So one of my players has collected a whopping 19 frag grenades, and has taken to throwing several of them at a time. Rules say they are only "single shot" but what are your opinions on it? I may limit him to one per turn as 3 2d10 grenades going off is hard for enemies to beat.

I would allow him to use Two-weapon wielder to throw two with the associated penalties. The Accatran Pattern grenade launcher also offers a semi-automatic option.

I would allow also throwing of multiple grenades according to the rules for throwing objects (p.37) IF they are bound in the bunch. Rules for radius&damage can be adopted from demolition charge rules (p.201).

Aye, he'll just have to live with not being able to throw as far.

I was going to introduce a talent for that, it wouldn't be the most basic manuver that needed a talent. Probably act as a semi auto with reduced range of course. But then Grenadier seems to have lost all meaning and I could't think of where to place it.

Beyond that i'd say double fisting is way forward.

Also, maybe suggest some demoltions usage. A couple can make for a nasty booby trap.

I have a house rule where I allow 1 grenade RaW as a half action and a second grenade as a half action that does not detonate until the start of the throwing player's next turn. It has worked pretty well thus far.

Managing to horde that many grenades might earn him the eye of the commissar (could possibly be a sign of heretic activity)

Throwing a single grenade is an attack option, so he can only throw 1 per turn? i guess throwing 2 counts as a two handed attack and incurs the relevant penalties.

strapping multiples together might be an option. it might incur a slight minus to hit because it would be unwieldy (grenades are shaped for accuracy) and they wouldnt all go off at once, but that wouldnt be a massive difference.

also, having that many grenades wont really unbalance the game: once they're gone their gone haha, just throw more enemies at the PCs

The problem arose when he threw three at a couple SD Storm Troopers, absolutely shredding them apart. While I could certainly turn around and do the same to the PCs, that would ruin my campaign and sour everyone's moods. What I house ruled was that throwing two grenades required the Two Weapon Wielder talent; multiples tied together and thrown as a package or whatever used the same damage system as chained demo charges. That is to say, each additional grenade added 1 blast and 1 damage.

There was a great whining and gnashing of teeth in response to my "nerf" of their new favorite tactic.

The problem arose when he threw three at a couple SD Storm Troopers, absolutely shredding them apart. While I could certainly turn around and do the same to the PCs, that would ruin my campaign and sour everyone's moods. What I house ruled was that throwing two grenades required the Two Weapon Wielder talent; multiples tied together and thrown as a package or whatever used the same damage system as chained demo charges. That is to say, each additional grenade added 1 blast and 1 damage.

There was a great whining and gnashing of teeth in response to my "nerf" of their new favorite tactic.

I'm going to babble pointlessly, for a moment.

Okay, you just said something I might view as dangerous. "While I could certainly turn around and do the same to the PCs, that would ruin my campaign and sour everyone's moods." This is my argument for why some heavy weapons, specifically those that are touted as "tank-busters", don't seem to do the damage that a tank fears; if they did, they'd SPLAT the characters who AREN'T tanks, and end your game. Don't be afraid to do to your players what they think is okay to do, themselves; what works for one side of the equation must work on the other. It might kill them, certainly, and OW characters should maybe expect this end result more than some other games, but if you hold back on sensible, because you more fear the players' deaths than that of your NPC's, it cheapens the game. Unless they are so brilliant as to hae devised a whole new way of fighting, and killed every outside witness to it, what works for them might occur to the other side, and then you have to show players how effective it really was.

I'm certainly not saying "Kill them! Kill them all!", but if you make a house rule, it should be universal. In RT, they like to use Mathhammer to make ship combat more balanced, but that works for the NPC's too. You don't get a special kind of grenade the rest of the universe doesn't. Okay, I'm done babbling, now. This might not have even been an issue for you, but I thought I'd share. If you don't want your party to do something, it can't hurt to remind them that it can also be done to them, and with the same messy results. Have a good one!

multiples tied together and thrown as a package or whatever used the same damage system as chained demo charges. That is to say, each additional grenade added 1 blast and 1 damage.

Each kg of demo-charge add 5 m to blast radius, so if we use a direct analogy, then 1 grenade = +2.5 blast.

The problem arose when he threw three at a couple SD Storm Troopers, absolutely shredding them apart. While I could certainly turn around and do the same to the PCs, that would ruin my campaign and sour everyone's moods. What I house ruled was that throwing two grenades required the Two Weapon Wielder talent; multiples tied together and thrown as a package or whatever used the same damage system as chained demo charges. That is to say, each additional grenade added 1 blast and 1 damage.

