UK maker Nick Thatcher’s pistol-sized coilgun is a mere 15cm (5.9″) long and uses 5 caps taken from disposable cameras. I think the brass bars are just to make it look like a raygun.
On my last coilgun the charging unit was built in, this resulted in a rather hefty box slung underneath the main gun, on this mini coilgun however in order to save space and improve looks I decided that this wasn’t necessary. instead when the gun needs to be charged the gun can be plugged into the holster (under construction) which will charge it up and then be removed when ready to fire. Alternately a charging cable can be continuously attached to the gun, perhaps with the help of a backpack this may even facilitate rapid fire.