None of my light twelves weigh more than a few ounces over six pounds even with 30" barrels. I shoot RSTs, Polywad Vintagers, AA Featherlights or similar and never have a problem killing birds or having to visit a physical therapist afterward. I have a few sub gauge curiosity guns but the light twelves are, and likely always will be, my go to guns.
I will admit that there are more and more parts of my body that sometimes experience tinged of pain. My doc always starts my consult with......."Now as we age"........I hate it but, of course, he's right. I'm certain though that none of it is caused by my guns, at least yet.
