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Posted: 5/2/2011 1:16:28 PM EDT
Hello all,
I'm having a problem with a mp5/40 clone made by Coharie.
Every time I fire a round the ejector get stuck under the BCG and jams it up.
It will cycle by hand no problem, but when I fire a round it will jam up this way.
What can I do to stop this from happing?
Link Posted: 5/2/2011 2:28:36 PM EDT
My Coharie 10mm clone did the same thing when I ran it in FA mode. For the most part it ran fine in semi auto.
Hate to tell you this but the only cure I've found is a complete German HK bolt group.

Having said that you can try polishing the bottom of the bolt where it rides over the top round in the mag and I also chamfered the front corners and their trailing edges on the bolt. I cut a bit off the back side of the 90° nose of the ejector lever (where it goes into the bolt)  and welded a little more material on the hump at the rear of the ejector lever. I was trying to get the lever to move up into the channel on the bolt a bit earlier. I did see some (not much) improvement by installing a HK ejector lever.

Good luck, I know it's frustrating, if you were nearby I'd let you trouble shoot with some factory HK parts.
Link Posted: 5/2/2011 5:06:17 PM EDT
Send it back to Coharie. It might take some time, but they do honor their lifetime guarantee.
Link Posted: 5/2/2011 6:03:51 PM EDT
Thanks for the info,
I was planning on getting some HK parts anyway
Link Posted: 5/3/2011 6:03:14 AM EDT
I agree with clicker,

at least thats what I had to do with mine to get it to work.

I ended up having to get a complete bolt/carrier combo. my cohaire parts were so out of spec, that I couldnt re-use any combination of cohaire and HK parts.

after the swap, of bolt/carrier combo, and a swap to a genuine HK ejector, mine is 100%.

also make sure your trigger pack is sitting at the right height on the shelf. I know my 9mm wasnt and it caused almost the same failures.
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