So, I continue to explore the FPE condition. I continue to be in awe of the bolt design, for some reason I like its approach.
As an aside, when you come up with a Theory, its not being presented as a fact, its a possibility, an idea, an area to explore.
You then come up with ways to test that theory. Until you can consistently repeat and predict it, until then its just a possibility. Sometimes good and sometimes not.
In my world (tech, working on generators, switch gear, fire pumps, boilers, fans AC units, as well as various frequency converters (UPS, GPU, VFD), the worst thing you can do is think your assessment is fact. You take the facts, assemble a train of logic that seems to have validity for the fault and test it. It may not pan out but the test will point you in a positive direction or show you are not getting the results you thoughts and time to rethink.
With aftermarket barrels I am not experience any of the FPE (which I think is a better term Failure of Primary Extraction descries a condition with attributing a cause.
I did get a fired case stuck in the barrel that was exact symptoms of the FPE I had experienced. I will explore that further as well. I did not think to put the wedge in the baffle to see if that would get it out.
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It lends some more evidence that its a chamber issue. Also stuck cases are over pressure signs, small chamber, rough chamber.
That said, I was coming up with larger cam throw than seems to be indicated. One suggestion was to disassemble a bolt and do a bare bolt throw check. Seems odd but will pursue that.
However, with the bolt in the gun and measuring the throw distance, I come up with .085. For those not involved in mechanical measurements and clearances , that's a huge distance. The new guns I own, have more effective throw and less babble gap that the older one. Both had the same issue (one old and one new and one it has not occurred with. It does take a fair amount of rounds (150) to get it to do that.
A thicker baffle in effect is like adding a shim albeit it not a large one (certainly not .020)
there of course is the gap on the baffle no matter how you measure it of .050. While I don't see why its there, obviously Nicholas Brewer the guy who designed it all was pretty amazing and knew what he was doing. I am not an engineer though its in my title, I am a tech. I continue to question that extraction would be weak. Others have designed extractors that are robust (as well as no extraction issues) and case heads seem to be able to take an amazing amount of abuse so designing an extraction cam that comes up short does not seem likely with someone of that capability .
Tolerance are now more than less for effective throw.
all the solutions simply reduce the free space between the baffle and the handle or receiver which gives ore extraction throw.
So it will be interesting.
In the end I may fall flat on my face, I have always learned more from my failures and equipment failures than the other way around.
It was suggest taking the firing pin out with the cocking pin and testing it. I came up with .080. Certainly well above the .035 listed. Not sure what that would prove that doing it assembled would not, same bench mark and baseline but I could have been missing something
Some more measurements and technique to get better repeatability but both methods are very close and certainly in the range of a course movement like this, even .010 should not be a factor (or if it is its a poor concept which it does not look like)
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