Big FPS variations on Krytac LMG

[Stevo4345]

Finally got home and got my mitts on the Krytac LMG-E. Like it, like it a lot, compact but solid looking. Charged up the 11.1 1300 mAh Li-po that came with it, all good according to the B6, figured out how the box mag works (by taking it apart and poking about), filled it up with 0.2’s and gave it a go. High ROF, way higher than my Specna, feeding just fine from the mag, electric wind keeping up with the deluge of bb’s spitting out the pointy end.

Time for the chrono, ah, high of 295 FPS, low of 255 FPS. Hmmmm

ROF at 23 per sec.

Obviously some air seal issues going on, so out with the tools, broke the Krytac seal and got stuck in.

All came apart as expected, gears were well greased, no sign of wear. Return spring for the trigger switch was loose so fixed that. Nozzle was dry as a bone and piston head o-ring looks like it’s too tight and also pretty dry.

Got some silicone grease ordered, as well as some lithium grease for the rails. Question is while I’m in here should I get a better nozzle, maybe one with an o-ring seal? Don’t want to go mad, figure some grease in the right spot and a new o-ring will do the trick. Also what size are those piston head o-rings and where do you get them from? 
It’s going to stay in bits till the lube arrives so I’ve time to figure it out.

Will convert it to Deans while it’s on the bench, other than that can’t wait to get it on a skirmish day.

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[Stevo4345]

Right, first off kudos to the techs that tear gearboxes down day in and day out, it’s harder than it looks!

Got my new bits today, cylinder head, nozzle, grease and o-rings. Got the cylinder together, night and day difference, great air seal even with nozzle in extended position.

Put it back together, test fire, 1 shot and lockup! Tore it down, forgot to put the anti reversal lever behind the 1st gear, d’oh, fixed that, back together, test fire, one shot then lockup! WTF!

This time the cut out was binding up, sorted that, reassembled, semi working fine, auto working fine, oh the relief!

Got the mag on it and test fired, picking up bb’s just fine. Onto the chrono, what a difference! 338 to 345 FPS, 22 RPS, full auto feeding well, semi also. Put about a thousand rounds through it, cut a few paper targets in half.

Chuffed to bits with the result.

@ak2m4 Spot on with the nozzle and cylinder head recommendation, worked like a charm.

Now I just need a poncho so I can play in the rain!