Breaking tappet plates... Help!

Hey all.
I need to pick your brains.

Having an issue with my blaster. It eats tappet plates. I have lost 2 in the last month and they have both failed at the gear end before the fin.

I have read a few other posts with similar issues but didn’t find any with solutions in them.

Gearing is shs 18:1, tappet is wells nylon peice as is the cylinder, head and nozzle although these parts are aftermarket for the well. All encased in a mk v2 gearbox case with shs bushings and a 1.28 spring.

I did see suggestion that the wells nylon tappet plate may be too short/head too thick causing stress when the plate is pulled back with the nozzle fully retracted?

Any ideas on a fix or a tappet plate that may be a little longer?

put just your gears in and tappet plate with nozzle no spring. close g box up. push tappet all the way back. now rotate your gears and feel if it meets resistance on the tail of the tappet plate as the sector rotates past. if so shave a little off the tail till no resistance but still get full stroke.
While you are at it check the upper part of the tail is not binding / rubbing on sector gear.