thumper
n.— «To make things even more out of balance, the Ruger has a .449″ bore. It is a real shooter tho when .455″ bullets are used and I use it for my “thumper” loads.» —“Re: Charter Arms Bulldog 44spl.” by Norman F. Johnson (njohnson@nosc.mil) Usenet: rec.guns Apr. 7, 1994. (source: Double-Tongued Dictionary)