Is there ever occasions where a Tactical Marine should not be using Bolt Weapons? From what I can tell, regular Bolters, Bolt Pistols, and Stalker Bolters are the way to go with Tacticals. What about Plasma guns and pistols? Never?

I'd say it depends on your kill-team, the mission and the abilities of the TacMarne in question.

Presently I am rolling with a Distinguished Imperial Fist TacMarine, going on an high-priority(135 req) mission with my kill-team, behind enemy lines.

We've got a Devastator Marine with absolutely wonderful ballistic skill and hefty weapons.

We've got a Tech Marine with a heavy-bolter.

We've got an Apothecary with a meltaweapon.

And we've got the galaxy's most spinny, killy, Assault Marine.

Enter my TacMarine. He's not a particularly good shot, having a BS in the 30's. His WS is around 60 and he has decent Toughness and Strength.

A good TacMarine supplements his kill-team, making up for the weaknesses of the more specialized brothers in the team. We've got -alot- of bolterfire coming out of our Devastator and Techie, and our Assault and Apothecary will wreck any single target in melee. So I opted to go with short-medium range crowd control instead of raw damage.

I've kitted out my TacMarine with a balefire gun, a stormshield and a Thunderhammer, plus a signum link(which we all have, except our squadleader, who's got a signum, naturally). I take it upon myself to be in the front as often as possible, ensuring I am the first to engage.

"The tactical marines shall draw the fire"

And this is what I do, making myself a target and then taking cover, allowing our devastator to set up behind me. If the enemy advance to shut down the Devastator, they get coated in radioactive prometheum from my balefire gun, and should they close the distance further, our Assault Marine swoops in to assist me in Melee, him with lightningclaws, myself with Thunderhammer.

Just an example

Make up for the weaknesses in your kill.-team. This is the duty of the Tactical Marine. The weapon you chose should be one that benefits whatever role you take upon yourself in that mission

it depend of the needing….

I play a wolf tac marine, and I like to use my bolter (kraken), and take always a chainsword I'm a son of Russ….

but if the situation gone bad, i can take any other weapons, i can substitute the assault with a power axe and a plasma pistol….

I can take the heavy bolter or missile launcher to help the dev….also a lascannon or plasma cannon…to inflict heavy damage

I can use flamers for area denial…

so, with a tactical, you can substitute any of the other class….

hope this help

My Lamenter tac marine got quite fond of a combination of chainsword and assault shotgun.

My crusade-era Alpha Legion tac marine usually stuck to the bolters - and plotting.

I've been conflicted about this too.

Because versatility is the name of the game for the TacMarine, it's hard to argue with the Bolt Gun, or maybe a combi-weapon. On the other hand, a plasma gun has a good degree of versatility as well (firing modes, etc.).

As others have said, it depends on the nature of your kill team and how you fit into it. In our group, we some strong melee fighters. As a result, the bulk of the ranged attacking is taken up by my tactical marine (and the devastator, of course). However, I'm also the leader on most missions and I like to drop onto a world with a pretty iconic look: the bolt gun is hard to beat for that 'classic' look.

I like to leave the Signature Wargear stuff to the others and just trust in my bolter. I can always requisition on a case by case basis (most of the time, I grab a missile launcher and a back banner and call it a day)

I'm very much of the opinion that tactical marines should be flexible, and that includes being able to use multiple different types of weapon.

Our Deathwatch group (which doesn't play very often, so my experience is limited) tends to pass weapons around a lot, so for example we'll usually have a heavy flamer just on the offchance that it's useful for one of us to be carrying a heavy flamer. The tactical marine is an obvious choice to switch to whatever weapon is most appropriate for the current enemy.