Hey, ALL the conductor is under the terminal at least it was not wrung off (something I've never done
It appears as the type of terminal that will take a conductor on either side, or both as in the case of Square D.
That said, you can splice if there's room, or buy a mac adaptor that reduces the size of the conductor entering the terminal, I think these are made by both Burndy and Ilsco. We used to use 'em for circuits like parking lot lights where you'd have 1/0 for a 20 amp circuit.
Either way, the picture you show doesn't make me 'pucker' it looks like a pretty good installation.
Let the flames begin