Intermittent anemic ejection

[BoyGlock]

This happened before twice already, after a few hndred rounds of weak ejection it would be back to the usual positively throwing empties at least 5' away. This would last for 3-4t rounds then suddenly empties would just dribble out to a foot away. Its so weak that very few times it stovepipes. Then it would repeat the cycle again. Im on its third time now and Im baffled as to its cause. Its an Sti custom, aftec extractor, 8# rec. spring, 17# main spring, 38S/SC at 170pf. I suspect something is binding at the start of the slide retraction then frees the slide to move rearward but the momentum was already reduced that the slide weakly ejects the empties without much force. This happens even if the gun is clean. Ive visually inspected the innards of the gun everytime this happens and found nothing unusual. What baffles me is that it would suddenly revert to its previous condition as if nothing happened.

Can anybody pls. suggest possible causes to this?

Thanks.

[Hi-Power Jack]

Are you using a rubber recoil buffer?

[BoyGlock]

Yes ever since it was built more than a year ago.

[Arlin]

Sounds like an intermittent low powder charge. This has happened to me before. The only other thing that may be happening is your thumb may be riding the slide.

Arlin

[Aircooled6racer]

Hello: Take the buffer out and throw it away. Then try it again. Take your extractor out and clean it and the tunnel. Check your ejector to see if the end is broken. Check to see if you have the recoil spring in correctly. Thanks, Eric

[Sarge]

Upright scope mount? My guess is the ejector somehow got "out of tune" and is ejecting into the scope mount. My gun is a 9mm but it ejected fine until I changed the slide. After that it never ran the same. It stovepiped often. A buddy actually saw it happen and I tore the gun down and cleaned and inspected and found little dings on the edge and bottom of the mount and scope. Worth looking at at least. It's not like there will be huge chunks missing out of the mount. The marks on mine were practically invisible until I started looking for them.

I could have probably gotten it retuned but the 90 degree mount is working very well for me. No more issues!

[BoyGlock]

Thanks guys for all your inputs.

1. Intermittent powder charge - seemed unlikely. I reload my ammo and shoot them in my 2 38 open guns. The recoil is consistent and doesnt exhibit said problem on the other pistol

2. Without rec. buffer - I will try this next range session.

3. Extractor and ejector condition - both are in good cond. and are clean. No binding of ejector to the slide.

4. Rec. spring - correct position.

5. Upright scope - yes. There are dings in the underside of the mount but when ejection is weak the empties hardly lift to reach the mount.

6. Finger rubbing the slide - I have small hands so its unlikely.

What all these things make is unreliable ejection/extraction until you fixed the parts. But this gun will just weakly eject for hundreds of rounds then just revert to its usual reliable positive ejection without me changing anything. Its as if its clearance on some parts suddenly goes out of specs then causes the slide/barrel/frame to bind a bit for hundreds successive rounds then untangles itself and reverts back to its usual reliable self.

As said, this is the third time. In the first 2 I just let it be and just dissapeared. The only difference now is it stovepipes once every hundred or so in my estimate so I cannot just ignore it now.

Again thanks for your time and knowledge. Pls. Keep it coming.

[peterthefish]

Thanks guys for all your inputs.

5. Upright scope - yes. There are dings in the underside of the mount but when ejection is weak the empties hardly lift to reach the mount.

Are you using a camera to verify? At speed it may hit the mount, bounce down, and appear to be weak ejection.

If none of the above, I think someone is oiling your gun when you're not paying attention.

[BoyGlock]

Thanks guys for all your inputs.

5. Upright scope - yes. There are dings in the underside of the mount but when ejection is weak the empties hardly lift to reach the mount.

Are you using a camera to verify? At speed it may hit the mount, bounce down, and appear to be weak ejection.

If none of the above, I think someone is oiling your gun when you're not paying attention.

No camera. And nobody touches my guns without my knowledge ? But can it account for successive weak ejection for hundreds of rounds? Thanks for the input.

[peterthefish]

Could if your extractor is gunked up. Have you pulled it and checked the springs and cups? Maybe replace the springs?

[BoyGlock]

Could if your extractor is gunked up. Have you pulled it and checked the springs and cups? Maybe replace the springs?

Extractor and tunnel are clean and springs and cup are good. But I will take a closer look at it again asap. Still it cannot account for the sudden appearance and disappearance of the prob without doing anything in the gun and ammo.

Thanks again.

[BoyGlock]

I think it has less to do with extractor and ejector as it behaves the same on S and SC brass. Im using an aftec S on both.

[Siphon Odesse]

I have been experiencing some of the same, albeit with less of the cyclic appearance you describe. To add to the confusion, I only experience stovepipes with one specific magazine! I too took the gun to pieces, un-gunked aftec and its tunnel, etc. etc. New recoil spring, SV-ish gun, bells, whistles and whatnot. Cleaned the magazine, checked mag-lips for dents etc etc.
*sigh*

Siphon

[Doug S]

Since we are throwing out possible causes, I'll tell you what mine did. I installed a DAA sight mount on my STI, it had a Serendipity previously. So it went from a 2 sided mount to a 1 sided. Then I installed an RHT thumb rest. This rest used 2 of the mounting holes, so I had the front hole of the sight mount that was tapered and the screw centered the mount on THIS hole only. There was just enough room on the other 2 holes to allow my sight mount to creep up on the back side and rub against the bottom of the mount. This was just enough to slow the slide down and not eject correctly. I would shoot a stage and the gun would work great then the next stage it would be a really expensive single shot!

I took the RHT thumb rest off and put the DAA thumb rest back on, the problem went away. I had my gun apart at least 10 times before I removed the mount and found the problem. Good side was that I polished ALL of the internals, one at a time, to try and fix the issue. Resulted in a very smooth running gun.

There wasn't anything wrong with the DAA mount or the RHT thumb rest, just the loose nut behind the gun!

Remove your mount when the gun gets sluggish, then shoot it without the mount. Might help, might not. Just my .02 worth.

Good luck.

Doug

[BoyGlock]

To update everyone:

I tried your suggestions with little success.

The night before a match last Sun. out of desperation, I replaced the front spring of the Aftec. Check the tension and hoped/thought it was good to go without any live fire test.

The morning of the match I had jams in 2 out of my first 3 stages. The jams were ftf, an indication of too much tension. I survived the 4th stage before noon break. At the break, again out of desperation, I stripped the gun in the safety area and replaced the front spring with the old one I replaced the night before. I also noticed that gunk accumulated in its hook which I thought was unusual as I had only shot around 75 rnds at most. I cleaned it and reassembled the gun. Shot all remaining three long stages with nary a hiccup! I also noticed the ejection was very positive all through out the stages!

This afternoon I went to the range and practiced and tested it further. The anemic ejection was completely gone! Im puzzled for the nth time! Virtually I had the same gun with the same old parts but its back to its usual reliable self as if nothing happened.

Thanks for everyone's ideas and inputs. Hope the gun will remain as is till kingdom come ?

Edited May 6, 2015 by BoyGlock