Run out

[LordOfTheRings]

Please, help me translating "run out" in the following sentence.

"Mounted amidships was a turret with ports and, as we looked, the
turret began to revolve until her forward gun bore directly on us and, run out, it
resembled a cheese box on a raft"

Thank you.

[Bennevis]

= and being run out - in that position (after it came out)

[BobK]

= and being run out - in that position (after it came out)

To clarify, it was on runners, and advanced ('run out)' before firing.

b