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AR10T case rim strike - issue?

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Replied by OleCowboy on topic AR10T case rim strike - issue?

I noticed same same. It light but clearly there and its visible on at least 3 of them.
10 years 1 week ago #37032

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Replied by MrMarty51 on topic AR10T case rim strike - issue?

The angle and the light on the third from left casing makes the mark almost invisible.
I did`nt see it on that one at first either. :busted: :rotfl:

Might be a thing as "Tired eyes" for Me. :whip: :rotfl:
Things is moving fast now.
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10 years 1 week ago #37034

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Replied by jtallen83 on topic AR10T case rim strike - issue?


That mark appears to be from the extractor cutout on the bolt face, I think......
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10 years 1 week ago #37054

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Replied by delta6 on topic AR10T case rim strike - issue?


Good suggestion. Definitely marks made by extractor and ejector. Over gassed or hot loads?
Have you mic'ed the cases to check OAL once fired?
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10 years 1 week ago #37077

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Replied by SOC on topic AR10T case rim strike - issue?

Basically your cases are still under pressure while the bolt starts to unlock. This gives the circular mark and scrape. Since the case hasn't contracted and let go of the chamber walls while the extractor is trying to pull the case out it is bending the rim.

This is commonly interpreted as overpressure issue when in fact it is not.

PPU ammo in general uses a relatively slow burning powder so the case stays pressurized longer. Not an issue in bolt guns.

Try ammo loaded with a faster burning powder and you will see this issue stop.
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10 years 1 week ago #37087

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Replied by MrMarty51 on topic AR10T case rim strike - issue?

I had been concerned about some of My reloads, but, I have not seen any marks like this on the casings and they have all cycled well, I guess I am OK with My loads then.
I did get a chrony, so, next journey to the range will be setting the chrony and firing some rounds through it to see what is really going on.
Things is moving fast now.
What`ll You say when Jesus asks, Why did`nt You read My book ???
10 years 1 week ago #37088

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Replied by blazermark on topic AR10T case rim strike - issue?

Thanks to all for your feedback.
Armalite tech responded with 'not of concern', and a phone # to contact an individual for more info.

I will get out again with some different ammo and post the case's ...
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10 years 1 week ago #37090

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Replied by blazermark on topic AR10T case rim strike - issue?

got out again, and ran another 10 rounds thru (5 & 5) ..

used some Norma this time, better results on the brass.. still beating the rim up a bit, but I'm thinking I will continue with break-in and get to about 200 rounds and see where it is..


10 years 1 day ago #37358

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Replied by jtallen83 on topic AR10T case rim strike - issue?

I loose about 30% of my cases to bent rims, they mess up the sizing process and length measurements. The slightly bent ones may flatten out in sizing but some are just ruined.
The price you pay for a semi-auto I guess. :usa:
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10 years 20 hours ago #37359

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Replied by Siscowet on topic AR10T case rim strike - issue?

I went out today to break in the barrel on the new AR10T carbine. As construction was going on at the range, I couldn't sight in, but was able to shoot the break in process at one of the berms. The point I am making is that my brass had exactly the same kind of marks as Blazermark had on his, and the rim was beat up as well. As my full length gas system on my other AR10 doesn't cause this, I am wondering if it is due to the shorter carbine length gas system having a more violent ejection pattern. Function was flawless, recoil is definitely more than with the rifle version, but manageable. I was shooting M118LR and FGMM 175 SMK's as that will be what I will be initially feeding this one, so I decided to use them for break in.
9 years 11 months ago #38065

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