From a purely business sense it does not pay them to have someone spend too much time running down a difficult problem. If you think about the value of one particular gun versus the labor cost you can see why it is not only easier but more cost effective to send a new gun.
I decided to wait until they get more .22's in. I think when we get closer to mid October I'm going to drop them a line reminding how long they've kept me waiting and suggesting they can make up for it by making sure I get one with a really nice stock (they already said they'd test it before sending it).