My DH group has played about halfway through rank 3, so the characters' identities are well established and my players have a good grasp of DH combat. I bought the Black Crusade rulebook to spice up the campaign's villains and soon noticed some changes to combat mechanics (summarized here for convenience):

• Standard Attacks, Semi- and Full-Auto Bursts all cost one Half Action
• Standard Attacks give +10 to hit, Semi gives +0, and Full Auto gives -10 (extra hits from degrees of success are calculated the same way as in DH)
• Swift Attack is effectively a melee version of Semi-Auto (+0 to WS, extra hit for every 2 additional DOS)
• Lightning Attack is melee Full Auto
• Other minor tweaks (can Suppressing Fire with Semi-Auto for reduced effect, Overwatch simplified, etc)

After some thought, I'm considering porting the BC combat rules into my DH campaign. These rules changes elegantly solve a few niggling problems I've had with DH combat since day one:

• I can't think of a single reason to use semi-auto fire besides "it uses less bullets than full auto!" It seems objectively worse in every possible way.
• If a DH Acolyte takes careful aim and fires a single autogun shot (half aim + standard attack), they have a WORSE chance to hit an enemy than if they just fired as many bullets as possible without taking careful aim (full auto burst).
• How on earth does it take 5 seconds to fire a 6-round burst from an autopistol?

Has anyone tried this in their own gaming group? If so, did it work well? If not, do any of the more experienced DH Gamemasters here have any insights as to how this could affect game balance? Any input is very much appreciated.

I recommend you leave the games self-contained, or devote the time necessary to fully understanding how all the subtle differences of Black Crusade's rules will affect your Dark Heresy game before porting anything. For instance, a few Talents in Black Crusade have been rewritten to engage with the new iteration of Actions, and some Talents now require PCs to spend infamy to be of any use.

Been using it ever since BC premiered. The alterations you mention can be adopted pretty seamlessly. Just make sure that every Talent that interacts with those rules is either also updated to the BC version (if applicable) or simply that it doesn't stop working due to new rules.

Generally, it's easy enough, and creates a much better playing experience. Definitely give it a go!

Hmm, thank you both for the advice. I looked through both books quite thoroughly over the weekend, and I think I'll give the BC rules a try. If things don't work out well, I'll revert to the DH rules, but the BC combat makes much more sense to me.

I have one other question, this time relating to player satisfaction. One of my players recently retired his first character (a tech-priest) and rolled up a heavy stubber-toting Guardsman. I suspect that he made this change after seeing how devastating fully-automatic weapons were: his tech-priest with semi-auto lascarbine never quite matched up to the damage from the cleric's Armageddon autogun or the assassin's hunting rifle, and in one session the cleric was brought from full health to around -27 in one turn by a pair of autogun-wielding Logician Agents (from Edge of Darkness). Since a heavy stubber only fires on full auto, he has a drastically lower chance of hitting anything using his primary weapon under these new rules.

Morangias, did you have any similar issues when implementing the BC combat rules into your campaign? If so, how did you address them? I'm not even sure if I need to make any further rules changes; even with the new rules the heavy stubber is a beastly gun for my 3rd-rank Acolytes (using the Macharian handbook stats: 1d10+5 dmg, 3 pen, 200 clip).

Under new rules, Full Auto is still superior to other firing modes, as long as the guy using it can generate a target number for his to-hit roll in the ballpark of thirty-something or higher. Don't focus on the overall chance to hit, consider how each time he hits he has a good chance of scoring more than one hit. I once calculated an average and for a guy with BS 41 using single shots means landing 0,51 hit per turn, while using full auto ups that value to 0,64 hit per turn. That means that on average, the full auto guy will hit more often, even if it means not hitting for one turn and then scoring two hits on another.

I did that myself, at least for the shooting and it worked great. Because before that EVERYONE wanted autofire, it was the end all be all. With accurate close behind. Semi auto was completely useless. It also allowed me as a GM to use autofire because had i done so under normal rules I would have slaughtered the PC's.

Under new rules, Full Auto is still superior to other firing modes, as long as the guy using it can generate a target number for his to-hit roll in the ballpark of thirty-something or higher. Don't focus on the overall chance to hit, consider how each time he hits he has a good chance of scoring more than one hit. I once calculated an average and for a guy with BS 41 using single shots means landing 0,51 hit per turn, while using full auto ups that value to 0,64 hit per turn. That means that on average, the full auto guy will hit more often, even if it means not hitting for one turn and then scoring two hits on another.

Thanks for the explanation. The Guardsman has over 40 BS so he shouldn't have much trouble harming mutants in the new rules. In DH combat he often scores 4 or more heavy stubber hits on a single target -- quite enough to kill most humans.

I did that myself, at least for the shooting and it worked great. Because before that EVERYONE wanted autofire, it was the end all be all. With accurate close behind. Semi auto was completely useless. It also allowed me as a GM to use autofire because had i done so under normal rules I would have slaughtered the PC's.

I know the feeling. All the players now own one or more full auto weapons -- even the sniper rifle-wielding assassin carries an autopistol for close combat. And my cleric knows just how nasty it is to be on the receiving end of full auto fire

I've had the same issue - every campaign ever, everyone is toting autopistols and whatever heavy weapon offers autofire.

Mind you, the Guardsman will still be missing more often than under the previous rules, and generally will generate less hits than before - it's just that statistically, those times he does hit should make up for it. I can't stress this enough - remind your player that aiming before shooting full auto is an option, he should use it whenever possible.

How on earth does it take 5 seconds to fire a 6-round burst from an autopistol?

The same as it takes 5 seconds to hit someone with one sword blow.

Abstraction. Consider that the shooter will not only pull the trigger, but do other stuff as well. Looking up from or getting back into cover, aiming (not long enough to receive a greater mechanical benefit), yelling something, signaling their friends ... Free Actions take time, too!

Since a heavy stubber only fires on full auto, he has a drastically lower chance of hitting anything using his primary weapon under these new rules.

Thinking about it, it's a bit weird that the hit chance is independent from how many rounds a weapon actually fires - a gun's "RoF" merely determines the maximum number of hits, but not the average? Maybe there could have been a more realistic way to convey the intention behind this rule ... *ponders*

in our group we use the damage rules for weapons from Black Crusade since they tend to be more balanced.