New 9mm build, lots of FTEs. - Page 1

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[ARCHIVED THREAD] - New 9mm build, lots of FTEs.

Posted: 4/3/2017 11:20:27 PM EDT

I took my new build out over the weekend and was getting an FTE almost every other round. It's an NFA lower and I'm using a Spikes ST-9X heavy buffer. Had the same issue with different mags. I was shooting 115 ammo, so that might be part of it. Do I need to use a lighter buffer? Or is this an extractor issue? Also just testing it without firing, it does not kick out the rounds when I manually cycle it.

Here's a pic of an FTE. FTE

And a pic of my CMMG bolt face: Bolt Face

Posted: 4/4/2017 12:03:05 AM EDT

[#1]

I would start with a standard buffer and verify bolt isn't dragging your hammer/trigger.

.

Posted: 4/4/2017 12:06:46 AM EDT

[#2]

I think it's the heavy buffer

Posted: 4/4/2017 12:08:46 AM EDT

[#3]

Quote History

Quoted:
I would start with a standard buffer and verify bolt isn't dragging your hammer/trigger.

.

View Quote

I'll try that next. How can I tell if the bolt is dragging? It doesn't feel like it's catching on anything when I charge it and it doesn't feel like I'm forcing it either.

Posted: 4/4/2017 12:34:06 AM EDT

[#4]

If the ejector is slightly out of position it will change the angle of ejection enough for the case to hit the inside of the receiver instead of going out the port. So sometimes it just needs a little tweak.

Posted: 4/4/2017 1:06:31 AM EDT

[#5]

Quote History

Quoted:
If the ejector is slightly out of position it will change the angle of ejection enough for the case to hit the inside of the receiver instead of going out the port. So sometimes it just needs a little tweak.

View Quote

This. Make sure your ejector is riding right up against the inside of the bolt without touching it.

Posted: 4/5/2017 12:05:42 AM EDT

[#6]

Quote History

Quoted:

This. Make sure your ejector is riding right up against the inside of the bolt without touching it.

View Quote

Does anyone have a picture of what it should look like?

I tried to take some pics of mine, can anyone tell if that looks like it needs adjusted?

Pic 1

Pic 2

Pic 3

Pic 4

If it's too close to the bolt face, do I just pry it out little by little until it cycles correctly?

Thanks again for the help.

Posted: 4/5/2017 4:34:27 AM EDT

[#7]

that's the extractor on the bolt. the ejector is on the lower

Posted: 4/5/2017 8:31:34 AM EDT

[#8]

the ejector in my NFA lower slightly drags on a PSA bolt, but not the NFA bolt... allow the bolt to slowly move forward, and you can probably feel a slight drag as the bolt passes the ejector...

most likely the cause is too heavy a buffer....borrow an H2 from someone and see if the 4.2oz works better with the lighter bullets....I think that something between 20 -22 oz total for buffer and bolt should get you in the ball park

with the bolt out, see that a fired case is securely held by the extractor

Posted: 4/6/2017 1:18:02 AM EDT

[#9]

Quote History

Quoted:
the ejector in my NFA lower slightly drags on a PSA bolt, but not the NFA bolt... allow the bolt to slowly move forward, and you can probably feel a slight drag as the bolt passes the ejector...

most likely the cause is too heavy a buffer....borrow an H2 from someone and see if the 4.2oz works better with the lighter bullets....I think that something between 20 -22 oz total for buffer and bolt should get you in the ball park

with the bolt out, see that a fired case is securely held by the extractor

View Quote

Ok, I think you're right. Moving my bolt slowly over it, I can definitely feel it drag. It's not major, but now that I'm looking for it, it is noticeable as soon as the bolt goes over the extractor and there is some slight wear showing up on one of the extractor edges.

I have a spare standard buffer laying around, would that work? Or do I need to try and shave down the NFA extractor?

Thanks again for the help on this.

Posted: 4/7/2017 4:29:11 AM EDT

[#10]

Quote History

Quoted:

Ok, I think you're right. Moving my bolt slowly over it, I can definitely feel it drag. It's not major, but now that I'm looking for it, it is noticeable as soon as the bolt goes over the extractor and there is some slight wear showing up on one of the extractor edges.

I have a spare standard buffer laying around, would that work? Or do I need to try and shave down the NFA extractor?

Thanks again for the help on this.

View Quote

Try to move the ejector slightly so it no longer contacts the bolt, allowing the bolt to travel smoothly.

You can use a sharpie to mark the ejector, run the bolt over it, and then use that to determine how much, and what direction to move it.

Moving it over ever so slightly isn't hard...it will require finesse as it only needs the slightest tap with a very small hammer.

I've done before, and it does work just fine. You'll find other threads describing the same process in more detail.

I used a cheap usb "endoscope" camera off amazon, then just inserted into the barrel towards the bolt to see what was happening as I cycled the bolt back and forth.
Saw the ejector rubbing, tap-tap, the gun runs great.

.

Posted: 4/7/2017 8:55:14 AM EDT

[#11]

I don't think a few test shots with a standard carbine buffer would hurt... some friends have chewed up the elastomer with sustained use....I shoot a heavier hand loaded bullet for USPSA PCC with about a 148 power factor and use a rifle stock and tube so I was able to experiment with different weight buffers...., so am not that familiar with the lighter factory stuff...I built a 9oz buffer for some experimentation, and it battered the bolt face barrel breech area when it slammed home, so went back to a 5.2oz rifle buffer and standard rifle spring ...my 10.3 SBR works well with an H2 carbine buffer and PSA bolt.... good luck

Posted: 4/7/2017 10:52:31 PM EDT

[#12]

go to advance auto parts, get a cheap set of feeler gauges and shim the ejector over with them......please post a picture of the ejector from the side.......doubt seriously it is the buffer......

Posted: 4/7/2017 11:00:41 PM EDT

[#13]

OP would be better off if he'd stop confusing the extractor and ejector.

Posted: 4/8/2017 12:26:15 AM EDT

[#14]

Quote History

Quoted:
go to advance auto parts, get a cheap set of feeler gauges and shim the ejector over with them......please post a picture of the ejector from the side.......doubt seriously it is the buffer......

View Quote

I think you're right, it seems like the bolt carrier is riding the ejector. I'm not sure if you can tell from the pics below, but there is a pretty defined wear mark on the one side. I'm wondering if I should try a different bolt carrier.

Ejector 1

Ejector 2

Posted: 4/23/2017 9:20:26 AM EDT

[#15]

I had the exact same problem with a PSA 9mm build. The gun would leave spent cases in the action. The ones that did eject only went a foot or so. I bent the ejector (in the lower) inward towards the center of the bolt and solved the problem completely. Cases are now thrown 20 feet from the gun!

My buddy had the same problem and bending the ejector inward cured his too.

[ARCHIVED THREAD] - New 9mm build, lots of FTEs.

AR-15 » Rimfire and Pistol Calibers

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