Interesting thread, Captnq
And sorry to hear about contributors / taking over handbooks. I hope that does not feel too much of a downer for you. I have learned a thing or two from your threads. So, please, keep em coming.
back to topic
The weapon itself (Large exotic ranged weapon, Sand Blaster) has barely anything for PCs other than the prize 30 gp (sell it for 15 gp). I guess weight would be something that the PCs would need to know in order to use it. Can they even lift it?
For the Sand Giant Special Attack, Sand Blaster the save DC calculation is in the rules:
http://www.d20srd.org/srd/monsters/intro.htm#specialAttacksAndSpecialQualities. As stated before:
10 + 1/2 the attacker’s racial Hit Dice + the relevant ability modifier (con, in this case)
For PCs I have not found rule that would state how to calculate it. For example for spells it would be 10 + spell level + ability modifier, and for other abilities as well. So 10 appears to be the base always for DCs.
So one can extrapolate for PCs (that are not sand giants) that it could be something like 10 + nothing? + con modifier. Maybe somebody can find a rule that difficulty classes always use 10 as a base. If so then book + page reference would be appreciated.
The Sand Giant's special attack Sand Blaster looks like to be extraordinary as spell-like or supernatural does not really fit to it. So with polymorph and shapechange a PC could use the weapon as extraordinary special attack. I think the DC would then be 10 + 0 (half racial hit dice) + con mod, as the PC would not have the racial hit dice. Even then lifting the thing remains an open question.
Tangent: Would Sand Blaster (extraordinary special attack) provoke an attack of opportunity?
http://www.d20srd.org/srd/combat/actionsInCombat.htm#extraordinaryAbilities would suggest that it would not. Also it would be a standard action to use.
I suppose the user can fill as a full-round action the Sanb Blaster with 5 pounds of sand such as beach sand or desert sand. Can the san be or mixed with something else, veers easily into house rules.
I see some interesting possibilities for DM, when Sand Blaster is filled with something hilarious.
A side note. I seems that the Sand Giant Champion put its ability score improvement to strength. Also the Sand Giant uses a different base ability scores than the Champion when subtracting the racial traits from the ability scores. Not that this tidbit is useful for anything