Greetings! I am new to the prop building world here and I have one of my first projects on the table. I've purchased a very nice 3D printed kit for Malcolm Reynolds' pistol from Firefly/Serenity. The construction looks easy enough however the finished product is going to be very light. There's room and space to potentially add 'something' such as a past or perhaps a resin or something to add some weight to the piece to give it at least a little bit more heft. As I see it, this could be done in the handle and in the barrel. Might anyone have a suggestion as to what I might use to add some weight? Again, I'd like to use a substance that can fill in an open area and dry as opposed to say adding bb's or something that will rattle around. You're thoughts are greatly appreciated. Thanks!