Hello Denis!
thank you for your message :) If I understand correclty, the "Match Selected" button should do what you are looking for. Select the barrel, then click "match selected", and you can start placing it right away. Also there is a shortcut on Spacebar, to select the last object you have been placing, which might be useful.
I hope this is what you are looking for, if it is not, please specify what exactly you would like to do. As to "do it on runtime", I am not sure what you are referring to.
Best regards