The SR-05 has "aimed, burst, wild" rate of fire. It has a payload of either 15 or 40 depending on which size clip you use.
One thing that remained consistent from RMB>RCB or with HU is that short bursts always used 20% payload, always got x2 damage, always cost 1 attack
HU2p75 has variable multipliers depending on payload when using long bursts:
- x2 if 15 or less rounds
? if 16-29 rounds
x5 if 30-50 rounds
So it seems like the way it would work is:
- 3D6x2 by firing 7.5/15 rounds
3D6x5 by firing 20/40 rounds
Full (entire magazines) had variation too:
- 3D6x5 by firing 15/15 rounds
3D6x10 by firing 40/40 rounds
Rifts was originally better than HU2 since it had x5/x10 for long/full regardless of payload.
After the reduction to x3/x7 in the conversion book, the x5/x10 become accessible if using the 40-round clip I would assume, if playing by HU2 rules.
HU2 rules have a weird note about taking 3 attacks, but the asterisk explains this is for semi-automatic weapons (2 attacks long 3 attacks full) so it might be written for that. It's weirdly inconsistent though since 2 attacks isn't listed for long burst. I'm assume sub-machineguns are full-auto not semi-auto.
It seems like when using the 15-shot clip that Rifts remains superior to HU for this weapon, since x3/x7 for long/full is superior to x2/x5
Long bursts seem to have no incentive at all for 15 shot clips if using HU2's rules, unless we assume you can't fire short burst at all with them.