Re: In Gurps, how powerful do you need to fight a tank?
 

.50BMG AP is officially 13d+1(2), so needs about DR 90. That's probably overestimating its actual performance, but it's the 'official' value.

Re: In Gurps, how powerful do you need to fight a tank?
 

The M2 with old school API-T does 5dx2 (2) pi inc, High-Tech p. 133. So DR 70. I was off by 10. At any rate you aren't popping tanks with it. You certainly aren't popping anything that was designed or upgraded (like current M1A2s) for MOUT.

Sabot is 6dx3 (2) pi, so DR 84, which as noted, even the T-72 is protected against.

There's a reason why attack helicopters mount bigger guns.

Re: In Gurps, how powerful do you need to fight a tank?
 

Is the Raufoss statted out as SAP - AD (1) - or APHEX - AD (2) - in GURPS? If the latter, that might let it kill the crew (with AP, you've got to get a lucky shot where Hitting the Wrong Target results in a crew member getting got, but an internal explosion is going to be a lot more effective; technically against DR 60 that 13d+1(2) pi is going to result in "only" around 5d-1(2) pi getting through, which I think Level III armor might be able to at least drop below the Major Wound threshold, and I'm fairly confident Level IV armor would stop outright, but I don't know how common it is for tank crews to be armored up to that level; I'd expect them not to be very armored due to the confines of the tank, but I could be mistaken).

Re: In Gurps, how powerful do you need to fight a tank?
 

The RAW's procedure for vehicle hits is on B555, and is not 'hit the wrong target' (aside from anything else, it's in addition to the damage to the vehicle). Assuming the tank is SM+4 and has 3-5 crew (which describes all the tanks in HT aside from the FT17), a penetrating hit of 5+ damage will hit a crew member on 9-, with damage being cutting, at 1d per full five points of penetrating damage.

As far as I know, Raufoss ammo has not been explicitly named and statted up, but HT says "APHEX-T (Dmg 7dx2(2) pi with a 1d-2 [1d-2] cr ex follow- up) has also seen use since the 1980s", which should cover it, given that both explosions and tracer rounds are incendiary by default.

Re: In Gurps, how powerful do you need to fight a tank?
 

Nominal penetration is listed at 11mm at 45 degrees at 1,000 meters. 11mm is DR 31, increased to about DR 45 for a 45 degree angle, though presumably short range penetration is higher.

Re: In Gurps, how powerful do you need to fight a tank?
 

That's right around 13d penetration, and I believe 1,000 meters is within the 1/2D range for a typical .50 Browning rifle, implying SAP (no AD), and thus indicating it would likely splash on the top armor of a tank... but Rupert's quote from HT matches up with it representing the Raufoss Mk211/Mk300 (which apparently were first made in 1981). 14d(2) would call for DR 98 to stop it, corresponding to a flat-on hit to 1.4" (35.5mm) of RHA.

Re: In Gurps, how powerful do you need to fight a tank?
 

There seems to be a general issue with penetration for most AP rounds, probably because the armor divisor shouldn't be (2).