I bought a DDLES 9mm colt style lower 2 years ago and finally got around to making a SBR. After putting everything together it is very hard to pull the bolt and charging handle back. I read everything I found and nothing helped. I pulled out the ejector and now it moves smoothly. Im using a CMMG ramped bolt and a standard CMMG lower parts kit and those are not the issue, it is just the ejector. Should I file it down or get a new ejector? But then again the company is out of business.

What should I do here?

Thanks, Steve

This is a known issue with DDLES/QC10 Colt style lowers and CMMG BCG.  The ejector does interfere with the bolt.  If you look closely at the groove in the bolt where the ejector rides, you will probably see marks where the ejector was rubbing.  Some folks elected to dremel a little bit of material on the back side of the ejector and the outside elbow.  Others actually dremeled the bolt area.  Most people had the symptom of not being able to close the upper and lower together and get the takedown pin in.

I can't tell from your description how bad the interference is.  I had this problem and the only way I could get the takedown pin in was to get the pivot pin in first, then mash the upper and lower together as far as I could, and then pull the charging handle back until the bolt cleared the ejector.  This let me get the takedown pin in.  Once it was in, the bolt was able to cycle ok by hand, but probably never really went into full battery.  I could tell that it was very close and so I dremeled the channel in the bolt where I could see the ejector was rubbing.  It didn't take much, and now my gun runs great.

Others have dremeled their ejector and they were able to get their gun running fine. If the interference is minor, its easier to take a little bit off the ejector than dremeling the bolt. I could have done mine either way.  Sounds like your interference may be severe so you might have to figure out why your ejector is riding so high up.

Assuming everything is put together (including barrel)  the bolt ramp may not line up at same angle as ejector thus requiring the back of the ejector to be filed down slightly.   Quarter circle 10 now produces these lowers and they have spare parts.

Thanks for the replies guys, but I finished filing down the ejector already and now it operates smooth. Hopefully i'll get to test fire it this weekend. It wasn't off by much but it was a pain in the ass to put the take down pins in. Had to do the same thing as far as open the bolt just enough to push in the rear pin. I wonder if the new ejectors are a much better fit, I wouldn't mind getting a spare.

I did the dremel mod to my bolt. I was having lots of FTE's and finaly fixed that by bending the ejector very slightly to the right. Now it runs flawlessly with 40 S&W and 9MM uppers.

Took it out and shot it today, had several failure to eject. Im thinking I need to file down the ejector a little more. Also notices the ejector is very loose from the factory and if it is all the way to the left it does not eject. Instead it skips by the casing and the jams with the next loaded round. Maybe ill try to bend it to the right.

Before you bend it try shimming it.

So far I have only dremeled it down a little more and it seems to manually cycle smoother and using dummy rounds it loads and ejects fine. I'm going to wait until I shoot it again and see what happens before my next move.

Hopefully i,ll get out this week sometime to test but definitely next weekend at the latest.

Does anyone know if this is still an issue with the quarter circle 10 lowers?  I was getting ready to use one of their colt lowers i ordered last week with a CMMG bolt.  Any info is appreciated.

I built my QC10 Colt SBR with CMMG Bolt in December last year.  It was an issue with mine, but a member (slogoat) here showed me what he did and I copied his solution successfully.  The gun runs great after dremeling out the bolt slightly where the ejector rides.  Not sure if QC10 has done any mods to the ejector, but taking off a little of the back and outside elbow of ejector would have also worked.  I guess you pretty much have to assume you'll run into this same issue.

Hey bud, glad to hear its been running good! I wish I could remember which thread I posted those pics in so we could link them here. I imagine DDLES was somewhere in the thread title.



ETA: If you have a dremel, using one of the roughly half dollar sized cut off wheels keeps the curve in the bolt channel almost idential in shape while removing material. Thats what I used on the bolts I've done. (got a couple of these DDLES builds under the belt)

I must of missed this. Will have to  try some dummy rounds tonight

Know of any bolts that wouldn't have this problem?

Well I installed the barrel just hand tight since no torque wrench present and cycled with the cmmg bolt. I had no issues. I loaded up a magazine with dummy rounds 8 times and other than the magazine being difficult to seat with a closed bolt, it cycled, chambered and ejected the rounds with no issues and held back after last round each time.

Will see real test whenever I get barrel torqued and live fire at range.

Edit: using an aero precision M4e1 upper.

Hey Slogoat, thanks, Man.  I found that thread with your pictures.  It sure helped me, and I'm sure all the other guys that caught your advise and pictures as well

DDLES ejector interference with CMMG Bolt

ETA: reading that old posts, I remember now.  I initially fixed it by dremeling the ejector.  But a couple days later I replaced the ejector and dremeled out the channel in the BCG for the permanent fix.  I took a bluing pen to cover where I ground the channel (probably didn't have to do that since the channel stays well lubed).  I didn't grind much at all.  This seems only to occur with specific upper receivers.  Mine is a VLTOR MUR-1S that had the problem, so there will be some of you with different uppers that won't run into this

I'm glad im not the only one with this issue. Its reassuring to hear so many others have dealt with it before and this seems to fix it. I dremeled the ejector but wont be able to shoot it til this weekend.

http://www.ar15.com/forums/t_3_15/661349_Take_down_pins_not_going_in.html

Yeah the amount of material that must be removed is minimal. I'm running the same upper as you on both builds I have, and had to modify the bolts on both.

My first post here, so please excuse any noob etiquette mistakes.

I don't have a DDLES/QC10, but I own a close cousin, the JP Rifle GMR-13.  The bolt carrier does rub against the ejector and you can see the ejector wear from day one just dry firing it multiple times with a Laserlyte 9mm cartridge to zero in my optics.  And sometimes the bolt can be very hard to pull back because it's rubbing on the ejector.  This is with the Gen1 JP 9mm Glock bolt.  I have since upgraded the rifle to the Gen2 bolt and it's much more smooth and has much less rubbing in my opinion.  That said, I can't say enough good things about JP.  I guess I'm a JP and HK fanboi.

For my second Glock build, I made my own Glock magwell, took the Gen1 Glock bolt from my JP and installed it in my Palmetto State Armory 9mm pistol upper (sold the original PSA 9mm bolt), and installed an Olympic ejector in the PSA 9mm upper.   The Olympic ejector is pure genius (in my opinion) because it auto-adjusts to the JP Glock bolt.   It works perfectly with Glock mags.  (No, I'm affiliated with Olympic arms).  

Here's a couple of pics.  Hogan billet lower with my own Glock magwell, PSA hybrid Colt/Olympic pattern upper.  I'm only using cheap Blazer FMJ and it's running perfectly (feeding, extracting and ejector perfectly with Glock 18 and 17 mags).  

http://i57.tinypic.com/11gm882.jpg

http://i61.tinypic.com/mx1191.jpg

http://i59.tinypic.com/nyaf01.jpg

The amount of material is so little, using a file works better. Unless people have forgot how to use one

Use them every day at work.

I have a DDLES Glock lower, one of the first out of the shop (serial # is single digits 005 maybe?) and a bolt ramped by them.

Maybe I should build it up and see how it runs.

I got so tired of waiting after putting a down payment on one and waiting over 2 years to get it, when I finally did, I had moved on to precision shooting and just have not messed with it.



Is this issue only with the COLT ones or does it exist with the Glock mag models as well?

Believe it has to do with colt version only depending on what upper you're using.

Most common issue with glock version is the last round bolt hold open

Cool, upper was built but ADCO using a Spikes 9mm upper and I let them go from there. I really have no excuse not to build the damn thing up. I have all the pieces and parts.