Jump to content
Brian Enos's Forums... Maku mozo!

What causes this kind of Feed Jam ?


Jumbo30

Recommended Posts

I don't know what this type of feed jam is called, but I'll try to describe it.

EAA Witness, Small frame steel, New .40 S&W conversion, Factory Win JHP.

The bullet moves up the feed ramp and then hits the top of the barrel and can't make the turn, down into the barrel?

The feed ramp has been polished and the lip of the mag has been opened up (the round used to just go straight into the feed ramp).

Is this because of the JHP? Would the updated mag release fix it?

I searched the forums and found things on "nose dives" and magazine problems but nothing on this.

I hope it's something stupid or simple. Yes I am a newbie to all this.

Any help would be appreciated.

Thank you. Jon

Link to comment
Share on other sites

Hi Jumbo, and welcome!

Does the gun do this with all your mags or just one? I think mags lead to a lot of feeding issues that get overlooked.

Hi Kevin. They are new mags that came with the conversion. They are the "California" models with the plastic bottom. My 9mm mags have a metal bottom, so I don't know if these are cheap versions or not.

Here's a pic of the jam:

post-35458-0-92445000-1321573997_thumb.j

Link to comment
Share on other sites

this looks very similiar to the problem I had. It was caused by a combination of factors...the breach face needed polishing, and the extractor tension was too strong. I also polished the front to bottom edge of the extractor and the inside rim of the extractor so the brass move easier as it loaded into the chamber.

Link to comment
Share on other sites

I had the same type of issue with my CZSP01 in 9mm. The Remington UMC rounds were shorter than the Winchester White box i normally used, and they would jam. You may need to find a brand of ammo that's a tad bit longer. that's my only experience with CZ and this type of jam.

DSCF1485.jpg

DSCF1484.jpg

DSCF1479.jpg

DSCF1476.jpg

DSCF1474.jpg

Link to comment
Share on other sites

It looks like the shell is having a hard time sliding under the extractor.

Is it normal that an out-of-the-box kit need this much work?

I'll look at longer ammo too. I do think that FMJ would probably work better regardless.

Thanks everyone.

Jon

Edited by Jumbo30
Link to comment
Share on other sites

Okay, just to wrap it up...

The extractor was stiff. Removed it and there was a big glob of rust around the spring. I guess I'll know better now that "new" probably has been sitting around for a while and to take it all apart even though it's all nice and lubed up on the outside.

All clean. I polished up the extractor and breach. Can't wait to shoot it.

Thanks all.

Link to comment
Share on other sites

Okay, just to wrap it up...

The extractor was stiff. Removed it and there was a big glob of rust around the spring. I guess I'll know better now that "new" probably has been sitting around for a while and to take it all apart even though it's all nice and lubed up on the outside.

All clean. I polished up the extractor and breach. Can't wait to shoot it.

Thanks all.

While you are at it, check your firing pin and firing pin spring as well. Part of the extractor channel intrudes into the firing pin channel. If you got rust in one place, it may be present elsewhere nearby.

Link to comment
Share on other sites

I shot it today. Still had feed issues with the JHP. Not really bad like it was. Hitting the back of the slide finished it off. Bought a box of FMJ at the range and those feed well... 1 misfeed in 40 rounds. The bullet just went straight into the feed ramp. Hit the back of the slide and it went in. I switched back to the JHP and the rounds fed better. Only a few miss feeds per 10 rounds. It's new so maybe it's getting broken it?

Got home and noticed a lot of brass flakes and a brass color on the "face" of the extractor. I guess the "color" on the extractor is from hitting the slide closed. I worked on the extractor a bit more... worked on the front of the slide a bit too because it felt like it could be sticking a bit when the slide was all the way back. Also ordered the updated mag release and some mags from Henning. Hopefully that'll fix feed issues once and for all. Anyway, the gun shot great! All rounds in the black @ 15 yards and the recoil wasn't harsh at all. Once this is fixed I'll graduate to the 25 yard range!

Skydiver, I pulled out the firing pin and yup, there was rust. Cleaned it all out as obsessively as I could. Haven't worked up the nerve to disassemble the gun beyond that. I'll have to watch Henning's video a few more times!

Link to comment
Share on other sites

sounds like too much tension again....just tapping the back of the slide to close the slide sounds exactly like what I had to do (Look at the head of Hennings extractor in the picture about tuning for rimless...he has done some work to it. ) The casing should not be a labor to slide up under the extractor.

How does the slide ride in the frame with the barrel and guide rod removed? It should slide freely. Complete guns are usually checked for fitting at the factory..where as the kits are not. I recently had to fit my .38 super slide to my .40 frame.

Edited by Mo Hepworth
Link to comment
Share on other sites

sounds like too much tension again....just tapping the back of the slide to close the slide sounds exactly like what I had to do (Look at the head of Hennings extractor in the picture about tuning for rimless...he has done some work to it. ) The casing should not be a labor to slide up under the extractor.

How does the slide ride in the frame with the barrel and guide rod removed? It should slide freely. Complete guns are usually checked for fitting at the factory..where as the kits are not. I recently had to fit my .38 super slide to my .40 frame.

This is a VERY good point. The best way to check frame to slide fit is to take out the barrel and guide rod from the slide, then take out the trigger/trigger bar, sear cage and hammer from the frame. Taking out all of these parts will ensure that the only friction between the slide and frame will be the quality of the fit of the rails to one another. With the dissassembled frame and slide slip the slide onto the frame and see if it slides friction free through the normal travel of the slide would have as the gun would cycle after a shot. If there is ANY friction or binding felt when testing it this way you need to work on the rails to make sure that they are fit to one another well.

I have gotten replacement uppers from EAA that went on and fit perfectly without needing any tuning. But these are rare. Some amount of rail fitting is needed to produce smooth and friction free function most of the time when you get a replacement upper.

Link to comment
Share on other sites

  • 2 weeks later...

Finally got out to shoot the gun today. Yeh Mo, Nealio and all that called it, it's extractor work that fixed it... zero misfeeds. JHP, BJHP, FMJ.

FYI, I installed the updated mag release (my gun's a steel small frame) and it positioned the mags way too high (maybe .125") I looked around and saw that there are mags with a "stepped" lip and maybe those clear the slide but those are for the large frame(?). Anyway, ground down the top edge of the release to lower the mag and it works great. I guess nothing is plug and play?

Anyway, a funny thing with this conversion is sometimes when I load a mag when the slide is locked open, the slide releases and chambers a round. Startled me the first time that happened... I think maybe the mag is hitting the slide release?

Anyway, thanks for the advice.

Jon

Link to comment
Share on other sites

When you seat a mag some times it jars the slide enough to allow the slide lock to slip off the notch in the slide. If you don't want this to happen you can reshape the slide lock lever and slide notch so they have a more secure engagement.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...