I use .28s in all my 350fps and lower guns, and suffer no loss in range over the full auto queens out there.
I also use .4s in my 350fps M14 SOC16 DMR and it sends them just as far as any other gun shooting a .2..... they just take longer to get there is all :shrug: but when they do arrive its not like getting tickled by a nat that no one notices, its like get hit by a nat swinging a cricket bat :tup:
But like Woogie said on the previous page, your going to have to totaly re-think the mods in your gun to achieve it, as sadly its not a case of screwing bits together and getting results, you'll also need to put in a little DIY effort aswell :nuts:
A long(ER style) hop nub and LRB are essential to achieving long range and accuracy with limited fps.
Try adding some weight to your piston, about half an ounce is enough, this will actualy reduce your fps with a .2 (so you can boost your fps a little to regain what is lost) but with all things remaining equal you will gain fps with heavier ammo. You will have to fit some form of buffer on the cylinder head to help with impacts.
You will also loose fps from having to increase the hop pressure to lift a heavy BB, so again you can boost your spring to compinsate for that lose.
Bore out your nozzle to its maximum, if your using a VSR 5.5 is about as far as you can go with this, then deep port your cylinder head, I dont mean the simple rounding out that you see on the DIY threads, I mean properly air flowing and polishing it, to get as much air out as fast as possible.
There are other things such as nozzle length vs nub depth vs BB positioning to consider aswell, that have a profound affect on BB lift and accurcy, but they are way to complicated and overwhelming to cover here right now :nuts: