass cases superior to steel cases
    This is fact. I've tried resizing Wolf Steel cases just to try it. They suck at getting squeezed back down to size.
    "You people have too much time on your hands." - scottryan

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