Simply put - Cyma is best under £100 M4 out there
(or one of the best)
heck how about £60 for one:
https://gunfire.pl/product-eng-1152216180-SRT-28-Assault-Rifle-Replica-Tan.html
That is half the price of a G&G & you don't get battery for shelling out £120 or so
Nuprol - seems good but the microswitch should have a mosfet
ASG think comes with mosfet & stuff looked decent - tried to buy one but my UKARA has expired
Classic Army seem to have upped their game though, 9mm bushings, rotary hop, QD spring, mosfet
https://swasairsoft.co.uk/airsoft-guns/classic-army-m4-12-mlock-rail-black-aeg-2
ooooh now this looks a real possible G&G beater all at that silly price
here is what might be inside btw....
under £100 - probably around the £85 mark - Cyma if funds are tight
once you get over that most likely G&G but the new Classic Army is looking like it has raised the bar now
I like the insides - looks like it would need very little tweaking at all tbh
Though G&G receivers & their bucking are second to none
End of the day - any one will do ya proud
it is not so much the gun but the player who kicks ar$e
(or gets his ar$e kicked by that 12 year old kid with that JBBG special plinker in my case)