I've got the thing on my Multi-tool, and it paired "green" with the mining stuff instead of "red" with the boltcaster stuff.
I feel like I'm killing Sentinels faster with the mining beam now, but that might be anecdotal from all the other upgrades I did in that session.
Does anyone have any legit observations, instead of anecdotes or "I think the flavor text means X"?
Best Answer
The rail adapter seems to be a general purpose power boost for the mining beam (which is why it counts as a green mining upgrade instead of a red boltcaster upgrade). It makes you mine significantly faster, and also destroys sentinels quicker as well.
However, this extra "oomph" comes with a price. While the rail adapter is used, the mining beam will overheat much faster than normal, meaning you either need to add several cooldown upgrades or you have to space out its use into pulses (to abuse the heat reset bug). Additionally, it only fires in a straight line, meaning that you have to aim more precisely during combat.