Raider has alot of glaring flaws, but it has standard armor.
That part actually makes little difference for two reasons: one, even commercial armor stands up well to 5-point clusters and smaller hits, which is all the
Raiders can dish out at range; and two, the
Arbiter has "heavy industrial" armor, which is basically just standard plating by another name anyway. The higher chance of inflicting crits on the industrial skeleton underneath
is a factor, but you'll have to score a TAC chance or punch through that armor the old-fashioned way first.
And I'd completely overlooked the AC-armed
Arbiter variant (I blame it not being included with MegaMek yet). That actually changes the dynamic slightly, since if we're using those instead and they can avoid getting caught at brawling distance they suddenly
do have some ammo endurance, plus depending on which
Raider models they encounter a weapon that's either more accurate at range or else packs a more concentrated punch than their opposite number's RAC/2 does at fewer heat woes and no risk of jamming. That fight might just end up being one the
Arbiters have with some careful management an actual shot at
winning.