They are front heavy, ...Thinking about putting some kind of weight inside the unused buffer-tube, any ideas ?
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You can use plumber's putty with lead BB's mixed in to it. That way you have a chance to remove ballast if it doesn't work. For more permanent ballast you can use epoxies (any cheapest stuff) again with BB's or lead shot. You can get really fancy and have removable screw-in steel rods that will go into glass - thats my favourite.




















































