Recoil for Single-Shot Weapons

[Tomsdad]

Originally Posted by Ulzgoroth

No, that was about reality.

I generally try to use "rcl" rather than "recoil" to refer to the game stat, to avoid conflating the stat named "recoil" with the physical phenomenon of recoil as much as I can.

Ah OK fair enough (and yes a good distinction I think!).

It's just as you say the recoil of photons out of a laser would be so little as to be pretty much negligible*, so I wondered at the point being made.



*assuming a hand held weapons grade laser's firing mechanism works as we imagine it would

[Cheomesh]

Originally Posted by Tomsdad

lasers have a recoil stat of 1 in GURPS because 1 is the lowest* stat you can have, if they had no recoil i.e. Rcl 0 Then you'd hit with your entire RoF on a single success.

You score an extra hit for every multiple of Rcl by which you make your attack roll, up to your RoF. This means Rcl 1 would hit on every number in your MoS, because 1 is a multiple of every number.

Rifle-14 and 3d6 roll of 10 gives you a MoS of 4 - that is 2 total hits on a Rcl 2 weapon, and 4 total hits on a Rcl 1 weapon.

Anyways the real reason single-shot weapons have Rcl is because other weapons have it, and it may be useful to know how the weapon reacts as if it wasn't a single shot piece.

M.

[kdtipa]

Originally Posted by Cheomesh

Rifle-14 and 3d6 roll of 10 gives you a MoS of 4 - that is 2 total hits on a Rcl 2 weapon, and 4 total hits on a Rcl 1 weapon.

Shouldn't that be 3 hits on the Rcl 2 weapon and 5 on the Rcl 1? A hit by 0 margin of success is one hit.

[Cheomesh]

You are absolutely correct; I meant to say EXTRA hits, not TOTAL.

M.

[Tomsdad]

Originally Posted by Cheomesh

You score an extra hit for every multiple of Rcl by which you make your attack roll, up to your RoF. This means Rcl 1 would hit on every number in your MoS, because 1 is a multiple of every number.

Rifle-14 and 3d6 roll of 10 gives you a MoS of 4 - that is 2 total hits on a Rcl 2 weapon, and 4 total hits on a Rcl 1 weapon.

No I know but my point was you have to give Laser Rcl 1 because that's how the system defines no recoil (barring the very rapid fire add on)

So you have a range of stuff that qualifies for Rcl 1 for a variety of reasons. Even if there's actually a range of recoil within that group. As I said if you followed the progression down on Rcl values less than 1 you get more and more hits per MoS until you get all fired shots hitting with Rcl 0 on 0 MoS.

Originally Posted by Cheomesh

Anyways the real reason single-shot weapons have Rcl is because other weapons have it, and it may be useful to know how the weapon reacts as if it wasn't a single shot piece.

M.

True (and as has been stated some weapons with a Rof of 1 can occasionally access higher Rof's)

[swordtart]

Originally Posted by Ulzgoroth

Photons have momentum. It'd be far to little recoil to feel on any remotely realistic setup, but it would be there.

How does a massless wavicle have momentum? If it had a charge, I could have accepted some sort of electo-magnetic explanation but that seems improbable.

In the event of a laser with a high RoF and with no appreciable Recoil (or any other weapon where the Recoil can be mitigated by being 100% locked down, not all weapon barrels vibrate, not all weapon actions cause vibration), I can forsee a situation where you could fire as many shots as you had ROF and you would expect them to either all hit, or all miss. In this case Rcl of 0 wouldn't seem unreasonable.

I can also see a multi-barrel weapon that fired all it's shots simultaneously (volley gun) also having a Rcl of 0 (though the felt recoil could be significant). The RoF is not really an issue for the volley gun as it is effectively a single attack and you can just average up the damage done by each bal (like a shotgun), but there is scope for higher TL weapons for which you can select a number of barrels to fire (and so you would need to have the attack some multiple of a single barrel).

I suppose in these cases you could stick with Rcl 1 and specify a RoF of 1 and abstract out the multi-shot as purely affecting the amount of damage, but this seems a bit artificial.

If Rcl is being used to simulate deviation from the aim point for other non-Recoil reasons e.g. the inherrent instability of a hand held weapon resulting in small deviations from the initial aim point on subsequent shots (flinching, mechanical movements due to trigger pull etc.) then there should be a mechanism to reduce it to 0 with special equipment (a locked down bench rest or a tripod for example). For heavy Recoil weapons like heavy MGs you may not be able to wholly eliminate the wobble, but for low Recoil weapons you should be able to remove it entirely and get Rcl down to 0.

[Varyon]

Originally Posted by swordtart

How does a massless wavicle have momentum? If it had a charge, I could have accepted some sort of electo-magnetic explanation but that seems improbable.

Part of a photon's particle character is that it has momentum. Lightsails, for example, make use of this property to "generate" thrust (they basically just catch photons, and the transfer of momentum slooooowly pushes the spaceship forward).

