There's also a point where you have to have some common sense. Yes, the rules let you extend the range on sandcasters, but it's basically meaningless. Sandcasters function by putting a cloud of magic dust in the space between the enemy and they function like missiles that deploy chaff at a designated point. At least, that's how they worked back when they weren't time travelling into the past to block light speed weaponry that you were firing in reaction to.
You can also immediately detonate the canister to make it basically a shotgun to shred nearby personnel, whether in space or atmosphere. Even if you could design a weapon to fire improvised canister at extended range, this isn't a thing that would actually be built. You would build something actually designed to deal with boarding parties, not make your half arsed desperation action into a 3/4 arse desperation action for the very rare times it would come up.
Because for that to actually matter, first you need personnel trying to board by spacewalking while you still have a facing turret weapon manned and functioning. Which is the dictionary definition of seeing a pink unicorn.
You can also immediately detonate the canister to make it basically a shotgun to shred nearby personnel, whether in space or atmosphere. Even if you could design a weapon to fire improvised canister at extended range, this isn't a thing that would actually be built. You would build something actually designed to deal with boarding parties, not make your half arsed desperation action into a 3/4 arse desperation action for the very rare times it would come up.
Because for that to actually matter, first you need personnel trying to board by spacewalking while you still have a facing turret weapon manned and functioning. Which is the dictionary definition of seeing a pink unicorn.