Heavy fire in pub to go unchecked? (7)

I believe the answer is:

barrage

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'heavy fire' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for barrage that I've seen before include "Continuous fusillade or a torrent of questions" , "Artillery bombardment; barrier across a river" , "Continuous artillery fire" , "a lot of shells" , "Heavy, continuous fire" .)

I've seen this clue in The Sun.

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