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Is my lower causing my brass to look like this?

J

JRBullock1987

Private
Minuteman
Sep 8, 2023
28
6
Washington
I have a 20" woa spr build with an aero precision upper jp fmos bolt. Giessele rail. Oss 7.62 hq qd suppressor. 5d tactical 80% lower and a giessele lpk. I've built my upper twice with 2 different upper receivers. Both aero uppers. And my brass still looks like this with standard milspec federal xm195 ammo. Everything is tightened to spec and no matter what I do my brass still looks like this. The only thing I can think of is its the lower but everything looks normal. Am I missing something? I reload but its hard to know when im getting pressure issues when milspec ammo flattens my primers and shows ejector swipe.
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Agree primers don't look flat. Ejector swipes don't look like metal is extruded then sheared. Where is it ejecting? It looks to me like the marks you get from over gassing.
 
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JRBullock1987 said:
What's causing the wear on the face around the rim of the primer pocket akd the ejector swipe? Or is that not what ejector swipe looks like? I'm super new to reloading and inspecting brass so idk what I'm looking for
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They look like normal ejector marks to me especially if the brass is being flung forward (sign of over gassed). Not necessarily a bad thing depending on the purpose of the rifle.
 
How far are you pushing the shoulders back? Looks like you might have over-sized a touch, since the ejection is fine, the primers are fine, and it's just an ejector mark. How fast are they running?
 
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JRBullock1987 said:
About 4 thou but these are federal xm195. I didn't reload these
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I misunderstood. I thought they were reloads.

Irregardless, I don't think those marks are a) something to worry about or 2. caused by the lower.

You can still check how far the headspace grew unfired->fired, if its growing a lot it can cause those faint ejector marks even at normal pressures.
 
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Over gassed or under buffered, I see you mention a suppressor in that spec list were you shooting those behind the supressor? If so, welcome to the game, suppressed ar 10's are another world altogether. Does it have an adjustable gas block? I had to go to a JP VMOS with full tungstens weights to operate well with a suppressor.
 
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Yeah, nothing exciting about those primers or little smears.
JRBullock1987 said:
Lol woops thanks. Brain fart. You know you've got a shite memory when you just opened a box and you miss name it lol
Click to expand...
Don't feel bad. Guys post pics of case heads that say Creedmoor right on them and still manage to write "Creedmore" all the time.
 
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xm193 has always been on the hot side for me. Doesn't look too bad but good that your paying attention.
 
I agree. Just looks like a little witness mark from the ejector. Has to be more pronounced or taken in combination with other signs before I'd worry too much

You might like this video. Covers reading brass pretty well




Screenshot_20240418_210146_Google.jpg


extruded.jpg
 
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