Idk stuff about things like an army nerd, but I assume that used to be an ICBM before the photoshop, which the internet tells me are at least 18m long and around 2m in diameter, which is about 55m³, but we should round down bc it's not a perfect cylinder so I'm gonna say 50m³.

I couldn't find the density of loosely packed dried & ground weed, so I found that for tobacco instead here which says 320kg/m³ so that's would mean an 18m long joint with a 2m diameter would contain at least 16,000kg or 35,250lbs of weed