A person I know has an older K38 that belonged to his grandfather. From his description of it, it sounds to be in excellent condition. I'm concerned about what he's using to shoot in it. He's shooting rat shot to shot pigeons in a barn. Is there any harm or precaution in shooting rat shot in it? I am somewhat concerned about shooting rat shot in it because of leading and no lube. If it was not a somewhat collectable and belonging to his grandfather, I wouldn't think much about it.