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Too much gas?


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I have a S12 that is pretty much stock other than being converted. 19" barrel, with a TAC47 auto plug. Got it tuned in, other than my eotech causing FTEs it seems to run really well. After patterning out a bunch of buckshot and running through some slugs all 2 3/4", I took it apart today to clean. I can tell the bolt comes back and contacts the area that the spring slides into from the way the residue is "cleaned off". I'm paranoid about overgassing and damaging something, so I grabbed a few pictures. It doesn't appear to be hitting hard enough to be causing damage, but this was only after 20 rounds or so. Does it just always hit, it's a matter of how hard that is the issue?

 

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The fact that the carrier contacted the rear trunnion only proves that you have sufficient gas to fully cycle the gun. What it doesn't tell you is how harshly or violently the contact was, and more importantly how much extra force and stress had to go through the front of the carrier where the op rod screws in, as this seems to be the typical failure point. You will only know if the yield strength has been exceeded when it fails, it cannot be directly inspected for signs of abuse. There should be contact of the carrier on the rear trunnion, preferably just a "kiss" and it seems foolish to wait several hundred rounds and note if it starts to mushroom. The reason that I use the distance of the ejection it gives you analog feedback that is not just a yes or a no but a variation and a scaled range. Also it is late in the process so it takes in a multitude of factors including spring pressure and drag from the magazine and new cartridge, the pressure of the gas system from that specific load, even resetting of the hammer.

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I'm not sure how far away it throws a high brass 2 3/4 shells, I've been shooting at the local range which is boxed in. I would say that they go far enough to bounce outside and forward instead of back towards me. Low brass is inconsistent and at $25/100 that is what I expect. I'll have to check distance next time I shoot.

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Also if you can't back the auto plug adjustment screw and get fte then you don't have enough control of the gas system. Look up GunFun he has an effective mod to the auto plug for magnums or it would also work if you in fact did have an over gassed gun that couldn't be tamed down by the poppet valve and spring inside the auto plug. The way he did it physically blocks some of the gas and the auto regulates the rest.

For me getting the gas system tuned is all about reliability first(including long term) and comfort second. But more importantly comfort! A well tuned gun shoots straiter, faster, and longer(who doesn't want that?)

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I'm going to need to retune the auto plug anyways, some of the FTE issues I was getting I believe were from the low brass catching the edge of the eotech. Going to put a primary arms red dot on and run the screw out until it acts up, then back in.

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I'm not sure how you attack mounts but I assembled a perfectly good working on and kept taking shit off until it started a cycle again and tried it several different times but it was always the Eotech. To work it has to be on the left side biased mount

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Its an xps2 on a cheap left side mount, but it's pretty centered. If it was offset to the left I could see that working better. Its fine with high brass but catches a low brass every once in a while. Was doing it lots until I slid it back as far as I could. I don't like how it mounts anyways, I have to take the side folder off to get the QD scope mount on and off.

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