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Feeding issues revisited


Sarge

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This didn't get traction last go around so I'd like to give it another try.

Two year old open gun. Ran 100% the first year.

Second year developed an issue with apparent nose dives where gun stops running and I find the top round wedged against the front of the mag.

Sounds simple right? But wait here are all the buts:

- happens with 4 different bullets.

- happens with oals from 1.10 to 1.17

- happened with steel grip, happens with new polymer grip.

- STI mags with spacers that have been tuned, retuned and triple checked.

- happens with clean or dirty gun

- mags AND ALL mentioned ammo runs flawless in my other gun as well as another open test gun.

- will run 500 perfect rounds from all mags during test fire. Slow , fast mag dumps etc- perfect.

- in a match The gun jams right from the start taking 3 mags to finish a stage.

- symptoms are the same for hot or cold weather

- last time I asked the forum I got "go with MBX mags they fix all problems. Or get SV mags! If there were ANY signs of problems in other guns I would get new mags tomorrow but the fact that all 8 mags run perfect in every other gun so far screams "gun problem" not mag problem.

I also refuse to believe I need different mags for just one gun. Granted I haven't tested with any other mags but that's because every time I have a problem I go run a few hundred rounds through the gun off the clock and it's just as reliable as my other gun.

I actually wondered today if it's caused by wet tumbling my brass? That is the only thing that's changed since the problem started. The rounds are tarnished and just are not as slick as they used to be.

Could there be a burr on the bottom of the slide ?

When I look at both guns they appear identical in ramp set up , polish, angle etc but like I said it's happening in the mag because I can drop the mag and the round stays jammed.

Any thoughts or experiences would be appreciated as it is about to drive me nuts.

Thanks in advance for the wisdom as long as it's not, bend the spring, change the springs etc because that's all been done with no effect

Edited by Sarge
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Now that you posted this i started thinking. My problem started after running my nickel 38 super brass in walnut media in my vibrator. Usually run it for 4 or 5 hours with a little liquid polish. Comes out shiny and slick. Shut it off and forgot to dump it. When I did next day noticed some tarnish maybe rougher than it should be. Could be too rough or not as slick as normal? Coincidence? Could be our problem.

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Hello: So what has changed from test fire to match fire? Two different grips and the same problem during a match. Different mags and the same problem during a match. So what are you doing during a match that is different. Pro Grip on your hands? Dirty mags? Need more oil on the pistol? Thumb riding the slide or activating slide stop? I would take the pistol all apart and look at everything with a magnifying glass. Something has changed since it ran 100% before. Hope this helps. Thanks, Eric

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Hello: So what has changed from test fire to match fire? Two different grips and the same problem during a match. Different mags and the same problem during a match. So what are you doing during a match that is different. Pro Grip on your hands? Dirty mags? Need more oil on the pistol? Thumb riding the slide or activating slide stop? I would take the pistol all apart and look at everything with a magnifying glass. Something has changed since it ran 100% before. Hope this helps. Thanks, Eric

I hear ya! Something has changed without a doubt because it don't work! lol

Gun was bone dry in practice and it ran great. Then I drenched it in oil and it ran great. Stopped shooting it and took it to the match as is and jammed with 3 mags on the first stage.

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ok here's my wild guess, replace the firing pin spring , pin bouncing as slide picks up round and catching top of brass causing round to dive into feed ramp or mag

sounds crazy but give it a try

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ok here's my wild guess, replace the firing pin spring , pin bouncing as slide picks up round and catching top of brass causing round to dive into feed ramp or mag

sounds crazy but give it a try

At this point nothing would sound crazy! Thanks I'll check it out
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Since it's a match problem I'm guessing no pictures. Can you stage the malfunction and photograph it?

Tell me if I have the problem right. Is the problem round drug forward by the round above it getting chambered and then upon firing the forward drug round, now the one being fed, is pinned in the magazine?

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Tell me if I have the problem right. Is the problem round drug forward by the round above it getting chambered and then upon firing the forward drug round, now the one being fed, is pinned in the magazine?

This is my assumption because I have loaded them real long and real short, new mag springs (twice since I thought they might be defective lol), so they should be popping up when presented for chamfering. The gun feels exactly like a 1911 locking back on an empty mag when it occurs, just the round is smashed against the front of the mag. Next time it happens I'll post a pic because I can actually remove the mag and the round doesn't budge.

Edited to add, JHP, IFP, BBI AND EXTREME HP. THE EXTREMES are very round though so I am not inclined to blame bullet shape. Besides the jam just seems to be more related to something jamming the mag as opposed to a true misfeed

Edited by Sarge
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More likely to happen when mag is full or does it happen any time?

