Jammed upgraded airsoft gearbox

Have GUN questions? Ask here.

For general & advanced questions about Airsoft upgrades, maintenance, aftermarket add ons, etc.

This is NOT a forum to ask for general Airsoft Help. If you want that, post in the General or Newbie sections.


Post Reply
Posts: 1
Joined: Mon Oct 20, 2014 4:20 pm

Jammed upgraded airsoft gearbox

Post by poodlepoodle » Mon Oct 20, 2014 4:51 pm

Hello, I have just upgraded my gun with all these part's-
Lancer Tactical Tappet Plate Version 2 OEM By SHS
Lancer Tactical Fiber Reinforced 7 Metal Tooth Piston OEM By SHS
Lonex TITAN Airsoft AEG Motor - High Torque / Long
Matrix M125 210% Irregular Pitch Airsoft AEG Upgrade Spring (400~470 FPS)
and a new barrel and flat hop up.
This was all done on a VFC Scar-L STD

This was my first time upgrading a gearbox, but when I was all done I tried to fire it, it locked up and didn't turn-over...(jammed) I flipped the motor to see if it was hitting the Anti-Reversal latch, but it still didn't fire. The shimming was done fine, (move's smoothly) as you saw in my upgrade list, I have a very nice motor and a 9.7V battery...so no issues with power. Any ideas on why it's locking up? I really have no idea at this point.

Kenny Barnish

User avatar
A Regular
Posts: 167
Joined: Fri Mar 01, 2013 1:38 pm
Location: Hutchinson Mn

Re: Jammed upgraded airsoft gearbox

Post by neoM4tech » Mon Oct 20, 2014 8:41 pm

Running off the term lock up (gearbox sticking on itself) rather than the term jamming (feeding issue of some kind) These are the things i check:
does the piston slide smoothly on the rails when the gearbox is screwed together with nothing else in there? obviously with a spring on gears the piston will hit those, so they need to be out.

is the piston seated properly in the grooves for its rails? often a piston will wanna jump out of place as you close it, one of the many many things to watch for as the shell closes. along with this make sure the tappet can move freely, although the tappet wouldn't cause a jam, it can cause feeding issues, might as well check it.

is the replacement spring longer than the stock one? along with this goes do you have a bearing on the spring guide AND piston head? too many parts taking up space can block even the smoothest piston from moving back far enough for the release tooth of the sector gear to get out of the way. if you have both bearing take the one off the piston head.

is the arl in properly? if its installed wrong or jumped out as you close the shell it can prevent gears from moving properly.

answering these questions should either find your fix or lead us in the right direction to where the real problem lies.

User avatar
Guges Mk3
MAA Member
Posts: 8840
Joined: Thu Jul 12, 2001 3:01 am
Location: MN

Re: Jammed upgraded airsoft gearbox

Post by Guges Mk3 » Tue Oct 21, 2014 8:48 am

Also not all batteries are created equal.

One 9.6V is great while another one is woefully inferior. Please supply details on the battery.
I rather use a "nightmare" that shoots like a dream over something that looks like a "dream" but shoots like a nightmare.

Don't fear the gun...fear the one that's wielding it!

Post Reply

Return to “Help Forum”

Who is online

Users browsing this forum: No registered users and 1 guest