9mm AR occasional FTE?

BenL · Aug 8, 2016

I put 350 rounds of Blazer brass case 115gr ammo through a new Stag 9L, and was getting just enough FTE's to be annoying (4X in 350 rounds).

After some quick Googlin', it appears the most common recommendation is to adjust the ejector. I don't think that's it, though. It's happening so infrequently, I suspect that perhaps it's just the cheap ammo is too under-powered. Could that cause FTE's? The FTE is the spent case is jammed into the receiver port (another round was picked up from the mag.) I did change a few things about the gun, but don't think they have anything to do with it.

What say the experts?

photoracer · Aug 8, 2016

While underpowered ammo could cause that I doubt the ammo you are using is in that category. Mine handles everything from CCI and Federal, and the only thing I can get a definite FTE on is Remington UMC 250 rd. yellow box ammo.

j_h_smith · Aug 8, 2016

I would try a heavier bullet. Try 147 gr ammo and see what happens. Many 9mm rifles don't like the 115 gr. Secondly, make sure the rifle is lubricated with quality lube. Another thing to consider is how many rounds have you ran through this rifle. If this was your first time out with it, you may want to put a few more round (650+) through it to make sure everything is broken in properly. Technically speaking, how heavy is your buffer? Are you running a ramped bolt carrier? If not, do you have a 9mm hammer installed? Personally I run both the ramped bolt AND the 9mm hammer.

Go from the cheapest fix to the most expensive fix. Lube that sucker really well. Try a heavier grain bullet 124 or 147 first. I've had trouble trying to get the 115 to run consistently. Then start looking at parts replacement.

YMMV

BenL · Aug 8, 2016

I cleaned it and lubed the hell out of it with Slip 2000 EWL; the spring and buffer are whatever came in the gun.

I did switch out the FCG to a Giessele SSA-E. Could that be causing it? The factory FCG just looked like a milspec group. (the bolt carrier is ramped.)

I'll pick up some 124gr and 147gr and see how that goes. Like I said, the cheap 115gr *almost* works (a few failures in 350 rounds.) Maybe give it some more time to break in, too. If I can just reload a little hot, I may just do that.

I was surprised at how filthy the gun (and I) got after only 350 rounds; I've put more than 1000 rounds through a DI 5.56 that wasn't that dirty.

This is only a game gun (USPSA PCC), but it still needs to be reliable.

BenL · Aug 8, 2016

photoracer said:
While underpowered ammo could cause that I doubt the ammo you are using is in that category. Mine handles everything from CCI and Federal, and the only thing I can get a definite FTE on is Remington UMC 250 rd. yellow box ammo.

Do you have an aftermarket trigger in yours? What's your go-to ammo?

jimbobborg · Aug 8, 2016

Some of the Geissele triggers are specifically noted to not work well with 9mm ARs.

BenL · Aug 8, 2016

jimbobborg said:
Some of the Geissele triggers are specifically noted to not work well with 9mm ARs.

Of course they're not...

I started off trying to use a 3 Gun style trigger, but neither the Geissele nor Wilson Combat 3G trigger worked (I tried both.)

j_h_smith · Aug 8, 2016

BenL said:
I cleaned it and lubed the hell out of it with Slip 2000 EWL; the spring and buffer are whatever came in the gun.

I did switch out the FCG to a Giessele SSA-E. Could that be causing it? The factory FCG just looked like a milspec group. (the bolt carrier is ramped.)

I'll pick up some 124gr and 147gr and see how that goes. Like I said, the cheap 115gr *almost* works (a few failures in 350 rounds.) Maybe give it some more time to break in, too. If I can just reload a little hot, I may just do that.

I was surprised at how filthy the gun (and I) got after only 350 rounds; I've put more than 1000 rounds through a DI 5.56 that wasn't that dirty.

This is only a game gun (USPSA PCC), but it still needs to be reliable.

From what I've heard, others are using that trigger group without issue, so I don't think that's it. See what the other ammo will do for ya. I don't think you need to run hot loads.

This 9mm AR rifles are blowback design, so yes, they get filthy. That's just the nature of the beast.

Good luck and let us know things are progressing.

clandestine · Aug 8, 2016

SSA-E works with a 9mm AR. Its hard to say why its doing that, but its possible the extractor needs more or less tension. They tension like a 1911 extractor.

The ejector may still need to be adjusted as well.

Its also possibile that the action spring or buffer is wrong.

Are you using C Products 9mm mags, if not what brand? 9mm AR mags can be flaky.