Going on the ran perfect for a year, now won't path makes me think wear. Maybe wear on the magazine release, mag catch cutout in the magazine, or inside of grip wear/dimensions. Could you try inducing the malfunction by pulling the bottom of the mag fore, aft, and side to side while shooting? Could that be enough to screw up the feeding geometry?

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Sarge,

I'm trying to picture what you mean by the "top round wedged against the front of the mag", but you say you can remove the mag and the round doesn't budge? Do you mean the round is jammed between the breach face and the ramp?

I assume you've already checked to make sure you have clearance under the ejector and that the bottom edge of the breach face/slide is slightly beveled/smooth. It doesn't sound like an ejector issue, but if you've got too much tension, it could be contributing to your feeding problem. Standard ejector or Aftec?

I would also polish up the ramp with a small felt wheel and some Flitz making sure the rotation of the wheel is turning in the direction of feeding. Having a mirror polish on the ramp should help you see if there are any bumps or imperfections that may be causing issues.

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When you say you changed the springs, if you mean the springs in your mags - I'd

try changing the springs (all of them) in your GUN.

Once I got my mags working, my TruBor ran great for 5,000 rounds (flawlessly),

until it was time to change the springs in my gun - now it's running another

5,000 rounds without a hiccup :)

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You might be able to cure it by using a true round nose bullet (Jacketed preferred over plated) as the tip of the bullet might be above the top edge of the magazine even when it nosedives.

the nosedive problem is not helped by the fact that the 9mm luger has a tapered case, but nosedive can be less problematic in a double column magazine if well designed, whereas a single column magazine experiences nosedive as a natural event.

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My .02....gun runs flawlessly doing a mag dump, not during a match, or runs flawlessy slow fire, not during a match...IMO, could only be one of two things...your grip has changed (the way you grip the pistol during a match), or that top round is dragging on the bottom side of the slide, pulling it forward. You can polish the under side of the slide (make sure there are no burrs on the bottom edge of the breach face) or change your grip...I was having a very similar problem with my Shadow...polishing the under side of th3 breach face and removing the burrs (slight bevel to the bottom of the breach face) cured all of those issues..

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You might be able to cure it by using a true round nose bullet (Jacketed preferred over plated) as the tip of the bullet might be above the top edge of the magazine even when it nosedives.

the nosedive problem is not helped by the fact that the 9mm luger has a tapered case, but nosedive can be less problematic in a double column magazine if well designed, whereas a single column magazine experiences nosedive as a natural event.

If the gun all of a sudden quits running anything but a round nose bullet something is wrong no? Loading RN bullets for one gun and preferred bullets for another gun is just a band aid in my opinion.
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Must be a burr because it happened with a steel grip as well AND my other gun runs perfect with me shooting it.

Check the leading bottom edge of the breach face. ...does the piece of brass that nose dives in the mag have any marks on the top of it? Like maybe where that edge scraped it?

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Must be a burr because it happened with a steel grip as well AND my other gun runs perfect with me shooting it.

Check the leading bottom edge of the breach face. ...does the piece of brass that nose dives in the mag have any marks on the top of it? Like maybe where that edge scraped it?

I was going to say this too.

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Thanks for those videos. I wish all the gun builders would go out for beer and wings and get on the same page! LOL In my experience gunsmiths have told me to keep my rounds to less than 1.15. As a matter of fact I sent samples with the gun to a very well respected smith and he commented that those are waay too long! They were only 1.165. So Atlas says short don't work and load to at least 1.17? Ugh...

I am getting the nose dive jam, not what ChuckS thought. But I only get it in one of my guns so evidently the geometry is off somewhat between the two. Pretty sure my mags are opened up at or beyond .360 in front. I hate to open them more for fear it will affect the other gun. I have enough mags to dedicate a set to each gun, so I can experiment there.

The funny thing is IT WILL NOT HAPPEN UNLESS IN A MATCH! I suppose I am shooting faster than I think compared to practice?

Also I run spacers and I'm getting pretty close to being too long if I get past 1.17. I just love my good old STI mags and hate to switch everything up for this gun. Besides I just seem to hear nor cons than pros with the MBX mags.

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I haven't heard many complaints about the MBX mags, what are you hearing? I'm thinking about order a couple in the next few weeks. Either that or just get STI bodies and build a couple.

Anyway, the fact that it only happens in a match makes me think it's your grip. (as in how you grip it) You must be doing something under pressure that is causing it. Could it be the gun is running better as it gets hot? For me in practice my gun will stay hot as I run drills and never has time to really cool off. In a match you shoot 20-30 rounds then don't shoot again for a hour. I'd be trying to duplicate it in practice, in hopes that would help me determine the problem.

Have you tried a heavier recoil spring? Take on the buffer if you have one?

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