All FPS measurements assume .20 gram BB's are being fired.
If you use .25's then if the limit is 400 FPS you should be shooting a little under 360 FPS.
The standard size is a 6mm BB (actually it around 5.9x +/- .0x mm), there is only one other size and it's not too common so don't worry about it (it's 8mm BTW).
Velocity limits depend on the field. Most outdoor fields are 400 FPS but it's a limit not a goal, allow a deviation of +/- 5 FPS or so (you don't want to be shooting 396, 399, 395, then 403 cause then it will be disallowed).
Indoor CQB it's usually 350 MAX but 330 (I believe it corresponds to 1 Joule of work put into the BB) is the usual limit for 80% of indoor CQB fields.
As for the range rule (I assume you mean what distance to mercy at).... It depends but 20-25 feet is probably a safe distance to mercy if you're running a "hot" rifle (400 FPS). If you're only running a 350 FPS rifle 10-15 ft is probably a safe distance.
Sniper Rifles work on different rules and you need to separate sniper rifles and BA rifles.
A "semi automatic" (single shot) sniper rifle can go 425 or 450 (Assuming .20 gr BB) (with an MED of 25-30 ft or so)
A BA (Bolt Action) rifle *can* (but doesn't necessarily have to) go up to 500 FPS (again assuming .20 gr BB) (however your MED might be 30-40 ft and you have to switch to a secondary for engaging at closer distances)
With AEG's you can make it a single shot pseudo-"BA" rifle and the trick is to install a MOSFET that locks it to semi only (no matter what fire setting it's set on) with a 1 second delay between shots.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE
Last edited by L473ncy; December 14th, 2009 at 16:42..