Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 01-28-2023, 04:10 AM   #1
shazz
 
Join Date: Jan 2023
Default What would be the stats for 40mm dragon's breath round?

A dragon's breath round is a thing that can be shot out of a shotgun to produce a cone of incendiary particles. For 12ga the stats are in the sidebar on HT103.

What would be the stats if someone gadgeteers the similar thing for, say, M79 grenade launcher? I'm interested in both "long" and "short" 40mm rounds, if that makes a difference.

Last edited by shazz; 01-28-2023 at 04:21 AM. Reason: typo
shazz is offline   Reply With Quote
Old 01-28-2023, 06:59 AM   #2
johndallman
Night Watchman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: What would be the stats for 40mm dragon's breath round

The burning metal particles are going to be pretty small, there will just be more of them in a 40mm round than a 12-gauge. About 4x as many, given the diameters. So I'd give it the same range, but more damage. 1d-2 for the 12ga is an average of 2 points of damage: 1d damage for an average of 3.5 seems about right.

Depending on the gadgetering, it might take longer to burn out than the 12ga round. I'm unsure that long grenades would do you much good with this, unless the design was quite sophisticated.
johndallman is online now   Reply With Quote
Old 01-28-2023, 07:03 AM   #3
Anaraxes
 
Join Date: Sep 2007
Default Re: What would be the stats for 40mm dragon's breath round

By "the same thing", do you mean flame leaping out of the barrel of the grenade launcher, or an incendiary round?

The M79 has a maximum pressure of 3000 psi. Compare to a 12 ga shotgun at 11,500 or about 45,000 for a 7.62mm rifle. A grenade launcher isn't built to contain and focus an explosion of any magnitude, but rather just enough to propel the actual explosion away from you before it goes off. I couldn't find a spec for the chamber pressure of a Dragon's Breath shell, but only a few notes that they were "low pressure".

Assuming we're talking about using the grenade launcher as a flame thrower, then diameter of the grenade is a bit more than twice that of the shotgun shell, and they (perhaps unsurprisingly) mass around four times as much as a 12-gauge shell. So, you're burning four times as much stuff, but not propelling anything (whether hot gas or bits of magnesium) any further, as there's no more pressure to do the propelling (and maybe less).

I'd just use the same range, double the damage (call it 1D burning, rather than 2D-4), increase the burn time to 6-7 seconds, and call it a day. Dragon's Breath isn't really a weapon, but more of a firework. Looks spectacular, but it's made for looks, not effectiveness for any purpose beyond entertainment.

(Note that a 60mm WP mortar round, HT146, is a 2D burn ex with a 15-yard smoke cloud, and that's carrying something like twice the incendiary material and burning it faster, so 1D still seems in the ballpark. If a player was sufficiently insane, I might let them gadgeteer a WP shotgun round that explodes as it leaves the barrel. But they're only a yard behind the muzzle themselves with their face leading the way, so maybe that's not really what they want...)
Anaraxes is offline   Reply With Quote
Old 01-28-2023, 08:00 AM   #4
shazz
 
Join Date: Jan 2023
Default Re: What would be the stats for 40mm dragon's breath round

Quote:
Originally Posted by Anaraxes View Post
By "the same thing", do you mean flame leaping out of the barrel of the grenade launcher, or an incendiary round?
A flame jet, not a grenade.

Quote:
Originally Posted by Anaraxes View Post
I'd just use the same range...
Thinking of it, could the gadgeteer opt for less range with still 10+ yards wide base to have more spread, quoting a shorter and wider barrel?

Quote:
Originally Posted by Anaraxes View Post
...increase the burn time to 6-7 seconds...
Of which only 1st is the real attack?
shazz is offline   Reply With Quote
Old 01-29-2023, 11:02 AM   #5
Pursuivant
 
Join Date: Apr 2005
Default Re: What would be the stats for 40mm dragon's breath round

Quote:
Originally Posted by shazz View Post
Thinking of it, could the gadgeteer opt for less range with still 10+ yards wide base to have more spread, quoting a shorter and wider barrel?
Not unless the barrel itself flares towards the muzzle. Realistically, shattershot rounds form a sort of loose cylindrical cloud as they leave the gun, with little scatter at practical shooting distances. Take a look at shotgun shot patterns to see for yourself.

The closest a gadgeteer could get is a grenade that bursts a few yards beyond the muzzle, sending secondary munitions downrange in some sort of pattern. Sort of a "claymore mine" round, but incendiary.

Quote:
Originally Posted by shazz View Post
Of which only 1st is the real attack?
Sort of. Dragon's Breath rounds turn a shotgun into a mini-flamethrower which covers the target with burning material. The shooter rolls to hit the target normally, but on a hit burn damage continues for a number of seconds. The more incendiary material, the longer the burn time. Alternately, greater damage for the standard burn time.
Pursuivant is offline   Reply With Quote
Old 01-30-2023, 07:24 AM   #6
shazz
 
Join Date: Jan 2023
Default Re: What would be the stats for 40mm dragon's breath round

Thanks. I think that covers my question.
shazz is offline   Reply With Quote
Reply

Tags
dragons breath, grenade

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:02 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.