Most likely a cheap nickle plated thing. But not necessarily, there are good guns that can be had nickle plated... but what was it Patton said about Pearl Handled Pistols? Something about a pimp in a New Orleans whorehouse?
she just happens to have her own gun handy enough to shoot him five times before he knows what happened
You don't "just happen" to have a firearm, you plan to have one. She did, although apparently it wasn't in all that "handy" a location. She just surprised him when she came up with it rather than the baby he thought was in the back seat. :)
What point in having a gun if it's not at hand, and loaded, when you need it?
He probably knew what happened after the first time... ;-)
action beats reaction