Ed, I would not consider tumbling anything loaded but you say surplus ammo is ammo that failed some test by the military. I can't agree, millions of rounds of surplus ammo is being sold as the country has now decided thru joining things like NATO to change calibres of their military weapons. Perfect example is the Czech7.62 X 39 that is on the market now. The Czech's now have gone to NATO calibres and have no need for "39" ammo. Of course there will always be some crap on the market but that doesn't make ALL surplus ammo crap. The tins of Czech "39" are sealed and even "pop" when opened proving the contents if stored properly will last for many years to come. Look at all the surplus .303 you could buy years ago, it became surplus as we went to .308 not because it was "bad", I shot some not too long ago and it worked fine.