Piston Stuck in the Back

[Gen. Hospital]

I took the gearbox in my hk416 apart, intending to put in some new stuff, only to discover that the bushings I bought don't fit. I put it back together and set it aside for a few days, but just now I felt like doing a bit of shooting. About halfway through the second mag (150 or so shots), it stopped working. Picked it apart to discover that the piston is stuck to the rear. Now obviously I'll need to open the gearbox to find out exactly what I did wrong, but there's a pretty angry spring in there, and I'm unsure how to proceed. Any pointers? :???:

[Roughneck]

Carefully, I've opened a V2 mechbox with a charged spring before. I unscrewed everything and then lifted the back end of the mechbox up so the spring and piston would go forward, instead of across the room. Before opening, I would also try charging a large battery to full and try a single shot.. that sometimes free's it up. I'm no gun doc though

[The Saint]

There's a hole in the base of the spring guide. Carefully pry open the mechbox just enough to run a screw driver into that hole to hold the guide in place. Don't forget to also hold the cylinder down. With both the cylinder and the spring guide held down, remove open the mechbox completely and carefully remove the spring guide.

[Tex]

to add to the saint's post do that inside a large ziplock freezer bag or anyother clear bag so if something does spring out you won't loose it.

[Gen. Hospital]

Thanks, both of you. I was kinda hoping there would be some pagan ritual or something I could perform first to release that spring. Ok, I guess I should just put on the goggle and get cracking, then.

EDIT: Yeah, I'll get a bag. Thanks :-)

EDIT some More: And I tried "charging a large battery to full and try a single shot..". Now I have a stuck piston and a blown fuse. :-)

[Roughneck]

Originally Posted by Spencer

I'm no gun doc though

That's my disclaimer, my apologies just the same though. It has worked for me.

[Jimski]

what about catching the anti-reversal latch and pulling it ?
not sure you can on a v2

[Gen. Hospital]

I could. There's a hole right next to it, so I used a torx driver on that sucker.

Turns out the piston was unscrewed from the piston head.

[ybrik]

On a v2 mechbox, I would insert a bent wire (shaped to an "L"). Insert in on the motor pinion gear hole and catch and pull the ARL. Spring will be released and piston fully forward.

[ThunderCactus]

I bent a nail 90 degrees at the end and use that to get to the anti reversal. Works great lol
You can try a small hex wrench too but that takes some doing.

[ybrik]

Does this also work on a v3?