The blaster does energy damage, and TTBOMK there is no resistance against that, so if it hits, it should do full damage. But an individual shot from a blaster does very little damage, and they are very poor weapons to use in turn-based mode. Their advantage is that their recovery time is exceptionally short; they fire very quickly, and they do horrendous damage in real-time combat.
As to whether the autotargeting routine that comes into play when you hold down the A key has a built-in "miss" percentage, I have no idea.
This isn't a complete answer, but I hope it helps.