Game rule or a bug?
 

I'm very, VERY new to Mutants and Masterminds.

I am attempting to create a very simple character. The character has Dex 3 and Ranged Combat 5.
I gave him a Heavy Pistol and a Shotgun, and made sure his Ranged Combat skill covers both (selected both in the Affects Attacks window).

His attack bonus with the pistol is +8. His attack bonus with the shotgun, however, is +7.

Is there a Mutants and Masterminds rule to account for this, or is it a bug? The shotgun has Accurate 1, but if that was accounted for in Hero Lab, that would make the bonus +9, not +7.

I just went in and tried to produce the result you're getting, and can't do it; both are coming up at +8 for me.

What is the PL of your character? And is he coming up with warnings? IIRC, the shotgun has a higher damage rank, which could mean that you're running up against caps.

Duggan, that was exactly it. The character was PL 6, and the +5 damage on the shotgun put him one point over the PL cap. The odd thing is that it reduced his to-hit bonus instead of giving me a warning.

Thanks!!

If you have more than one warning (common in 3E if you haven't set Complications), you might not see it until you click through. But glad that we could help. :)

And of course, the Accurate should be accounted for; it certainly effects PL caps.