"An attacker with a "long arm" is going to out - shoot anyone with a handgun, on the grounds of both accuracy and magazine capacity.
Even the idea of "concealed carry" is absurd. What sort of weapon is envisaged? A James Bond style Walther PPK? Little better than a popgun in the circumstances. A 38 Special? Maybe, just. A 357 Mag? A bit better, but a capacity of 6 rounds? Pointless. "
I get the feeling that you don't understand how this really works.
You don't have to have extreme accuracy at long range, particularly inside a building. If you are defending a classroom full of children and have moderate competence, a pistol will do very likely, thank you. There should be no problem positioning yourself within perhaps 12 meters of the door, at which range you should be able to put an entire magazine in a 20 cm circle.
Well chosen modern handgun ammunition in appropriate calibres (.357, 9mm, .40 S&W) has a 'one shot stop' percentage equal to or greater than 95%. An attacker coming through a doorway has a pre-determined location, and a properly sited defender will be invisible from outside the room, waiting.
If putting the attacker down 99% of the time takes more than three rounds, you are not doing it right.
Properly chosen clothing and holsters provide good concealment. There are a ton of references if you need advice on how to do it. Different body types will work with different modes of carriage and different weapons... some would find an SP101 or an LC9 ideal, while others could carry a full sized Sig 226 (my preferred choice for the above situation).
Biting the hand that feeds IT
