I am new to roller lock guns.  Spent 8 years in Germany as an Army brat, and I always wanted a H&K MP5.  I recently purchased a MKE Z5P clone, and have a few questions.

I am interested in learning about the mechanics of the gun.  Can some of you point me to links or pages, describing the differences of the locking pieces, and different style bolts, etc?

I have fired close to 500 rounds from mine, both factory and hand loads, suppressed, and unsuppressed.  The only problems I've had were with flat point 147 grain ammo, but after reading several threads,

I see that is not unusual for the platform.  I even bought a couple of books off of Amazon, but none of them really talk about the mechanics of the weapon.  I am a dork, and like to know how things work.

Thanks in advance guys !!

This link to hkpro.com explains the basics pretty well.

http://www.hkpro.com/index.php?option=com_content&view=article&id=135:guide-to-hk-locking-pieces

Thank you that helped !! Now I have another question.  If my pistol is functioning fine with the current locking piece using all ammo types, and with and without suppressor, do I need to upgrade or change to

a number 28 locking piece?  Am I doing damage to the other components of the system?  My locking piece is marked 99, what locking piece would come standard in a MKE Z5P?

My first impulse is that if everything's fine, why would you change?

Analytically and for the long term, "everything's fine" means check your receiver recesses for excessive wear as well as the locking roller surfaces. If everything is truly "fine", then don't change a thing. If not, then a change might be in order for longer-term longevity.

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I have a z5-p sbr. I changed to the #28 locking piece because with a silencer and 147 gr bullets it was tearing up the buffer behind the bolt and I could feel it. With the #28 it doesn't hit it at all and has been 100% reliable, even with the 147 flat speer lawman ammo.

Does it run fine with that locking piece when you aren't using your suppressor, and/or 147 grain ammo?  Just trying to sort it all out.  Do I need a couple different bolt assemblies for running different loads or taking my can off?  Thanks for the replies guys!

as I understand it, the #28 locking piece is only needed when using a suppressor and a stock

It runs fine without the suppressor and with any ammo. I like to alternate 115, supersonic, and 147, subsonic. Every other shot is psshhhh, crack, psshhhh, crack. In my case there was no downside to the switch. YMMV.

I've had the same problem on my K guns using a 100 or 110 degree LP when suppressed. Using LP #28 or 29 does help. The 90-80 degree slows the BCG just enough, but the buffer still gets beats up over time. Best to have a spare buffer on hand jic.