Hm. I just wrote up a post about how on both Stargates, the villains could probably use gamma ray radiation to kill someone (read: our enterprising heroes) through the iris and/or shield. Which, of course, prompts the question of, "Why the hell haven't they done it already?" To which I have no answer.
And then I started thinking about the Daedalus's shield, and which forms of electromagnetic waves it could let through (yes to radio waves and light waves; no to infrared or gamma waves -- otherwise, what with the number of nukes that they've been setting off, Caldwell would be quite sterile by now, not to mention DEAD). And, of course, I'm pretty sure they block matter, because otherwise any time they ran into a Hive ship, it'd just take a Wraith dart or two to blow the Daedalus to smithereens. But I'm pretty sure that they've had some 302s dock in the middle of a battle, when the shields would presumably be up, which makes no sense. Of course, the type of shield they're talking about doesn't really make sense, either ...
At that point, I remembered that this is a TV show, and therefore they can do whatever they want with their science. Including screw it up royally. So I'm just going to suspend disbelief and pretend that I never had the idea about gamma ray apocafic in the first place.