[Skruface]

You don't want 30 RPS in a support weapon unless you intend to go through several bags of bb's per day. Remember, as a SAW gunner, your role is to suppress the enemy with high volumes of fire to allow your companions the freedom of movement to outflank and eliminate the enemy while their heads are down. Having a slower (but constant) barrage of fire will be most effective in keeping their heads down. You also don't need a tightbore barrel - you want a wider spread of fire, not pinpoint accuracy.

I built my RPK as follows a few years ago; never had any problems with it:

TM AK47 based:

TM AK47 gas tube + front sight + Dust cover + Stock Tang
TM hopup unit with Madbull 6.03 Black Python II 590mm inner barrel, Systema hopup rubber and (recently added SCS hopup nub)
King Arms AK74 receiver + front sight block
Real Steel RPK rear sight
Real Russian PK-A red dot sight on side mount
BattleAxe Steel + Wood RPK kit (same one that Styrak sells)


Gearbox:
MODIFY TorqueUp gears + anti reversal latch (old style, not SMOOTH; if re-building I would go SMOOTH)
G&P M140 motor
TM trigger block with custom wiring for MOSFET
Triggermaster MKIII mosfet
MODIFY S100 spring
Guarder steel bearing spring guide
Custom ported TM piston head on modified TM piston (2nd last tooth removed)
Guarder Stainless non-ported cylinder
Guarder Stainless Steel cylinder head with ARS Sorbo Pad
TM tappet plate + selector plate
11.1v 4400Mah 20C LiPo (ROF/Motor Speed controlled by Triggermaster MOSFET)