Looking for some clarity in case I am reading this incorrectly. I was reading the description for Semi-Automatic firing mode in SR5, page 178, and noticed this line:



Does this mean you can only perform just one semi-auto fire with a single semi-automatic weapon in a given Action Phase, or would I still be able to fire two semi-auto rounds, taking two Simple Actions, just as it was in SR4A?

it means you can only fire one single shot per action phase.

note that this is actually different from single shot in that you can now do a "semi-automatic burst", which is what you should use to represent shooting twice in the same action phase. single shot doesn't have that option.

So a character cannot combine even a semi-automatic fire with any Attack action in the same Action Phase, not even throwing a grenade, what would a character do with the second Simple Action?

Aim?

I have a question about a related subject; the MGL-12 is a SA grenade launcher, how would you handle a Semi-Auto burst with this? Roll for deviation with all three grenades?

Characters only get one attack action per action phase no matter what in SR5, unless they split their dice pool. The extra simple can be used to aim, take cover, or some other strategic action.

I can't think of any interpretation of the rules that wouldn't either be useless (-2 to dodge) or overpowered (3 different/combined explosions).

Maybe reduce the damage-falloff? (That would probably be my go-to rule if I ever encouter such a situation.)
Or reduce the target number to prevent scatter?

Actually (for a change) the War! rules for multiple grenades are not that bad: Roll for grenade scatter normally for each grenade. Take the highest explosive force, this will be base DV and add 1/2 explosive force for every other grenade... chunky salsa rule still applies for rebounding shock-waves.

That's still too much. I'd mean a base DV of 36 on AP-grenades, undodgeable to boot. That's over 50% more than a 2000¥-frag-rocket and instant death to anything in about a 15m-radius.

Almost forgot: Chunky-Salse is utter crap (from a realistic as well as a gaming point of view).

Depends on how you play it. Keeping an explosion contained is tough but very deadly if you can do it!

So.. How many angles do you count for rebounding purposes? Two for each dimension (i.e. left, right, front, back , up, down)? Will a grenade packed into a block of cement reach the power of a nuke? Do frag-grenades use rubber-fragments? (Because they obviously have more rebounding power than an explosive grenade.)

Again... it depends on what is around you. That first blast travels to the first barrier, loosing dmg if it travels far enough. When it reaches the first barrier, you check the dmg of the blast against the barrier by rolling a structure + armor of the barrier. If the barrier fails to beat the dmg of the blast, and the damage is higher than the structure rating of the barrier, the blast goes through the barrier and no bounce. However, if the damage is contained then it is reflected and reduced for distance (remember a frag looses 1 point/meter and a high explosive looses 2 points/meter) until it reached another barrier where you start over.

Your scenario of a grenade (assuming an HE one) being inside a block of cement: Cement is listed as a Heavy Structural material (pg 197) and has a structure of 12 and armor of 20. HE grenade has dmg of 16P and a blast of -2/m. We will assume that the cement is 1 sq meter (1m x 1m) and 10 cm thick. The grenade goes off. 16P of dmg on all 6 walls so we check each separately. Roll 32 dice and count the hits (avg of about 11 hits). Subtract the hits from the damage and we have a damage code of 5, so it fills 5 boxes of damage per wall (on average) leaving 7 left. The wave did not break through, so it reflects to the opposite wall. The blase has also traveled over a meter so it looses 2 points of damage, and when it hits the opposite wall it has a dmg of 14. Again roll the walls structure + armor and again using the average we have 11 hits so the wall takes 3 more boxes of damage. This will continue until the blast is 0. Now you add an item to the center of the box and it will take the 16 , 14, 12, 10, 8, 6, 4, 2 dmg every reflection or a total of 16+(14*6)+(12*6)+(10*6)+(8*6)+(6*6)+(4*6)+(2*6) = 352 points total.

So again, containing an explosion is difficult but when you do, it is deadly!!

First: Sorry for derailing the topic.

Second: On to the chunky-salsa business...