Originally Posted by swordtart

In the event of a laser with a high RoF and with no appreciable Recoil (or any other weapon where the Recoil can be mitigated by being 100% locked down, not all weapon barrels vibrate, not all weapon actions cause vibration), I can forsee a situation where you could fire as many shots as you had ROF and you would expect them to either all hit, or all miss. In this case Rcl of 0 wouldn't seem unreasonable.

GURPS Rcl has... issues. This have been explored quite a bit on these forums. Here's my take on it, although that system needs some work to be more gameable.

Originally Posted by swordtart

If Rcl is being used to simulate deviation from the aim point for other non-Recoil reasons e.g. the inherrent instability of a hand held weapon resulting in small deviations from the initial aim point on subsequent shots (flinching, mechanical movements due to trigger pull etc.) then there should be a mechanism to reduce it to 0 with special equipment (a locked down bench rest or a tripod for example). For heavy Recoil weapons like heavy MGs you may not be able to wholly eliminate the wobble, but for low Recoil weapons you should be able to remove it entirely and get Rcl down to 0.

GURPS Rcl is more akin to the Spread stat from my linked system - it's meant to represent the inherent spread of bullets as the weapon is being fired, regardless of how stable the firing platform is (a more stable firing platform just means higher skill). At least, that's how I interpret it. Actual recoil has more of an impact on MinST than it has on Rcl.

[Ulzgoroth]

Originally Posted by swordtart

How does a massless wavicle have momentum? If it had a charge, I could have accepted some sort of electo-magnetic explanation but that seems improbable.

The short answer without room for me to overreach my knowledge is 'relativity'.

To expand on that a bit, I'd suggest that rest mass is more meaningless than it is zero for something which is moving at c in all reference frames.

In any case, light most definitely does have momentum. You can verify this easily by searching on the subject.

Originally Posted by swordtart

In the event of a laser with a high RoF and with no appreciable Recoil (or any other weapon where the Recoil can be mitigated by being 100% locked down, not all weapon barrels vibrate, not all weapon actions cause vibration), I can forsee a situation where you could fire as many shots as you had ROF and you would expect them to either all hit, or all miss. In this case Rcl of 0 wouldn't seem unreasonable.

Actually, you probably couldn't, because firing at full RoF means firing for the entire second, and hitting with all shots means keeping the gun on target for the entire second, or at least for all the moments when the gun is actually firing across that period. That is far from trivial. (Though with the stats for lasers it's also far from impossible.)

Originally Posted by swordtart

I can also see a multi-barrel weapon that fired all it's shots simultaneously (volley gun) also having a Rcl of 0 (though the felt recoil could be significant). The RoF is not really an issue for the volley gun as it is effectively a single attack and you can just average up the damage done by each bal (like a shotgun), but there is scope for higher TL weapons for which you can select a number of barrels to fire (and so you would need to have the attack some multiple of a single barrel).

It is just like a shotgun, and like a shotgun it has Rcl 1, not 0.

Originally Posted by swordtart

I suppose in these cases you could stick with Rcl 1 and specify a RoF of 1 and abstract out the multi-shot as purely affecting the amount of damage, but this seems a bit artificial.

If, for some baffling reason, you stuck with an RoF of 1, the value you selected for rcl would be irrelevant. (See the original topic of the thread...)

But this is the way to model something where you either hit with it all or miss with it all, yes. Multiply damage by N and add a (1/N) armor divisor. A side effect is that you get no RoF bonus, which actually makes sense...

Originally Posted by swordtart

If Rcl is being used to simulate deviation from the aim point for other non-Recoil reasons e.g. the inherrent instability of a hand held weapon resulting in small deviations from the initial aim point on subsequent shots (flinching, mechanical movements due to trigger pull etc.) then there should be a mechanism to reduce it to 0 with special equipment (a locked down bench rest or a tripod for example). For heavy Recoil weapons like heavy MGs you may not be able to wholly eliminate the wobble, but for low Recoil weapons you should be able to remove it entirely and get Rcl down to 0.

The GURPS 4e autofire rules are not a good model. They're really, really not a good model. The best (and to some people this is really important) that might be said is that they produce fairly acceptable results for humans shooting personal weapons at humans, and their errors when pushed usually don't horribly break the game.

So I really don't think arguing from principle that some things ought to have Rcl 0 can go anywhere useful. Rcl 0 isn't an okay value for the system, and things where recoil doesn't apply still get rcl 1 minimum.

[roguebfl]

Ok before this get much further please note the GURPS Rcl stat has almost nothing to do with the "kick" of of a weapon that some times called by the non game term recoil. In GURPS that is deal with the Min ST stat of a weapon. So a low kick weapon like laser has a low Min ST as it easier to hold stated. If you use a weapon who Min ST it too high for you you have trouble holding it steady hace get a peality to hit. But if you strong enough to can control it's kick.

Rcl is about shot grouping. weapons deigned to hive tight grouping has a low Rcl weapons with a wide shot grouping (weapon desgined to sprey) have a high Rcl.

[Anders]

AFAIK, all particles have momentum.