So, the underslung part of the Combi-weapons change their profile to S/-/- and 1 shot per clip. This means that, for example, the one-shot plasmagun would need 4 full actions to reload. For one shot. That seems... a bit much. Any one of the combi-weapons has a shorter reload time on the bolter-part than the combi- part. Given, care should be taken when reloading the volatile weapons as opposed to slamming in a new clip, but it's a one-shot, it can't be that large or take that long... unless it can. I don't know, I've never used a plasmagun in real life, it might be really hard to screw in the plasma canister.

Plasma weapons use two canisters of fuel as ammo. To reload a plasma weapon you must first unscrew the already installed canisters in the weapon then screw in the replacement canisters. Following and/or reciting the rites of reloading if your character cares about such things.

Even for a single shot this takes a lot of time.

Combi weapons give you an additional combat ability. Even if they are one shot the ability to deal more damage against a heavily armoured opponent, flame a massive horde, or put a hole in the side of tank without having to take time switching weapons is still very nice.

Side note: in my games I play it as readying or putting awasy a basic weapon for a SM as a free action, but putting away a basic weapon then pulling another out (2 ready actions) is a half action. Dipole maglocks, gun straps, dropping the weapon, and arm mountings of course make it so the action of putting away the weapon is so trivial that pulling out the second weapon is still a free action.

Except for the Combi-Melta Combi-Weapons are extremley broken even with the optional weapon stats.

Combi-Weapons should have one third their original payload and the original ROF. This isn't with the fluff but after the nerfed Bolters who cares!

No one in our Group has ever requistitioned a Combi-Weapon because other weapons like the SB are much more effective and the advantage you get to switch quickly between weapons is pretty useless even with houserules because hard targets like Tanks are rarley able to suprise a SM so no need for a sudden switch and by RAW this isn't an issue in the first place.

Kain McDogal said:

It's another one of those times that a basic skill (which wasn't basic in DH) makes it a bit pointless, quick draw in this case.

I'd say, at minimum the combi plasma should have enough for a single maximal shot (4 irc, could easily be wrong).

But a third doesn't sound too bad (not that i've done the maths).