Low Tech cannons mortars and shells

[Rupert]

In reality, if you're inside a certain distance (dependant on the shell) and inside the fragmentation pattern you will get hit, and if you're outside that the chance drops off fairly rapidly. A well-designed modern (anti-personnel) shell also has fragments that lose energy very quickly past that saturation point, so damage drops off as well as hit chance.

However, I don't think that'd result is a whole lot of fun, given the extremely binary results this tends to bring, so using the RAW or modifications of them is probably a better way to go.

For low TL shells I'd consider changing the base hit chance to 7+TL from the standard 15-. At TL4 possibly increase the per-fragment damage by 50% or 100% to reflect their large size (at TL3 the shells tended to break too quickly, so the explosion didn't impart much energy to the fragments). Possibly also increase the 'Rcl' from 3 to 4 (fewer fragments also means less chance of multiple hits).

For modern TL8+ shells that are designed for anti-personnel work, reducing damage to buy more hits is reasonable - every halving of energy means twice as many fragments, and thus +1 to Hit but doing 70% of the base damage. Shells with very dense fragment patterns should also have reduced maximum radius (they're so small they lose energy very fast), but might have Rcl 2.

I'd definitely adjust the base hit number based on shell/bomb size (as I mentioned earlier in the thread).

If you want to get picky, a 1/2D radius would be reasonable, but I'm not sure what it would be (probably the fragment damage dice times some constant, and that constant would be different for pre-formed 'fragments' like balls).