Something to test for is ability to insert a full mag into the base with lockup while the slide is forward. I've found problems at home or the range where a full mag could not be inserted and secured with the slide forward. This is USUALLY discovered while trying to load +1.
It's better to find this out before you're slowed down in a defensive situation.
USAF Retired '88, NRA Life Member. Wife USAF Retired '96
Avatar: Wynn re-enlists his wife Desiree, circa 1988 Loring AFB, ME. 42nd BMW, Heavy (SAC) B-52G's
Frédéric Bastiat’s essay, The Law: http://mises.org/books/thelaw.pdf
Thomas Jefferson said
“A government big enough to give you everything you want, is strong enough to take everything you have.”
and
"Peace is that brief glorious moment in history when everybody stands around reloading".