TM L96 loading issue?

[FireShark03]

Hi everyone,
I have got a tm l96 full upgraded with PDI parts but for some reason it seems to not load BB every cock.
It gets stuck/jam I'm guessing in the loading rail or maybe somewhere else.
It's only done it with the PDI parts in and I'm not sure why as they were specially made to work with this gun and I'm just getting annoyed with it.

I've took the gun apart once when it jammed and a bb had got stuck in the load rail. Even dry firing it cocks fine, if little tough and needs to be certain angle.
I don't want to use the stock cylinder and stuff as it's far to low fps to use as a sniper and you can't remove the head as it's not a screw in on the stock tm version.

Hope that makes sense.

Anyone got any ideas?