TL 5-8 firearms in Ultra-Tech calibers

[Michael Thayne]

Here's a pass at some stats for generic, ahistorical black-powder flintlocks using the -1 damage per die and 90% of range rules found in Pyramid #3/88:

Guns (Pistol)
TL Weapon                 Dmg.      Acc Range.    Weight Rof Shots ST Bulk Rcl Cost
5  Flintlock Pistol, 10mm 2d+1 pi+. 2   160/1,800 2/?    1   1(20) 10 -2   3   $?

Guns (Rifle)
TL Weapon                Dmg.      Acc Range.      Weight Rof Shots ST  Bulk Rcl Cost
5  Flintlock Rifle, 10mm 7d-1 pi+. 5   1,200/5,200 9/?    1   1(60) 10† -5   3   $?

Guns (Shotgun)
TL Weapon                  Dmg.     Acc Range. Weight Rof Shots ST  Bulk Rcl Cost
5  Flintlock Rifle, 18.5mm 1d pi++. 3   90/450 6/?    1   1(40) 10† -5   4   $?

Above results seem reasonable for the shotgun—range might even be too low. But rifle and pistol stats seem too god. Something something improvements in bullet design which the Pyramid article assumed could be preserved? Alternatively halving both damage and range:

Guns (Pistol)
TL Weapon                 Dmg.      Acc Range.    Weight Rof Shots ST Bulk Rcl Cost
5  Flintlock Pistol, 10mm 1d+2 pi+. 2   90/1,000 2/?    1   1(20) 10 -2   3   $?

Guns (Rifle)
TL Weapon                Dmg.      Acc Range.     Weight Rof Shots ST  Bulk Rcl Cost
5  Flintlock Rifle, 10mm 4d+2 pi+. 5   6500/2,900 9/?    1   1(60) 10† -5   3   $?

That's more in line with High-Tech. Thoughts?

I also want to do some Ultra-Tech style write-ups for TL5-8 projectile options, but I'll worry about that later.

[Kale]

Originally Posted by Fred Brackin

Nope, never heard of them (and especially not in a Gurps book). No dates were given except for "late 80s" for the later "monad" bullets. Most of these firearms go back to Ultra-tech Two published in 1997. The original 10mm auto pistol was in Space 1e and the Assault Carbine was in UT1. Cyberpunk figures in there too.

Sorry, wasn't referring to 3rd ed, but you are totally right. I didn't mean THV specifically (with their spoon tip wackyness) as much as the whole movement to lighter high velocity bullets. The 5.7 FN and 4.6 H&K rounds have a high speed and unusual light tip construction to encourage tumbling to make up for their small bore. I was also referring in that case specifically towards intermediate PDW cartridges. This occurred somewhat after the 3rd ed UT and I feel it influenced 4th ed UT.

[Kale]

Originally Posted by Michael Thayne

But rifle and pistol stats seem too good.

Yeah hitting 7d with a 10mm black powder projectile seems way too high. I suspect you could do it with modern metallurgy, but if you restrict yourself to the materials historically available you'd need a massive weapon to handle the chamber pressures.

[Varyon]

Originally Posted by Kale

Yeah hitting 7d with a 10mm black powder projectile seems way too high. I suspect you could do it with modern metallurgy, but if you restrict yourself to the materials historically available you'd need a massive weapon to handle the chamber pressures.

It's doable with Vehicles, but only just. At TL 5, a 10mm, maximum power rifle with a long (~60-79 calibers, or 600-790 mm) barrel would do 7d-1 (technically 6.75d). It would weigh in at 13.5 lb, have Range 140/1100 or so, and have 3e Acc of 8 (roughly 4e Acc of 4). My simplified/modified version of the Vehicles system would result in a 7.5 lb, Range 40/400*, Acc 5 rifle (with a 600 mm barrel) in 4e; I'd put it at Bulk -6 (Bulk -5 by barrel length, a further -1 with the stock). That's a muzzleloader; in either case, a breechloader is about 1.5x the weight, a revolver around twice the weight.

*My system is more geared toward TL 4 or so, so I set Range as being caliber (in inches) x100/x1000, which matched up rather well with the weapons from Low Tech. TL5 probably got better range out of its bullets.

[Fred Brackin]

Originally Posted by Kale

S The 5.7 FN and 4.6 H&K rounds have a high speed and unusual light tip construction to encourage tumbling to make up for their small bore. T.

This isn't accurate. The original 5.7mm round (the SS190) has a solid steel (density 8) tip in the shape of a cone and then a cylindrical body of aluminum (density 4) so it's a _heavy_ tipped design and not a light one. It's pretty much the opposite of how you'd design a bullet you wanted to tumble.

