You make it seem like i have never played airsoft before. i just dont have amazing knowledge of whats going on in my guns.
I think this is the part you need to remedy first.
Buy a 2nd hand AEG that's fit for the knackers yard and open it up and tinker with it.
Change the hop chamber. Change the rubber.
Open it up and take the gears out.
Change the spring. Change it from front wired to rear etc.
Even better - buy an absolutely knackered sniper
rifle and learn to do it up.
Like buying an old fiesta to learn about cars, or cutting open a dead body to learn surgical procedures.
The reality of your situation is you're wanting maximum performance from your gun with minimum effort.
No Stock-out-of-the-box sniper
rifle is going to give you anywhere near the level of performance that you're dreaming of when you're imagining yourself getting headshots from a prone position from 80 metres.
Like PT said, you're going to take your box fresh sniper
rifle to a game and get utterly out matched and out ranged by nearly every other gun.
You'll then realise sniping isn't as easy or cool as it is in the Videogames one of two things will happen:
You'll either upgrade it and continue to tinker with the gun and practicing.
Or more likely, it'll be another
yet another Well MB01 up for sale in the classifieds section within a month because the reality didn't match the dream.
I know the above sounds harsh, but this is the reality.
Unless you buy a pre-upgraded rifle from bespoke airsoft or ASPUK.
http
://www.bespokeairsoft.co.uk
https://www.airsoftsniperparts.com/sniper-rifles
Or buy a 2nd hand one that's already done up. Then all that is left to do is learn to snipe.