Green’s Dictionary of Slang

buffer n.5

[? echoic of a dog’s bark]

1. a pistol.

[Scot](con. 17C) W. Scott Redgauntlet (1827) 130: ‘I see you are provided with arms.’ [...] ‘Ay, ay, sir; here be a pair of buffers will bite as well as bark.’.

2. see bufe n.