The HK 4.6mm is just one piece of solid steel. It's more likely to tumble than the SS190 but isn't really designed for it.

Because of their armor-piercing construction neether will fracture the way 5.56mm rounds are now known to do and much of the 5.56mm bullet's wounding power comes from this fragmentation and not just simple tumbling.

I can't find any real source for the tumbling wounding power of either the 5.7mm or the 4.6mm other than wishful thinking. The one time I've seen ballistic gelatin pictures for them there was just a simple non-tumbling wound channel that wasn't deep enough to meet FBI standards.

Their speeds aren't high by rifle standards either.

[Rupert]

Originally Posted by Kale

Sorry, wasn't referring to 3rd ed, but you are totally right. I didn't mean THV specifically (with their spoon tip wackyness) as much as the whole movement to lighter high velocity bullets. The 5.7 FN and 4.6 H&K rounds have a high speed and unusual light tip construction to encourage tumbling to make up for their small bore. I was also referring in that case specifically towards intermediate PDW cartridges. This occurred somewhat after the 3rd ed UT and I feel it influenced 4th ed UT.

That sort of tip construction is not particularly unusual. The Soviet 5.45x39mm used it, and the old .303 MkVII used something similar, with a fibre insert in the bullet's tip to push the centre of gravity rearwards and make it yaw quickly (and as the base of those bullets was exposed lead, when they yawed the base would flatten, creating a wider wound channel).

[Rupert]

Originally Posted by Kale

Yeah hitting 7d with a 10mm black powder projectile seems way too high. I suspect you could do it with modern metallurgy, but if you restrict yourself to the materials historically available you'd need a massive weapon to handle the chamber pressures.

The .500 Express would probably do 7d-1 pi+ or thereabouts, though it is a 13mm bullet rather than a 10mm.

[Rupert]

Originally Posted by Fred Brackin

The HK 4.6mm is just one piece of solid steel. It's more likely to tumble than the SS190 but isn't really designed for it.

Because of their armor-piercing construction neether will fracture the way 5.56mm rounds are now known to do and much of the 5.56mm bullet's wounding power comes from this fragmentation and not just simple tumbling.

I can't find any real source for the tumbling wounding power of either the 5.7mm or the 4.6mm other than wishful thinking. The one time I've seen ballistic gelatin pictures for them there was just a simple non-tumbling wound channel that wasn't deep enough to meet FBI standards.

Their speeds aren't high by rifle standards either.

That's why the P90 and MP7 are in the submachinegun section of HT. It's also why the P90's standard SS190 bullet is rated as being AP. Neither of these PDWs have performance that's a whole lot better than a PPSh-41, and a PPS-43 (being lighter and having a better magazine) would be just about as good as a P90, and a whole lot cheaper to make. Or, if a WWII SMG is too old-fashioned, an AKS-74U which fires 5.45x39mm rounds with a similar muzzle velocity to the P90's ammo but with bullets double the weight.

[MrFix]

The answer is quite obvious and on the nose.


1) UT went for generic names, including weapons and calibers for ease of play and interchangability.

2) ALL UT Firearms fire CASELESS ammunition and/or perhaps even telescopic. Which is reasonable for a caseless telescopic 5.56x45mm to simply round down to 5mm etc.

3) ALL UT Firearms roughly follow Basic Set guideline for roles of Assault Rifle etc, which is also what HT follows. So relatively similar firearms will behave similarly in terms of damage. For example, TL9 5mm 5d is obviously TL8 5.56 5d

4) Tactical Shooting has caliber conversion rules. You can use them to convert TL8 cased ammunition to TL9 Caseless/Telescopic.

Damage/range/etc probably wont change completely, but the cartridges might be lighter, cheaper or more common. 7mmCL AK74 is gonna have easier time in TL9 society than 7.62x39mm

*Note. CL means Caseless in UT Caliber names. CLP means Caseless Pistol. This is to differentiate between 9mm rifle and 9mm pistol.

[Kale]

Originally Posted by Fred Brackin

This isn't accurate. The original 5.7mm round (the SS190) has a solid steel (density 8) tip in the shape of a cone and then a cylindrical body of aluminum (density 4) so it's a _heavy_ tipped design and not a light one. It's pretty much the opposite of how you'd design a bullet you wanted to tumble.

A quick sampling of ballistics tests note that tumbling was significant in ballistics gel in a number of observed cases. This was for the SS190 bullet, and it looks like there were a few iterations. They also claim the center of mass is near the base of the projectile.