You can buy pretty model barrels made of plastic, resin, wood or other materials, or you can buy rubber molds for casting to make your own.
Usually they are too expensive to let you use lots of them.
I found this plastic hose in a hardware store. It’s used to guide electrical cables inside walls, but looked like it would be more useful on the table.
I went in and bought a meter of 3/4” tubing (about US $1.00), and I was ready to try my idea.
Comparing the hose with a 28mm miniature, I decided 7 “coils” were about the right size to use, so I cut several pieces to that length (a meter of this tubing is enough to make literally dozens of these barrels).
With the modelling knife I carefully removed all excess plastic left when cutting the barrel, so that top and bottom ended as flat as possible.
Do this trying to make it as precisely as you can, but don’t worry too much if you do make some mistakes. The ends will be covered after all.
Then, with simple cardboard, I made circles just large enough to cover the upper part of the tubing. I used a special circle template but you can use a suitable coin or something like that.
The smaller circles were made using a hole puncher and glued with white glue on the bigger cardboard circle.
You can use white glue to attach the big cardboard circle to the hose, but I used liquid silicon.
I also glued a little rectangle to a side for a warning signal or something like that.
Now you only have to spray them black and drybrush a metallic colour and you’re done!
The finished barrels in the picture don’t have a double small circle on the lid, or the warning signal at a side, but these were my prototypes: The next batch was made with a little more care.
Of course these are “futuristic barrels” you don’t need to paint them as metal at all. They can be any “space material” you can imagine.
As this tubing is sold in various sizes, you can use this method for other scales too, or make different sized barrels.
The hose is stored in coils in stores, so your barrels may be slightly curved.
I found that by submerging the pieces (before attaching the cardboard parts) in hot water, they will straighten up and be almost perfect.