Low Tech cannons mortars and shells

[Anthony]

Originally Posted by Rupert

However, the way GURPS does fragments implies that as the warhead gets bigger the energy put into the fragments drops, as a fraction of the total (which is questionable), and for artillery shells it could well be negligible.

That has more to do with the rules for blast damage being broken than with the rules for fragments being broken. Fragment damage being linear in shell diameter is entirely reasonable, the problem is that radius for blast effects should also be near linear in shell diameter, not 3/2 power (what it actually should be in both cases is damage that's linear, and also a wounding multiplier that's linear; a bomb that's 8x more massive produces a given overpressure at 2x the range but also for 2x the duration, and it produces fragments with 2x the penetration but also 2x the wound channel).