I think (I hope) everyone is in agreement that guns do not belong on airplanes, except as empty and declared checked baggage. Screening for firearms should continue to be a major priority of any passenger screening regimen.

The question is: does the TSA making yet another declaration of 'success' provide any supporting evidence that its screening methods and procedures have 1) found more firearms than pre-TSA screeners, and 2) the firearms confiscations by the TSA resulted in an intended threat to passenger safety being averted

I would say 'no' to the above. Let the private screeners with some improved training and oversight continue to use pre-9/11 passenger screening methods to find the guns - and - let a significant fine be levied against any dingbat passenger who decides to try and carry their gun onboard (which would preclude a good number of entertainment celebrities from flying)

If the time comes when statistics are collected from private screeners to compare to the TSA's results, I am sure the number of confiscated and missed weapons will be about the same. The number of angry and frustrated travelers will be far less without the TSA, though.

Fly4Food is correct - a firearm discharge is unlikely to result in an airframe failure unless the bullet ends up piercing the wing fuel tanks in a bad way - highly unlikely - however, we still don't want guns on board.