So, you counted the 6 basic directions (fair choice). How about multi-facetted barriers, say an Icosahedron (just to demonstrate the point).
Also if you count 'down' as one of the angles of reflection, wouldn't most grenades (since they usually go off while lying on the floor) do double their listed damage?
Also this looks like far too much roll-play to me (and I haven't even started with the physical/realistic side of things).

Well, since the avg person with a body of 3 and armor of 15 are looking at on avg 6 hits on the dmg test, they take 10 pts on the initial blast and are pretty much gone there, why even roll-play it out past the first bounce?? The key is never get caught in a secure room with a grenade. Normal building materials will have the blast punch through all the walls on first contact so nothing to worry about.

Normal building-walls, floors and ceilings are usually strong enough to reflect a grenade-blast or two (Strucutural or Heavy Structural Material with 26-32 soak-dice and 10-12 structure-points).
Also, do the walls resist every single blast or do they get 'chunky-salsaed'?
What if I don't take the usual 90° increments to calculate rebounds but 45°, 30° or 15°? Suddenly the blast gets even stronger (and the number of barrier-resist-rolls multiply like crazy (if they meet the armor-threshold)).

It's very deadly, but the rules as written are silly. And it became a lot more so when I watched the corresponding mythbusters episode.
Increasing the DV by a few units in enclosed space would have been faster to resolve and less absurd. Grenades deal more damage in enclosed spaces, yes, but frag grenades don't rise up to the power of tactical nukes. The example written in the book (150+ damage, soaked once) is ridiculous (first, at this damage level, the walls should have disintegrated long ago).

Why? It's only the equivalent of nearly a ton (900kg to be precise) of commercial explosives (Rating 5 x sqrt(900) = 150).

Which is why it should never be a single soak. That makes it more difficult to resolve, to be sure, but on the walls, the damage never really increases beyond the initial blast level, it may be worn away with successive reflections, but the end power through the wall is not the 352 points of damage listed above. It is more like 2 or 4, after punching through the walls. Now, most anything inside is unhappy, to be sure, and is likely dead if the room was a secure room. But MOST walls in a building are not exterior or Support (generally only the outer ones), they are drywall, which will not reflect a grenade all that much.

Pfft, what the hell is that?

That stuff, Made by Aztechnology, that people brush their teeth with, right?

Hmm... instead complaining how about trying to come up with a new rule?

Grenades kill with three effects: shrapnel, blast, heat. The later is only an issue if you're dealing with something big or incendiary. That leaves two mechanism for the kill: shrapnel and blast. Frag grenades (primarily) kill with the former. So called "offensive" grenades the later and are much less lethal in the open... in confined space though they're *very* effective.

Gary's U.S. Infantry Weapons Reference Guide has some nice figures:
http://www.inetres.com/gp/military/infantr...enade/hand.html

Casualty radius for frag grenades is about 15 meters, kill radius is 5 meters.
Casualty radius for offensive grenades is about 2 meters, no kill radius is given.

The offensive grenade is what we often refer to as a high explosive grenade in Shadowrun... given the figures above, it should be obvious that in the open it should actually be a lot less powerful than the common frag. However since it's supposed to be *more* effective in enclosed spaces, the frag grenade obviously shouldn't use the same rules for chunky salsa effects.

Now our "objectives" are:
1. come up with damage and fall-off codes to be in line with the above figures.
2. New chuncky salsa rule, that boost HE grenade damage into the lethal range when the enclosed space is reasonably small... the effective mechanism how we should go about this should not be the current "rebounding waves" model by default, but whatever we find to be fast and more or less accurate.

Let's examine current stats:
I'd call a dmg. of at least 6 as casualty (causing a mod of -1, -2 and sending most people 2/3 of the way toward death).
I'd call a dmg. of at least 10 as lethal (since average Joe has a 10 boxes on his condition monitor).

The frag grenade has a dmg. code of 18P(f), falloff at -1/m... meaning it does lethal damage within 8 meters, casualty damage in 12 meters. Not that bad.
The HE grenade has a dmg. code of 16P, falloff at -2/m... meaning it does lethal damage within 6 meters, casualty damage in 10 meters... quite a bit more than "real world" figures, and not that much worse than a frag. Obviously the falloff could be bigger, say -3/m, leading to a lethal radius of 2 meters, casualty radius of 3 meters... better.

