Ford don't make the tyres that they put on their cars. Neither does the dealer.
Does that mean they can disclaim responsibility for the goods that they have chosen to provide and sell by describing them as "free gifts" if they explode as soon as you drive away?
Well if a tyre explodes (bit drastic using explode), you would likely have driven over a big friggin' nail
and if there is massive nail nail sticking out of the tyre I doubt if that would be covered under warranty
Also certain extended warranties will not cover certain parts like brake pads, tyres, clutches that will always be prone to wear n tear
If you have ever bought an ultra cheapo chinese battery for your mobile etc....
You will quickly realise the capacity say on G36c saying 1100 mah is more like 50% to 75% in real terms
Very often those cheapo batteries are severely mislabelled - aka they tell f**king lies
Go & buy some cheap 3034 mosfets from fleabay and see how long they last
Forgetting the daft analogies a second & back to topic......
Patrol Base don't actually disclaim or refute the battery/warranty as such
They state the battery & charger WILL FUNCTION PERFECTLY....
ergo they are to all intentional purposes GUARANTEED
So the OP could send it back for replacement
Personally I think Patrol Base have f**ked up
I would have stated clearly the battery/charger are not covered/guaranteed
Even decent Vapex Nimah's lose efficiency and hold charge less & less as they get old
Soon as one 1.2v cell starts to go it quickly becomes f**ked
So I would have sought to borrow another battery first and tested the gun
TBH at some point like Patrol Base say you should get a better battery/charger
and quite likely you would make the jump to LiPo anyway imho
The dimensions I gave was a JG battery with a 34mm width
however there is a plastic end cap at top where wires are situated which is wider - easily 36mm
So that LiPo "should" fit quite well -but I'm not offering a 200% guarantee
It is the owners responsibility to double check a battery dimensions and factor in a couple of mm's
to allow for margin of error or a tiny bit of swelling as well as including extra wires - say LiPo balance lead
I'm pretty sure you could a 2500 mah 7.4v in there - maybe squeeze in a 3000mah if you really triple check the sizes
Even a 3cell 11.1v can fit but would be a smaller capacity of about 1300mah due to the extra cell
The OP is more than welcome to pack it up, ring a courier or shuffle off down the post office....
Wait a week or so, but me personally if the battery is at fault I would be tempted to say $hit happens and go LiPo
Even a decent 1600mah Vapex might only last him 3/4 of a day, so that cheapo battery would be lucky to last half day
So at some point he would need to buy another battery - and I'd be f**ked if I'd pay £15 for a nimah battery....
https://www.componentshop.co.uk/8-4v-1600mah-2-3a-nimh-mini-battery-pack-3x2-1.html
I'd try another battery and/or ring Patrol Base before sending complete gun back but up to OP in the end