There was a great whining and gnashing of teeth in response to my "nerf" of their new favorite tactic.

I'm going to babble pointlessly, for a moment.

Okay, you just said something I might view as dangerous. "While I could certainly turn around and do the same to the PCs, that would ruin my campaign and sour everyone's moods." This is my argument for why some heavy weapons, specifically those that are touted as "tank-busters", don't seem to do the damage that a tank fears; if they did, they'd SPLAT the characters who AREN'T tanks, and end your game. Don't be afraid to do to your players what they think is okay to do, themselves; what works for one side of the equation must work on the other. It might kill them, certainly, and OW characters should maybe expect this end result more than some other games, but if you hold back on sensible, because you more fear the players' deaths than that of your NPC's, it cheapens the game. Unless they are so brilliant as to hae devised a whole new way of fighting, and killed every outside witness to it, what works for them might occur to the other side, and then you have to show players how effective it really was.

I'm certainly not saying "Kill them! Kill them all!", but if you make a house rule, it should be universal. In RT, they like to use Mathhammer to make ship combat more balanced, but that works for the NPC's too. You don't get a special kind of grenade the rest of the universe doesn't. Okay, I'm done babbling, now. This might not have even been an issue for you, but I thought I'd share. If you don't want your party to do something, it can't hurt to remind them that it can also be done to them, and with the same messy results. Have a good one!

We had a similar issue with Suppressing Fire. The PCs would use it, NPCs would use it back, and it would slow down the game to a crawl as everyone would just suppress or be trying to get out of pinning. We've all come to a gentlemanly agreement not to use Suppressing Fire for the time constraint it poses - however, I still may throw that in there if I am feeling devious, or want the fight to be hard.

I don't go out of my way to shield my PCs from dying - they do that well enough on their own. What I want to limit, however, is the massive character turnover rate it brings. I have a campaign with a plot that I want to run, and it is dependent on the characters (mostly) being the ones who met the Big Bad in the beginning. Otherwise, the Joe Schmoe replacements aren't too invested in what is going on.

While I have no qualms about traps or enemies throwing grenades at the PCs, what I don't want to do is character snipe by insta-gibbing half the party with three grenades in one turn. Otherwise, it is open season

multiples tied together and thrown as a package or whatever used the same damage system as chained demo charges. That is to say, each additional grenade added 1 blast and 1 damage.

Each kg of demo-charge add 5 m to blast radius, so if we use a direct analogy, then 1 grenade = +2.5 blast.

2.5 would only be .5 less than a full grenade, and I don't want a whole room being cleared by one player chucking half his stash. I'm doing it more to balance a potentially encounter-ruining tactic rather than stick faithfully with what a demo charge does. After all, if they want that sort of explosive blast, they should be using demo charges in the first place!

On the topic of grenades and demolition charges, what would be the possibilities for rigging up a frag grenade and demolition charge like this?

To combine the explosive power of the demo charge and the ability to throw a grenade?

I would rule that you could then throw the demolition charge like a grenade, with everything that entails. Great if you need to chuck a demo charge, not great if it blows up in your hand. Because of how demo charge failures work, I would potentially make it more likely to go off in the character's hand.

Demo charges get a lot of power in exchange for not being throwable. This is part of why they have a multiple explosions rule and grenades don't. If you make demo packs throwable, I would first of all give them a shorter range profile thanks to lack of aerodynamics and the greater weight. I would additionally make them Unreliable unless the modifications are performed by a techpriest with sufficient induction into the cult mechanicus to alter patterns. Then I may nerf the blast radius, or the stacking effect, or both.

Alternatively, you could balance from an action economy standpoint. If the explosives have to be thrown one turn (perhaps even with Inaccurate) and then detonated the next, then that may be balanced.

Basically, if this could work without complications, then the Admech would've made this standard. So there are probably a dozen complications that render this very difficult to pull off.

On the topic of grenades and demolition charges, what would be the possibilities for rigging up a frag grenade and demolition charge like this?

To combine the explosive power of the demo charge and the ability to throw a grenade?

You mean the Tube Charge on page 115 of Hammer of The Emperor?

Aye, he'll just have to live with not being able to throw as far.

And with the increased blast radius if they are thrown on the same target.

Who needs eyebrows anyway?

I've Let players throw grenades at the same time just added extra difficulty, three or more grenades I half the distance one is able to throw, and of course when the players fumble there throws well.... *Sings* Duck and cover!