Lock and Load: The Reassembled Machinist Guide

[Pentara]

I think to get that last split shot in before wildfire goes off, the timing looks pretty tight.

Yea without removing the gauss barrel you wouldn't be able to fit it in.

If you watch the video Aiurily posted you can see it gets removed several times throughout the fight then re-applied right after split shot, I'm assuming that it's to not have to wait for a splitshot cast time.