This happened to my friend. My friend was picking up the barrel but then another one of my friends opened the barrel at the exact same time which caused my first friend to have the barrel stuck in his hands permanently.

I also got a barrel stuck in my hands. Last night I picked up a barrel in Pushtoshka, nothing seemed to be out of the ordinary until I tried to drop it to drink from a well. I could use the pump, but neither my character or the barrel received any water. I ended up having to switch servers and run to Zeloenogorsk, where some friends were nice enough to lend me the use of some other barrels to store my gear before putting a bullet in my head. The barrel that I was carrying disappeared.

Hello superm and thank you for the report.
This is a known issue and has been scheduled for a fix.
We have removed the barrel from your inventory so your characters hands slot should be usable once again.
Regards,
Geez