I have a G&G R8L and was really surprised by the long range accuracy as a completely stock sub-£200 AEG. Most of my engagements happen around the 50-80ft mark, with some long range shots up to 150, although they are more suppression than anything else and not meant to be particularly spot on target.
I use Blaster Bio 0.25 and Devil Blaster 0.25s, I can expect groupings to all fit on a portrait A4 sheet at 60ft, and possible the odd one outside that at 80ft if there's a bit of wind. There's more vertical deviation than horizontal, but I expect an aftermarket hop up upgrade can help dial that in. I'm considering putting a tightbore in as well, since that would also push the .20g fps a bit closer to 350, which means I could think about going up to 0.28s without the need for spring changes, because as I'm led to believe, with spring changes - especially on a more budget than pro gun - it's usually wise to also upgrade other internals for protection from the harder strength.