It's not an argument about whether or not a character can survive a gun-shot -- not entirely. Being run through with a sword is as liable to put a damper on your day as being shot, in terms of whether or not you're about to shuffle off the mortal coil due to fatal wounds.

The issues with firearms [b]IN MILD POWERS[/b] are threefold:

1) The ability to attack at range at speeds that are, by and large, going to be impossible or nearly impossible to dodge or accommodate. See: a 125 grain .308 Winchester travels at 3,100 ft/s. If someone is 100 feet away, you have .03 seconds react with a meaningful defense, be it a dodge or a block. At mild powers, that's not likely to happen.

2) No particular draw-backs or means of mitigating the weapon's use. This is especially an issue with automatic weapons. If I have a [url=https://www.youtube.com/watch?v=VkOvLkc4kK8]Glock 17c[/url], it doesn't matter if I miss my first shot. I have sixteen others. At least with a bow or crossbow, I have to re-nock and draw. With a firearm, that action is removed entirely until you have to change your magazine. If I have 17 rounds loaded, I have, effectively, 17 attempts to hit you. No cooldown, no preps or charges required.

3) The capacity for [url=https://youtu.be/gVgfohZexjk?t=6m16s]enormous tissue damage[/url]. Sure, you can find outliers who survive getting shot. You can even find soldiers who might continue to fight in some circumstances. But you know what you find a lot more of? People who died. Millions of them. Tens of millions, from WW1 onward. Even if a person can survive, that's not really the question. The question is: what kind of damage am I doing? The answer varies, but usually falls into the area of "a fucking lot." The next question is "How hard is it for me to do this damage?" and the answer is "Not very."

So what you have is: a weapon capable of striking from a considerable distance, capable of doing enormous amounts of trauma/damage, that has no draw-backs to its use. It's essentially stronger than any supernatural power a character might have at mild powers, but has zero limiting factors other than how many bullets and how talented the character is at shooting. And let's be real: the former is a minor issue, and the latter is probably non-existent when every character is essentially proficient at their chosen form of combat. The reason people disallow guns in mild powers isn't solely because of the fatality of the weapon. A sword is fatal, but I can't hit you with a sword seventeen times from 100 feet away at 3,100 ft/s in mild powers.

The question isn't "Can someone survive it?" The question is"Can someone reasonably defend against it?"

Again, this is purely for [b]MILD POWERS[/b]. There's absolutely zero reason to disbar guns from higher tiers of power. Guns are actually one of the reasons I will play at higher tiers, because otherwise they see so little use. My Kindred vampire uses guns, and used to get shot all the time. My Shadowrun character, as previously described, will gladly run face-first into gunfire. But these characters are meant to be played at a level where firearms aren't game-changers.