Jawa Blaster - the search for a barrel

Been a delay in this build as I've been trying to find a suitable shape for the barrel.
As I said before, the problem with making one of these is that no-one knows what this strange fluted shape used on the original was:



I've seen folk in the States make terrific versions using very tall plastic tumblers:





But couldn't find anything like that over here. So I've spent the last few weeks scouring department stores, DIY places, plumbing suppliers, toy shops etc looking for a suitable donor.
But then I hit on the idea of maybe a plastic vase might do. Having a trawl on the 'Bay, this lovely blue affair looked to be about right, so I bought one:



Its not 100% accurate, missing that lip at the end, and was a tad too long, but figured, with it cut down to size, it'd pass. So that's what I did. Trouble there was, the diameter of it at the blunt end didn't match with anything i'd already built. So that was all scrapped, apart from the lid of the green tumbler i'd bought, which the blue vase sat just right into.
A quick pop to the 99p store this morning got me this tub of conditioner, which I emptied out, then bolted the green lid to one end, then hot-glued the blue vase to that: