It's Called CronusMax.It's a thing you buy where you can run scripts on it.For example no reload No Land Beyond etc.So u can just setup a script when u hold the R2 Button Not to have any recoil and to fire automaticly without pressing it but just holding it(There are also tons of others way to setup like doing doing reload cancel which shoot,sprint,reload cancel ,shoot which allows breaking the game and allowing really fast rate of fire ).There is your awenser : ) Its not lag.