BenL · Aug 8, 2016

clandestine said:
SSA-E works with a 9mm AR. Its hard to say why its doing that, but its possible the extractor needs more or less tension. They tension like a 1911 extractor.

The ejector may still need to be adjusted as well.

Its also possibile that the action spring or buffer is wrong.

Are you using C Products 9mm mags, if not what brand? 9mm AR mags can be flaky.

Thanks, Chad. I'm using factory Stag mags (like Uzis or Colts.)

I tried not to change too much that would effect reliability (the FCG were the only internals I changed.)

Do you think this is something that could work itself out after a few thousand rounds?

photoracer · Aug 8, 2016

It's got a Timney Competition Trigger. Runs good on CCI Blazer or Fed Redbox brass or aluminum case.

Sent from my XT1064 using Tapatalk

sailskidrive · Aug 8, 2016

I have that trigger in my 9mm and it runs just fine. The only issue I ran into is that mine prefers the round nosed bullet types; the blunt/slightly flat nose bullets don't always feed properly. I have a CMMG lower and use Metal Form mags bought from Precision Firearms.

Yes... It is a very filthy little beast... I've never cleaned it and it's pretty caked up with carbon. I just add more lube.

davsco · Aug 8, 2016

go get and try some glock mags.

just kidding.

last two matches i used 115g wwb with zero issues. that's what my sti steelmaster is spec'd for so i loaded up with two cases. i asked the jp guy what they recommended and he said to just buy the cheapest 9mm ammo you can.

anyways hope you get it working. unless you're shooting the same match with me, then i hope it pukes on every stage! ahahaha

BenL · Aug 9, 2016

davsco said:
go get and try some glock mags.

just kidding.

last two matches i used 115g wwb with zero issues. that's what my sti steelmaster is spec'd for so i loaded up with two cases. i asked the jp guy what they recommended and he said to just buy the cheapest 9mm ammo you can.

anyways hope you get it working. unless you're shooting the same match with me, then i hope it pukes on every stage! ahahaha

Very funny.

Is it common to see PCC with issues at matches? Are they known to be finicky?

jimbobborg · Aug 9, 2016

BenL said:
Very funny.

Is it common to see PCC with issues at matches? Are they known to be finicky?

I hope not. I'm buying the rest of the parts online tomorrow.

davsco · Aug 9, 2016

BenL said:
Very funny.

Is it common to see PCC with issues at matches? Are they known to be finicky?

not sure i've seen enough PCC's at matches to say whether anything is 'common' or not.

had issues with mine the first two times out, something must have been under the trigger as it would occasionally freeze for lack of a better word. i sprayed the heck out of the trigger channel with CLP then blew the heck out of it with an air hose then lubed it back up and it's been perfect since (so two matches), and even got me first overall at the gravitas steel match (blind squirrel found an acorn i guess).

my bil got a wilson that has occasional jams; he's sending it back to them.

i've seen a couple of others that had zero issues during the couple of matches i've done.

clandestine · Aug 10, 2016

BenL said:
Thanks, Chad. I'm using factory Stag mags (like Uzis or Colts.)

I tried not to change too much that would effect reliability (the FCG were the only internals I changed.)

Do you think this is something that could work itself out after a few thousand rounds?

Its hard to say if it will work itself out. Ammo may be the cause or you may need a lighter spring and or buffer. Its possible that its underbuffered too. If sona tubb spring and heavy buffer are the ticket.

Boss94 · Aug 11, 2016

Sounds like the ejector may need to come up just a bit closer to the bolt carrier.

BenL · Aug 22, 2016

UPDATE

Without cleaning the gun (I only wanted to change one veritable) I shot 150 rounds of 115 gr Federal red box and 100 rounds of 115 gr Winchester white box; not a single FTE.

So, either it was the Blazer ammo or the issue worked itself out. Either way, I'll take the "win". Looking forward to my first PCC USPSA match (Sept. 10th.) I think I'm taking off the irons and switching to an Eotech, too.

j_h_smith · Aug 22, 2016

BenL said:
Without cleaning the gun (I only wanted to change one veritable) I shot 150 rounds of 115 gr Federal red box and 100 rounds of 115 gr Winchester white box; not a single FTE.

So, either it was the Blazer ammo or the issue worked itself out. Either way, I'll take the "win".

They need some time for the parts to wear in properly. Regardless, I'm glad it's working for you now.

Those 9mm AR rifles are a hoot to shoot. I love em...

9mm AR occasional FTE?

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