Now the "hard" part, the "new" chunky salsa rule... while not giving specific figures is prone for abuse, I think we should go with a more fast and loose mechanism than the current rebounding rules. What I have in mind is some fast and loose rules about the effect of total, 3/4 (corner), 1/2 (tube/between two walls) and partial (only 1 wall) containments. Anyone who's actually familiar with blast-wave mechanics and could give us some pointers?

As explosive grenades are primarily tools to clear out rooms, I propose the following rules for them:
1. Their base falloff is (as proposed by Flaser) -3/m
2. This fallof gets reduced to -2/m if more than 50% of the projected blast area is covered by solid obstacles within 3m. (For example a solid floor and roof, but no walls within 3 meter of the point of detonation (large room, grenade in the middle of it).)
3. This effect is increased to a falloff of -1/m if the covered area within 3m is more than 75%. (For example a small room with solid walls, a grenade going of in a safe or in a medim sized room near a solid wall.)
and last but most importantly:
4. The blast-wave not only hits targets in a direct line of sight to the exploding grenades, but rebounds off of solid objects and may strike targets behind cover.

(Example: An explosive grenade is thrown into a small bathroom and the Bad Guy tries foolishly to hide in the old metal bathtub. While the solid tub would protect him from the fragments sent out by a frag-grenade, the blastwave of the explosive grenade just rebounds from the ceiling and hits the target anyway. Since the room is small and well-built enough, the damage falloff is reduced to a mere -1/m and so almsot all of the explosive force reaches the inside of the tub (effective distance: grenade to ceiling + ceiling to Bad Guy).)

For an object to count as a solid obstacle, its structure rating + armor must exceed the DV of the grenade (using the initial falloff values).

Pro:
-No DV-increase to absurd levels
-Explosive grenades have their own niche where they work better than frags
-The rules can be extended to commercial, foam and plastic-explosives if desired

Con:
-Possible situations where the grenade does more damage when it is further away from the target but closer to confining surfaces
-The percentage of confining surfaces within 3m may be hard to determine and lead to discussions (GM has final say here of course)

That with the commercial explosive in the open... In an enclosed space that could actually contain it, imagine what that damage would be!


Reference 5th paragraph.


Reference pg 157 - 158.

Not so silly after all.

The force of a blastwave falls of with the square of the distance from the explosion (since it's area expands at that rate). When the blast is contained, the blastwaves combine and reach a higher destructive potential than what they had on their own... but what is the maximum force? In the real world the pressure couldn't rise above what the grenade produced in its immediate vicinity. So Skynet's proposal about not stacking DV seems like a good idea.

However, I'm still not "happy" enough about how deadly HE are, since in the real world blast is a nasty effect: As the blastwave goes by, it shakes you to your core, and your ears go ringing... closer in, your eardrums actually *burst*, even closer it's your *lungs*, and your armor doesn't do jackshit (unless you're in a full enclosure, like an IFV/MBT fighting compartment).

We could model this with either an ever falling AP value (not good, because then it'd be possible to survive HE even with a thick-shield), or saying that HE ignores armor and scaling damage to fit the organ bursting qualities alone (and ignoring shrapnel, a minimal amount of which even HE grenades produce).

that actually makes an easy house rule, instead of stacking damage, stack AP modifier to reflect the longer duration of the damage. always decreasing though so a frag grenade can gain -AP instead of always being + armor

Fragmentation-grenades don't rely on their explosive force to deal damage but (primarily) on the sent-out fragments (hence the name). Therefore they shoudn't benefit from the mentioned effect.

(Quick note though: if the target doesn't have armor (AV 0), +armor isn't used.)

Also forgarn's comment also has merit, so stacking DV *does* make sense, as the effect although not raising the power of the blastwaves, increases the exposure time and hence deposited energy in the victim's body... still, I think we shouldn't use the rebound rules, since they can lead to ridiculous results.

forgarn, could you give us any figures on actually how much *worse* enclosed explosions are? (i.e. how high can the damage realistically go).