I've worked this out in terms of mass vs. recoil in several previous threads here on Dumpshock. Do a seach for "trolls and guns" by user "Raygun", category "Shadowrun", date "any date". You'll find 'em.

Basically, a .50 BMG rifle platform that a Troll could conceivably walk around with works out to the equivalent of a human with a 5.56x45mm rifle (what most armies issue infantry these days).

This goes back to trolls being made of meat. A ton of meat will absorb the recoil but the point the rifle stock hits the meat is going to be pounded into bloody hamburger once you've burned through a belt of ammo. Trolls' dermal armor helps a bit but I suspect anything short of a rhino will get bruised from the recoil of a .50BMG in autofire.

Give the troll a decent harness that distributes the force over a wide area and you've got something other than a bruised, bloodied, and tenderized troll.

I think the big thing is that if you let a troll treat a weapon as "light" that the uncompensated recoil is not doubled. Which kind of makes sense as the weight of a troll's arm on the forward grip will provide a lot more recoil-resisting inertia than even Arnold Schwarzenneger's. IIRC, shotguns count as "heavy" weapons and I'd have no trouble with trolls considering them "light."

I think i'll just 'port the table over for now and see how that works for a while.
Report back in a few weeks.

Edit: The SR3 from CC one, not the broken SR2 one from FOF.

Or rules that trolls are easier to hit?

After all, if trolls get additional boni because they are big, there should be additional mali because they are, well, big...

Again, the recoil impulse on something like an M82 is described as being similar to that of a 12-gauge magnum shotgun. People fire those all the time. We don't have any real problem in Shadowrun giving human characters fully-automatic shotguns (asides from the fact that they have a hard time hitting anything)... why would there be a serious problem giving a noticeably heavier (and similarly-recoiling) weapon to someone who weighs 3x as much?

I am made of meat. So is my little brother's girlfriend. The fact that I am double her weight (I'm 215 pounds) is one of the reasons that I'm able to run through several boxes of 12-gauge ammunition in a 12-gauge pump shotgun without really noticing, and she's not willing to get knocked around by more than 3-4 shots.

I recall helping my father (a man who grew up shooting, who's shorter than I am but built heavier) sight in a bolt-action .338 Win Mag a few years ago. After 50 rounds at the range, we went home and he took off his shirt to see why his shoulder hurt so much. He had a hematoma forming on his shoulder from the recoil. A few weeks later, he took it out again to test the new recoil pad he'd installed on the (bare wood) butt of the rifle to try and cut down on the abuse he was taking from it, and had absolutely no problems with it.

.50 caliber weapons like the M2HB are intended to be fired from tripods or vehicular mounts. They don't have a lot in the way of ergonomics or recoil handling... they're built to be able to provide a fairly sustained rate of fire and not overheat as much. Given proper furniture, muzzle braking, buffering, and weapon layout, putting together a .50 caliber, select-fire battle rifle for trolls would be quite doable, and I imagine they'd be able to handle them in much the same way that normal humans handle .30 caliber rifles of the same type.

I think I will design just such a rifle once Arsenal is released. Maybe I'll make a mock-up with the CC rules.

I concur. When I was a little kid, my grandfather gave me a box of .50 BMG duds. Maybe 30 fit into the shoebox. That's why God invented belted ammo.

Hence the Complex Action to load a belted weapon, as opposed to a box mag, which is a Simple. Do you suggest two Complex for belted?

And you obviously failed to read the threads I suggested that you search. The Troll, being a much stronger, more massive animal, would be able to support the use of a weapon that is much heavier than one an average human would be able to effectively wield. The mass of the weapon itself absorbs the "excess" recoil and all is well.

Again, a Troll would likely have very little issue handling a 70-90 pound .50 BMG machine gun as a human handles a 7-9 pound M4/M16.

He needs only a weapon that is suited to his stature. Otherwise, he needs smaller hands. Scale up. It's not rocket science.

I would agree, so long as the troll has no issues interfacing with the weapon.

What current weapon counts as an "MMG" in this context, then? I know that can't include GPMGs like M60s, M240s or PKMs, because all of those can be fired from the shoulder just fine (if slightly inaccurately, thanks to poor ergonomics and relatively stiff recoil) by a human. I can't really think of any modern non-heavy machine guns that aren't designed so that they can be fired from the standing unsupported position by a human -- at least by relatively strong guys.

