My 9mm AR was filthy

outrider58 · Sep 11, 2017

Well, I just went through all the brass from the other day's shoot. Close to 200 pcs. Of the 11 PPU cases that were shot that day, seven showed similar but not a severe signs of swelling. No signs of over pressure. Not a single case to the exception of the PPUs showed any out of the ordinary signs. I'm thinking bad brass at this point. BTW, I cleaned all the brass in order to get a good look at them. I cleaned my gun as well. It was not that dirty at all. For the round count, I think it was cleaner than my two DI SBRs that I also run almost exclusively suppressed. I welcome your thoughts, as always. :shrug:

j_h_smith · Sep 11, 2017

I think you're going to need another outing without shooting any PPU brass. I think you'll be okay. I didn't know this about PPU ammo/brass and I'm glad I never bought any. I will have to check my range pickup brass and make sure they go into the scrap pile.

Good Luck!

bfoosh006 · Sep 15, 2017

outrider58 said:
KAK standard configurable buffer (with 3 tungsten weights) and Tubb's 308 flat wire spring.

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WOW !!!

I am glad you didn't get a blowout !

outrider58 · Sep 16, 2017

bfoosh006 said:
WOW !!!

I am glad you didn't get a blowout !

Thanks! I did change buffers to a Spikes ST-9X heavy buffer. I should be back at the range soon. First, I still need to go over all my reloads, at least 2K, and pull all the PPU out. Fortunately there aren't very many.

bfoosh006 · Sep 16, 2017

outrider58 said:
Thanks! I did change buffers to a Spikes ST-9X heavy buffer. I should be back at the range soon. First, I still need to go over all my reloads, at least 2K, and pull all the PPU out. Fortunately there aren't very many.

How brisk was your firing rate ?

And did you check any of the other fired cases for signs of "less then fully seated BCG firing " ( for lack of a better phrase )

I can't say I saw any bulged cases in my test firing of all the 9MM ammo out there... I wonder if you did get a bad batch of PPU brass.

bfoosh006 · Sep 16, 2017

Huh.... I just reviewed my 129 different 9MM chrono tests... and PPU did "setback" .... repeatedly... along with Fed. 115gr Aluminum cased, Colt 124gr SCHP, Fed. Syntech 115gr, and the SIG V-Crown ( HP was just to wide for reliable feeding ) and Remington 124gr GS.

Everything else fired various brands and weights was GTG.

PPU setback

outrider58 · Sep 16, 2017

bfoosh006 said:
How brisk was your firing rate ?

And did you check any of the other fired cases for signs of "less then fully seated BCG firing " ( for lack of a better phrase )

I can't say I saw any bulged cases in my test firing of all the 9MM ammo out there... I wonder if you did get a bad batch of PPU brass.

Rate of fire is about 1round every 2 seconds @100yds ans 1 round every 1 second @ 50yds. I transition between both ranges while running a 32 round mag. 5-10 rounds on each target, back and forth until mag is empty.

Not sure what you meant in the bolded sentence.

Below is a pic I just took of fired brass from that day. The one on the right is the worst of the PPU. To the naked eye, there is a slightly discernible difference in primer strike and/or 'flow' on the one on the right(PPU). It isn't alarmingly bad though. The primers are Winchester Small Pistol. If they're anything like they're SRPs, they are relatively soft as primer cups go.

bfoosh006 · Sep 16, 2017

Just trying to describe your bugled cases issue.

Still kind of speechless.

inkd · Sep 16, 2017

outrider58 said:
Not sure what you meant in the bolded sentence.

I think he may have meant "out of battery firing"?

outrider58 · Sep 16, 2017

inkd said:
I think he may have meant "out of battery firing"?

Ok. I'm still not convinced that was the case. 'Hiyeva', I did put a heavier buffer in the gun and went through some 2000 rounds of reloads and removed 20 or so rounds of PPU brass. That wasn't much fun, but out of the 1k rounds I've put through that gun so far, the hand full of PPUs were the only hiccup. My fingers are crossed.

j_h_smith · Sep 16, 2017

outrider58 said:
Ok. I'm still not convinced that was the case. 'Hiyeva', I did put a heavier buffer in the gun and went through some 2000 rounds of reloads and removed 20 or so rounds of PPU brass. That wasn't much fun, but out of the 1k rounds I've put through that gun so far, the hand full of PPUs were the only hiccup. My fingers are crossed.

That would be nice if that was 90% of your problem. I would have never thought the PPU brass would cause this kinda trouble.

Good Luck!

outrider58 · Sep 16, 2017

j_h_smith said:
That would be nice if that was 90% of your problem. I would have never thought the PPU brass would cause this kinda trouble.

Good Luck!

Thanks Jim. I'm sure, with the help of the good folks here, we'll get it worked out. :thumbsup:

jimbobborg · Sep 17, 2017

I'm throwing in the towel and am seeking professional help on mine. I'm still getting random FTEs and it's killing my times.

outrider58 · Sep 17, 2017

jimbobborg said:
I'm throwing in the towel and am seeking professional help on mine. I'm still getting random FTEs and it's killing my times.

Have you been using the same barrel the whole time? Have you tried other(people's) uppers?

j_h_smith · Sep 17, 2017

jimbobborg said:
I'm throwing in the towel and am seeking professional help on mine. I'm still getting random FTEs and it's killing my times.

Is the fired case staying in the chamber or is it starting to eject but not making it out of the receiver? Do your cases have extractor marks/heavily ripped up case where the extractor is pulling through the case and the case not moving? Are you getting a round to feed unto your case that failed to eject which causes a jam.

I'm wondering if you don't have a tight chamber.

There are only so many things that can cause your problem. Are you experiencing these FTE with factory ammo and/or reloads?

Have you tried another bolt?

There's a lot of questions I threw at you and I apologize if you've already answered these.

It's a little confusing because I think there's at least 2 of you having issues and I can't remember who I've asked questions of.

Keep the faith. You'll figure it out.

First step would be to borrow another bolt and see if the problems are still there.

Second, find someone with headspacing gauges and check out your barrel.

I did forget to ask you, what type of hammer do you have in the lower?

If all else fails, I have an almost new bolt and I can remove a hammer from one of my rifles to send to you. I'd be very interested in finding out if either of these 2 things can help.

jimbobborg · Sep 17, 2017

When I shot this last match, I swapped out the old BCG of unknown origin with a brand new CMMG 9mm BCG. The brass ends up jammed into the top of the receiver because the next round is being shoved into the chamber. The mouth is facing out. I have to break out the multitool to get the brass out. The trigger is a POF drop in. The buffer is a CMMG 9mm buffer with a standard carbine spring. The lower and upper are dedicated 9mm from CMMG. I've used various 115gr brass, 115gr steel cased, and my reloads. All of this was working great until a few days before I posted this. Prior to that, the only change I made was swapping out a cheap holographic optic for an Eotech. I'd rather keep the Eotech as it doesn't wash out during the middle of the day versus the cheap optic.

j_h_smith · Sep 17, 2017

Do you know anyone with gauges that you could check the chamber? Can you tell if somehow you have a burr in the chamber? Run a Q-Tip around the chamber and see if the Q-Tip comes out smooth or frazzled due to a burr.

Good Luck!

outrider58 · Sep 17, 2017

Sounds to me like an action problem. Try a different spring?

jimbobborg · Sep 18, 2017

outrider58 said:
Sounds to me like an action problem. Try a different spring?

Lighter or heavier?

outrider58 · Sep 18, 2017

jimbobborg said:
Lighter or heavier?

Definitely heavier.

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My 9mm AR was filthy

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