Double Bell AK74U Upgrades

The m120 I would say is also a must. Only a few stock gearboxes will handle that though.

When you say jamming is the gears jamming or gels jamming?

the gels are jamming i just short stroked it another gear its still happening

When you said your gearbox is jamming I thought you meant the gears were locking up.

If gels are jamming it’s more likely gels oversized or not enough air seal and or pressure to push the gel out.
Apaches can be a pain to setup, I don’t like them and would rather a tappet plate setup unless it’s an Airsoft box that just won’t allow enough travel but that just me.

Check it is sealing between nozzle and tpiece. What gearbox do you have?

Need to spill some details of parts and mods to get an idea of what is the cause here

its just a basic metal v2 gearbox the normal ones not cnc

I suggest, making your own thread on this. You’ve hijacked a thread unrelated to your blaster here, it will be confusing.

But also, details required. Parts, brands, barrel length, parts and mods used etc.

I am happy to help but if you are going to be low on the details my ability to help you is too.
Pictures are helpful too.