Firing an actual HMG without any support might be a bit punishing for a human, though that's difficult to test because current HMGs don't exactly allow a human to fire them from the shoulder (no stock and poor grips make it difficult for a human to carry those 30+kg pieces of steel, let alone fire them accurately without support, even ignoring recoil). Firing .50 BMG rifles from the shoulder is, as others have mentioned in this thread, similar to firing a 12G with rather hot loads. This guy (Realplayer video) doesn't seem "concussed" as he fires the M95 .50 BMG bolt action rifle from the shoulder.

Again, with the mass ratio, I think if the MMG or even HMG were modified for troll-appropriate ergonomics, I see no reason why a troll couldn't use the weapon. Maybe a weapon redesigned from the ground-up as a troll-specific hand-held weapon. So perhaps the canon weapons from the book wouldn't be appropriate (being designed to be fired from a stable platform, meaning not a platform made of meat), as they're bulky and clumsy. But a properly designed weapon should not experience an issue in a suitably large, suitable strong troll.

If you must know I am a parital expert on this matter.

I have been trained on a wide range of firearms (ranging from pistols to MMGs). I know how they fire, I know how they work, I know what is feasible and not when firing these weapons.

The traditional description of an MMG does not include any caliber requirement, it just needs to be a machine gun capable of extended firing (generally speaking, a heavy quick-change barrel) and being fired from both tripods or other heavy mounts and from bipods. Nearly all modern MMGs are chambered for 7.62x51mm NATO or 7.62x54mmR, however. These days it is more common to talk about General Purpose Machine Guns, like the M240, which can be used with vehicle mounts (often with some modifications), tripods, bipods, or fired without support.

"Kick of a shotgun" has quite a bit of leeway, of course, but going with a low-end 12G shot load:
437.5 grains at 1200fps with 40 grains of propellant from a 7.25lb Remington 870 = 16.2ft-lbs of recoil energy at 12fps, recoil impulse of 3.04lb/s
Versus standard M80 ball from an M240B GPMG:
146 grains at 2750fps with 46 grains of propellant from a 24.2lb gun = 5.1 foot-pounds of recoil energy at 3.7fps, 2.6lb/s of recoil impulse.
And that's without taking into account the reduction of felt recoil from a gas-operated automatic weapon. Of course the heavy bolt and the rest of the internals going back and forth, as well as the belt being pulled across the weapon, cause the gun to shake a fair bit, but the actual recoil per shot fired should not be anywhere near as bad as that from most shotguns.

Such devices are not quite equivalent to shoulder stocks on small arms, and would be useless (or worse) when firing the weapon without support.

I don't really disagree about the damage code, but why could a HMG not include SA and/or BF firing modes?

Absolutely right. M60-series machine guns fire the 7.62x51mm NATO round, which is an order of magnitude weaker (almost literally ) than the .50 BMG/12.7x99mm round fired by the M2HB HMG.

All very interesting, but fairly moot, as we're discussing the utilisation of weapons made with advanced technology in 2070 by a group of humanoids standing 2 to 3 metres tall and weighing upwards of 200kg

While there is a certain amount of subjectivity on the matter of felt recoil, I thought I could share some personal experience here.

My DSA FAL carbine weighs about 10-11 pounds loaded and scoped, noticeably under the weight of most MMGs (about 25 pounds). It's chambered in 7.62x51mm/.308 Winchester, the same round most of us agree is a good benchmark for defining an MMG. My Mossberg M500A is a 12 gauge, and can take 3" shells. While the FAL's recoil is kind of sharp, it doesn't hit nearly as hard as the Mossberg does loading a 3" 00 shell, even when fired with the gas action closed off (which essentially turns the rifle into a straight-pull bolt-action). I doubt that a weapon chambered for the same caliber but weighing twice as much as my FAL is going to kick more.

I think you may be confusing the M60 with the M249. The M60 is referred to as a General Purpose Machine Gun (a type of MMG meant to be usable both as a man-carried weapon and as a vehicularly-mounted weapon), and fires 7.62x51mm. The M249 is a Squad Automatic Weapon (a term that almost always indicates an LMG), and is chambered for 5.56x45mm.

What's your background? I'm always interested in seeing how different groups are trained and what they're taught.

Lucky me for not having a real choice in the matter.

awwww

*pats Austere Emancipator*