Gauss Weapons table at GURPS Ultra-Tech seems a bit strange.

[Pectus Solentis]

(Sorry if my English is poor. I'm Korean.)

p.UT141
Gauss Rifle, 4mm (TL10): This may be a standard military rifle at TL10. It is an automatic weapon that accelerates a 4mm bullet to almost 5,000 feet per second.

Here says that Gauss Rifle's bullet velocity is 5000ft/s.
And 5000ft/s is translated to 1500m/s.

But, as Ranged Combat Rule says, Non-homing Projectiles moves at its Maximum Range per 1 second. (A target is hit by that projectiles AT THAT TURN when it stands in that Projectile's Maximum Range.)

And, as written at p.UT142, Gauss Rifle that is introduced at p.UT141 has 1200m Effective Range and 4800m Maximum Range.

When I think the Ranged Combat Rule is right, It seems that the Gauss Rifle's bullet veloclty should be app. 16000ft/s (because 4800m is approximated to 16000ft) by its table written on p.UT142, but UT141's explanation says Gauss Rifle has 5000ft/s.

It seems strange...

[Ulzgoroth]

Depending on the edition you have the table may have problems. But in this case, the problem is your understanding.

Originally Posted by Pectus Solentis

But, as Ranged Combat Rule says, Non-homing Projectiles moves at its Maximum Range per 1 second. (A target is hit by that projectiles AT THAT TURN when it stands in that Projectile's Maximum Range.)

No, it doesn't say anywhere that projectiles cover their maximum range in one second. Very very few projectiles do.

For gameplay purposes, ranged attacks are treated as reaching their target immediately. But that says nothing at all about their actual muzzle velocity.

[Pectus Solentis]

Ah-ha... Then treating AS IF the target is hit immediately is not true game mechanism, but just an abstraction?

[Ulzgoroth]

Originally Posted by Pectus Solentis

Ah-ha... Then treating AS IF the target is hit immediately is not true game mechanism, but just an abstraction?

Well, it's truly the game mechanic. But it's not remotely how the weapons actually work.

[Anthony]

Originally Posted by Pectus Solentis

Ah-ha... Then treating AS IF the target is hit immediately is not true game mechanism, but just an abstraction?

It's more a case of 'other assumptions are a giant PITA to handle in a game'.

[Pectus Solentis]

What PITA means?

[Boomerang]

PITA = Pain In The A$$

[AlexanderHowl]

I think a good rules of thumb though is that projectiles reach their 1/2D range in a second. For example, a Gauss HMG has 1/2D range of 2,700 m, meaning that the projectile is traveling around 2.7 km/s. After 1/2D range, the projectile is probably traveling half as fast, since it deals half as much damage. In the case of the Gauss HMG, the projectile would take six seconds to travel the remaining 8,100 m of maximum range.

Of course, the advantage with a Gauss HMG is that there is not muzzle flash and the projectile travels faster than sound, so the target will never know what hit them. Since a Gauss HMG fires 20 rounds per second, the operator could saturate an area from 9,000 m away and leave before any possible return fire could reach them. It takes seven seconds for the rounds to reach the target and, assuming equivalent weapons, seven seconds for return fire to reach them, so they could spend 10 seconds firing and then retreat for 4 seconds before any return fire comes at them.

[Ulzgoroth]

Originally Posted by AlexanderHowl

I think a good rules of thumb though is that projectiles reach their 1/2D range in a second.

Why? You advance nothing to support this, and it makes little physical sense. A heavier slower projectile may often have a longer 1/2D range than a faster lighter one.

[Pectus Solentis]

Originally Posted by AlexanderHowl

I think a good rules of thumb though is that projectiles reach their 1/2D range in a second. For example, a Gauss HMG has 1/2D range of 2,700 m, meaning that the projectile is traveling around 2.7 km/s. After 1/2D range, the projectile is probably traveling half as fast, since it deals half as much damage. In the case of the Gauss HMG, the projectile would take six seconds to travel the remaining 8,100 m of maximum range.

I think that is plausible, because Homing projectile goes as long as 1/2D range at a second.