I agree with you in spirit, but you don't know what kind of arms tech they have in Marvel U. Especially in the Hydra organization.
I thought Mcniven was awesome as fuck.
Not to hijack (but I'm going to do it slightly), but hate it when creators use that kind of excuse. I can buy it with a totally fictional world, but something like Cap is set in a world not unlike our own. Brubaker makes his share of firearms mistakes in Criminal too. Dude likes to write about guns....so he should learn about guns.
I only bring it up because it's these little moments that pop the bubble and yank us out of the story. I'm sure it's hard for the writers, because all of us readers have these little pockets of knowledge. But, while they don't have to get everything spot-on correct, they should strive to not get anything wrong.