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MP7 cycling issues

4K views 11 replies 7 participants last post by  Lamont 
#1 ·
Hello all,
I have a MP7 in the shop with cycling issues in FA.
I tore it completely down and cleaned all the fouling out of the gas system and gave a thorough scrubbing.
It will run fine without the B&T suppressor but when I attach the suppressor it begins to act as if it is having gas issues.
So I am wondering is the gas system on this adjustable? I see how it "could" be done by loosing and backing out the set screw that allows cleaning access to the gas system but I do not see any indicator marks on the set screw that would suggest it was meant to be adjustable.
Any pointers?

Thank You
Michael
 
#2 ·
You mentioned tearing it "completely down". Did that include removing the barrel and gas block? I'm not aware of anyone outside of HK with the tool needed to remove the barrel, which allows access to remove the gas block. Doing so will allow you to clean around the gas port. Not sure how many rounds your weapon has had through it, but I've seen several that were "range rentals", where the gas ports is clogged up and causes cycling issues.
 
#3 ·
Did not remove the barrel. If need be I was going to fashion a tool to remove the barrel. But I did have the gas block out(the barrel nut is behind the gas block) and cleaned all the fouling from inside that. It was considerable as the "owner" of this weapon does not do his own maintenance.
 
#5 ·
I want to tear the can apart but waiting on a breakdown tool. The rest of the stuff mentioned looks good and clean due to me actually taking apart and cleaning.
As far as the can building pressure that is my train of thought as it will increase back pressure and hence the thought that the gas system would be adjustable on the MP7.
 
#6 ·
The most overlooked maintenance on a MP& is the magazine. Did you disassemble and clean the magazine? Have you tried function testing with a new magazine, or mag spring? The cyclic rate naturally increases with any use of a suppressor. This can expose the weakness in a magazine spring. If the spring is unable to deliver the next round to the feed paw at the faster rate, a malfunction will result.
 
#9 · (Edited)
I have an MP7 that we used for many demos--most of the time using burst fire and mag dumps with suppressor (AAC Mini-4). After many thousands of rounds, we began having difficulty with the weapon that could not be solved by any of the normal user-level actions or maintenance. I opted to have the weapon sent back to HK where they performed cleaning and maintenance not possible anywhere else than at their level. The weapon is once again perfect.
 
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