Help stating a Firearm: The American 180 .22LR SMG

[ericbsmith]

Originally Posted by Tinman

Well, that's exactly the kind of stuff I wanted advice on stating.
Thank you.

No problem. The thing to keep in mind with all I did was mostly just comparison to other similar guns. RoF is just Rounds per Minute / 60, since Rounds per Minute is generally calculated based on continuous fire (which few real world guns can actually sustain due to reloading and barrel over-heating; even water cooled chain fed machine guns will risk overheating after a minute of continuous fire). For weight I just googled the weight of the gun, and hoped the source I found was correct (it looked close enough for me).

Bulk is the only really debatable stat, since it's based on an esoteric combination of weight and barrel length/weapon size; essentially how hard the gun is to conceal.

It's much harder to extrapolate weird or esoteric weapon stats, since there are fewer points of comparison.

[Rupert]

Originally Posted by ericbsmith

No problem. The thing to keep in mind with all I did was mostly just comparison to other similar guns. RoF is just Rounds per Minute / 60, since Rounds per Minute is generally calculated based on continuous fire (which few real world guns can actually sustain due to reloading and barrel over-heating; even water cooled chain fed machine guns will risk overheating after a minute of continuous fire).

Not Vickers guns and close relatives. Their rate of fire in the long term is slowed a little by reloading and mostly by having to change barrels every 15,000 rounds or so due to wear, as long as they have ammo, water, and replacement barrels they can fire indefinitely.

[Fred Brackin]

Originally Posted by Rupert

Not Vickers guns and close relatives. Their rate of fire in the long term is slowed a little by reloading and mostly by having to change barrels every 15,000 rounds or so due to wear, as long as they have ammo, water, and replacement barrels they can fire indefinitely.

....or for about 4 hours. That's a record from WWI.

For what it's worth my pre-Internet memories recall stories of the American 180 (equipped with a laser pointer even bigger than the one from Teminator) beign used to write the firer's name in cursive with one long burst and cutting a VW in half like it was a saw.

If that last sounds improbable it might be but old VWs were much lighter than new ones. Under 2000 lbs.

Anyway, the 180 might work better than usual in long bursts.

[Tinman]

Originally Posted by Fred Brackin

....or for about 4 hours. That's a record from WWI.

For what it's worth my pre-Internet memories recall stories of the American 180 (equipped with a laser pointer even bigger than the one from Teminator) beign used to write the firer's name in cursive with one long burst and cutting a VW in half like it was a saw.

If that last sounds improbable it might be but old VWs were much lighter than new ones. Under 2000 lbs.

Anyway, the 180 might work better than usual in long bursts.

I've heard it's got almost no recoil & is very controllable. (It looks that way in the video.)

I'm going to try & have my gadgeteer for a pulp-era action campaign make one. I hope it will prove effective in combat.

[Juca]

I would give it effective recoil 1 for full auto fire.

[Rupert]

[QUOTE=Fred Brackin;2334307]....or for about 4 hours. That's a record from WWI.
I think the WWI episode was more like 8-10 hours for a battery of 10 guns with no failures. In 1963 when they were going out of service they had a huge pile of ammo that was going to be dumped so they took a Vickers and fired it continuously for a week, aside from breaks to replace the barrel. It was still within operating specs at the end and it had fired millions of rounds. A good cooling system, a modest rate of fire, and a lot of mass lets you make a very reliable gun. Modern GPMGs trade sustained firepower for lighter weight.

For what it's worth my pre-Internet memories recall stories of the American 180 (equipped with a laser pointer even bigger than the one from Teminator) beign used to write the firer's name in cursive with one long burst and cutting a VW in half like it was a saw.

If that last sounds improbable it might be but old VWs were much lighter than new ones. Under 2000 lbs.

Anyway, the 180 might work better than usual in long bursts.

It would, yes - the .22LR isn't very energetic and is low-pressure enough that it's also fairly efficient (for a gun), so unless the barrel is very light it'll heat up relatively slowly.

While in a GURPS write-up it would still have Rcl 2, it's also a calibre that will have very low recoil and be very controllable so writing with it shouldn't be hard with a little practice. A new form of annoying to remove graffiti!

Originally Posted by Juca

I would give it effective recoil 1 for full auto fire.

I wouldn't. It fires fast, but not super fast, and Rcl 1 has potential for problems. Sure, they probably won't show up with 1d+2 pi- damage, but it's still risking opening a can of worms.

[Juca]

Rupert, I said recoil 1 because the kriss vector, which is a .45 submachine gun (with a delayed recoil absortion system, but still seems to have more kick than de 180 .22LR), appeared on one of the GURPS books as having recoil 1.
I think, in the case of the 180 american, that the combination of RoF 20 and a very light cartridge, in a moderatelly heavy gun, can be combined to grant it effective recoil of 1 for long bursts.

[johndallman]

Originally Posted by Juca

Rupert, I said recoil 1 because the kriss vector, which is a .45 submachine gun (with a delayed recoil absortion system, but still seems to have more kick than de 180 .22LR), appeared on one of the GURPS books as having recoil 1.

Was that 3e or 4e? In 4e, Rcl 1 is reserved for beam weapons and the like.

[Juca]

The Kriss Super V is on page 65 of GURPS Tactical Shooting.

[Rupert]

Originally Posted by Juca

Rupert, I said recoil 1 because the kriss vector, which is a .45 submachine gun (with a delayed recoil absortion system, but still seems to have more kick than de 180 .22LR), appeared on one of the GURPS books as having recoil 1.

And that was, in my opinion then and now, a mistake.

If a 10 pound SMG firing .45 ACP gets Rcl 1, even allowing for a flash recoil system, etc., we should be seeing Rcl 1 from .22 LR rifles, and SMGs like the PPSsH-41 with it's 11.7 pound weight and low-recoiling cartridge, and I suspect the FN P90 could also make the case.