When my previous group and I got a hold of the Dark Heresy rulebook (practically the day it came out), we were all pretty satisfied with the rules, with the exception of one. We noticed that the rules state you are not allowed to repeat the same half action twice in one round.
A round was described as being a 5 second time period. This, in effect, meant a revolver or shotgun could fire one shot in five seconds. Not only that, after firing that shot, you had a half action leftover which could not be used to just pull the trigger again, often forcing a character into doing... nothing. Having just moved over from the Mechwarrior RPG, this seemed odd (in the Mechwarrior RPG, it was quite easy to empty a 30-round magazine on a target in one round).
So we just decided to say screw it and modified the rule to say that non-movement half actions could be repeated. Then we noticed that semi-auto fire was a Full Action. I don't know about you, but my 'stub automatic' fires a bit faster if I ask it to, so we switched semi-auto fire to a half-action as well, allowing for a single player turn to have action sequences such as two single shots, two melee attacks, and two semi-auto bursts.
It seemed to have the following effects.
- PCs and NPCs became more able to hit and kill targets during their turn with firearms and melee attacks
- PCs and NPCs burn through ammo faster, making ammo-conservation a larger issue and reloading in combat happens more often
- Basic firearms (lasguns, lascarbines, laspistols, etc...) become far more effective, as even a weak enemy with a lasgun or lastpistol was capable of firing six lasgun shots in a single round
- Everybody goes down quicker and easier, as the volume of fire going back and forth is much higher
- Full auto weapons seemed to stay at their current power level, but they were still effective
In other words, it seemed to change the balance of play quite a bit. Firearms capable of semi-auto became very useful. Firearms capable of only single shots also became powerful, as now you were able to dump two rounds downrange in a round. To make up for this, more enemies had to be thrown at the PCs, but this increased the volume of fire by a lot, which made it possible for a gunfight to go downhill very quickly with a few bad rounds. It also seemed to take some of the wind out of the sails of melee characters and enemies, but I'm not actually sure if I think that is good or bad considering how powerful it was before. We usually made up for this by adding more melee enemies. All said and done, the fights became extremely tense sequences where every move counted and consequences (and bad luck) piled up quickly. I did notice that some weapons are extremely powerful with multiple shots in a round, such as plasma and melta weapons.
Are there any other unforseen consequences I'm not seeing here?
After getting some answers here and on the FFG house-rules board, and in thinking about what has been pointed out, I think I am going to change the way we've been doing things. I'm planning on introducing two new attack options - Semi-Auto Burst, and Full-Auto Burst.
Semi-Auto Burst behaves exactly as semi-auto fire, but does not gain the 10% bonus on the attack roll. In addition, Semi-Auto Burst is a Half-Action. In the hands of a trained operator, this is a very efficient means of firing.
Full-Auto Burst behaves exactly as full-auto fire, but does not gain the 20% bonus on the attack roll and only gets a single hit per 2 MoS instead of a hit per 1 MoS. In addition, Full-Auto Burst is a Half-Action. It's good for wasting ammo for most people, but can be deadly in the hands of a trained operator.
The following half-actions may be used twice in a single round: Ranged Attack, Semi-Auto Burst, and Full-Auto Burst.
I believe by instead of expanding all half-actions to be 'repeatable' and just naming these three half-actions, it will have the desired effect on the way combat plays out without a lot of the nasty side effects that have been pointed out. Also, limiting these to exactly twice in one round prevents characters who somehow gain an extra action (if I recall correctly, some psyker powers can do this) from repeating it a third time, firing weapons faster than they mechanically are capable of.
The reason I introduced a full-auto half action is because some weapons have a full-auto rate of fire that is less than twice the semi-auto rate of fire. Also, I like the idea of people wasting ammo with pray and spray to little effect. :)
Thanks for the input guys. Will try out the new rules and see how it goes. I don't think it will cause too many drastic changes, as I have sat and watched a guy in carapace armor take 15 lasgun hits in a single round and lose 4 points of health. Having said that, it is very possible that the Full-Auto Burst option will not be hanging around for long when scummers with Autoguns decimate the party. :)