I have a gunslinger player in my game who also invested heavily in craft(alchemy), so he could "invent" the grenades that can be found in the alchemical weapon section of ultimate equipment.
I had him invent them, because guns are so rare that it is nigh impossible to buy one outside of Alkenstar and most people haven't ever heard of black powder as a whole.
Recently, he has made the necessary rolls and built some greades, tested them in combat and of course, the one and only thing happened, that ALLWAYS happens, when you give a P&P player explosives.
He wants to build bigger ones that do more damage.
Since that is technically possible and he invented the standard ones, I don't want to outright forbid this, but I also don't want to make it to easy or to game breaking.
So now my question:
What would be the market prices, craft DCs and stats for better/different grenades that you would allow?