Gen 9 nylon only firing 1 shot

Hey guys,

Another newbie. Ive attempted to upgrade the 0 ring and spring. But after putting the gearbox back together, i only get 1 shot before the plunger jams. Any ideas on what can be causing this?


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Hi, could be you didn’t fit the tappet return spring?

Have you got any pics?

does it fire again when you move the selector switch?

No the cylinder jams up completely

I dont have any pics right now but will take some when i get home this afternoon. Tappet spring is on though

Does the motor still run and gearbox cycle whe it jams or does the whole thing lock up?

Full jam up. I tried with the stock spring and got 3 shot but still jams up. It pulls the plunger out at different lengths after i reset it. It seems to completely cut out

So only o’ring and spring changed?
Anti reverse latch in correctly?
Are the plunger and tappet plate sitting in the grooves correctly?
I’d suggest pulling it back down and re-assemble. I reckon you’ll see something not sitting correctly. If you haven’t done too many before do it in front of the computer with a Low Guido clip going and do a step by step build pausing as you go to watch the next bit etc.

Yeah only o ring and spring. Yeah ive pulled it apart a few times while watching videos. Ill get some photos up later today. Worse comes to worse ill get a new gearbox and look for the difference

What if you turn it over with a screw driver and watch what happens, it’s not something silly going on with the pinion gear is it? Motor not sitting in place and pinion to bevel gear jamming?

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Id like to think not but wouldnt put it past me. Ill give that a go thanks

this is easier to do without the piston spring but worth doing

make sure your sector gear isn’t fouling on the trigger block

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Can confirm its not the sector on trigger block. Already ran into this and resolved it


the hand cycle will still be valuable to find what is going on with your jam issue :slight_smile:


Nothing like a good hand cycle :rofl:


sometimes…if you want a ob done right…you just have to do it by hand…




I got a chance to hand cycle on my lunch break and have a possibly dumb question. How hard should it be to engage the plunger teeth? Everything turns smooth but the first catch on the teeth requires a little more effort.

You may have an AOE issue

or the plunger not in it’s slots properly?