Took my 9mm build out to the range for the first time today and was experiencing a lot of frustrating problems with feeding and ejecting. I'm in dire need of advice.

Problem #1: chambering a round. I release the bolt and the round gets jammed. Happens with virtually every other round. video here

Problem #2: stove piping. I'm frequently experiencing weak ejections as well. Video

I used 147 grain FMJs. Not sure of manufacturer. I think Winchester.

Here's my relevant parts list
Upper:
-VLTOR MUR 1s (shell deflector only)
-CMMG 9mm bolt (narrowed for Glock mags by ADCO)
-ADCO 5" barrel with DPMS 5.5" flash hider
-Seekins 7" SAR rail

Lower:
-DDLES small Glock frame lower with factory 33 rd mags
-Stag Arms lpk
-Slash's 9Q heavy buffer
-JP tuned and polished carbine spring

I believe the problem lies in the upper since I put that together myself (also my first time putting together an upper, relevant meme). I've previously slapped on my buddy's CMMG Mk9 PDW upper onto the DDLES lower and it ran flawlessly with the 300 rounds I put through it.

Compare the bolts between the two. Sounds like  something is impeding the bolts forward progress, either scrubbing  a mag feed lip or dragging the ejector. Both can cause the issues you have. Try just your buddies bolt in your gun.

EDIT
Just got to the office so I could see your videos and it looks like you have two problems....do you have a crease in the case where it is hanging on the chamber mouth? Probably needs to be radiused a little and that will go away....stove pipe looks like the ejector is throwing the case into the edge of the ejection port.......this is why I open the ejection port on a DI45 and 10mm as well.......not a lot of tuning possible with the ejector on a glock lower....but if you slooooowly extract a spent case......you might see where the case is hitting the port (If that is the in fact the problem)and be able to bevel the ejector to redirect. You will also want to verify the bolt is not dragging on the ejector........it does happen. If it is....just dremel a little off the top of the ejector......always modify the cheapest part .

Where in Tn are you? I live in Knoxville and could give you a hand.

My friend's bolt isn't modded for Glock mags. I swap out his bolt for mine when using his upper with the DDLES lower.


I will take a look at my AR when I get the chance. Hopefully I understand what you're saying and know what to look for, haha. If its of any relevance, I used snapcaps to check if they cycled properly prior to taking the gun out to the range. Didn't have problems iirc.


Memphis, unfortunately.

Take your upper off of your lower.  Try to place a round in the chamber.  Does it go all the way in and stop on the case mouth like it's supposed to?  Does it drag on the chamber opening?  Insufficient taper crimp (or "flare removal") can keep a round from chambering, and it's not easy to see or feel, so the best way to check is trying a round in the chamber.

Also make VERY sure the ejector on your lower is properly positioned.  If it misses the TINY space on the case head, the new round will push the case off the bolt face and will look like a stovepipe.

How deep should the round sit in the chamber?

My ejector seems very loose and wobbley. Is that how it should be? pic

The round should stick out about 0.135".  Use a caliper depth gauge to see if you're close.  If it's too high, the bolt won't be far enough closed for the hammer to hit the firing pin properly, and if it does, the case will bulge or worse.  If it's too low, the bolt won't fully support the case, and the firing pin may not hit the primer.  Edit to add: Looking at your picture, it seems the round is WAY too high in your chamber.  Measure how far out it is, and let us know.

The ejector should have a little play to keep it from getting bashed about.  

In your picture, the ejector seems like it's "pointing down."  The top MUST be parallel with the top deck of the lower (and thus parallel with the groove in the bolt).  It must ride as high in the bolt's groove as possible, and the FACE of the ejector - that tiny little rectangle on the front - must be perpendicular to the bolt axis.  That's all there is to knock that 9mm case out, and only about 1/2 of it actually contacts the case head, so alignment is crucial.

With upper off the lower, drop a cartridge into the chamber, and drop the bolt on it... does it look like this ?



I see on the arch/heel of your ejector in your pic that there appears to be some contact marks... inspect bottom of bolt in the channel for offending-matching rub marks.. reports is DDLE ejector hits rear of slot in bottom of bolt due to insufficient machining to allow clearance of ejector.. pic references how ejector face should align with bolt face for maximum contact to hit empty out of the upper

SBR, can you toss in your picture showing how little potential contact the ejector has - the bolt face picture above with your added comments?  I think it says a lot about how important ejector location and position are.

Good morning,, as requested -  ( I really need to take better pics someday and make better with the paint though)





This one here is mine... slight low, getting it toward center of case is really important for maximum case contact, but height needs to be there too....  never had exit failure that I can recall

I was having all kinds of problems with my DDLES 40 S&W build, tired all the usual recommended stuff and still constant ejection & jamming problems. finally I bent the tip of the ejector a tiny amount, less than 1/16 in towards the ejection port.. Now it works perfectly with my 40 & 9MM upper.

It was just the angle of the photo that made it appear to point down. My apologies.

SBR7, the position of my ejector looks fairly similar to yours. I'm going to try to bend the tip of the ejector a teensy bit to see if that improves anything. I dropped the bolt down on a cartridge (with upper removed from lower) looks like your photo as well.

I'm starting to think some of the problems I'm experiencing is related to the ammo I was using. I have a few hand loads left over from my friend and those seem to cycle fine. I'll buy some new ammo eventually but it's going to be a while until I can hit the range again to test. I'll be sure to come back with updates.

I really appreciate the wealth of knowledge, guys. I'm learning a lot from this experience!