Who ever set up the gun was probably one tall Oedipus Rex! I am 6'3" with long arms and like a 13.4-14" LoP on full size rifles and shotguns. 14.5" LoP was kind of excessive. I found a good compromise between comfort and clearing the drum. The gun worked well as a .380 (except for multiple feeds from the factory Zytel mags with stretched out feed lips). I had one Zytel unload itself in my range bag on a bumpy road. I'm on the waiting list for the second batch of Shockwave Technology ZMags (due late August).
There were some issues with the Lage upper jamming when switching from Auto to Semi. I had a badly worn trip, a weak disconnector spring (disconnector side of the trigger spring). However, the jams were most likely being caused by a badly bent pin retention spring sticking up into the path of the Lage bolt (this moves even higher when rotating the selector which is what caused both jams) and a slight misalignment coming form the fact that as received form the dealer, the gun had a slightly smaller diameter MP5 takedown pin instead of a Mac pin.
Richard bent my pin retention spring back to the proper shape. It serves no other purpose but to hold the trigger pin and selector in place. I replaced the trip, disconnector and trigger/disconnector spring with the Lage competition auto-only trigger which made those parts redundant. I also went with the Lage hardened steel internal safety block, extended external safety catch, and Lage takedown pin. Total damage was just under $170 with tax to get it running well. I'm usually not price conscious but just bought a 40 acre hunting property in the Zuni foothills and I have a long market position so I am cash-poor right now (Clinton-style "broke"). I have a Galil stock hinge rebuilt kit (pin, spring, moon clip--$15) on it's way from Bonesteel Arms which should tighten things up. The final stock bending, drilling, epoxying and pinning will be done when I see how the hinge sits when open and under tension. With the worn pin, it currently sits a few degrees counter clockwise in the mount. Whatever set it takes with the new mount, I will put a compensating bend in the stock so that the buttplate is straight.
As I do on all my slick plastic and even metal military stocks, I covered the buttplate with rubberized cotton friction tape. It really grips clothing well. I don't think the recoil will require me finding a 7.62 style Galil stock with a built-in rubber pad. Although I have found that the "shake" is hard on the scope mounts. I'm going to see if this 16mm high cantilever mount is strong enough after re-tightening it after it loosened slightly while firing about 500rds. If not, I have a 20mm non-cantilever mount and I'll add a 4mm paracord wrap to the stock. I found 1/2" and even a 15mm mount to be too low.
Range report: what can I say? It's hot as hell outside! I went out to the desert in the evening a couple times and shot some steel jacks and plastic resealables at various distances after bore sighting. Used about 7 or 8 72-rd drum loads with Rem yellow box 115gr. All but one drum worked flawlessly--I caught that drum getting stuck internally so it is not the gun's fault. It happens to be my most rusty drum (internal and externally) of the 8 with bad pitting of the plate behind the scroll. I had to modify the feed ramp on one (was hitting the scroll before the stop and jamming--that one is one my my nicest now). I may just have to increase the spring pre-tension by a turn or so.
700 rpm feels kind of slow. Even with the buffer spacer that adds about 10%, it sounded more like a typewriter than what I expected from a machine gun. In fact, it sounded uncannily like typing. :) I need to go to a proper range to get it sighted in.
I noticed a little rise after the first 4-5 rounds. Will probably pick up the Lage reverse canted grip to fight the rise.
I'll be trying it with my Ti-Rant .45 next. I am on the lookout for some inexpensive 147gr subsonic. I usually have a lot of fun with suppressed guns but not sure I will like shooting the MG suppressed. It is a toy for turning money into noise after all . . .
Mike