Old lawman to carry personal protection (7)
I believe the answer is:
earplug
'personal protection' is the definition.
'old lawman to carry' is the wordplay.
'old lawman' becomes 'earp' (Old West lawman Wyatt Earp).
'to carry' becomes 'lug' (lugging is a kind of carrying).
'earp'+'lug'='EARPLUG'
(Other definitions for earplug that I've seen before include "affording protection for organ" , "It blocks out sound" , "protection for delicate drum" , "Lug blocker" , "Protection against noise" .)