Whenever you hold down fire on the Eruptor, for the people who use the Eruptor at least, you'll see that the follow-up shots after the bolt racking is misaligned, with projectiles flying to the right/up-right-ish of the crosshair. This should hopefully fix it.
Not my mod, reposted from somewhere I've forgotten the source of.
All credits go to KaruRega.
All credits go to KaruRega.