The (magazine-fed) blaster appears to have quite a high capacity, offering eleven-ish shots at full power or over fifty shots at standard power. Also there are extra mags stored in the holster, giving our hero the ability to fire, potentially, hundreds of rounds before running out of ammo.
“Cert. It’s wasteful, though. At full power, I’d empty the magazine
with twelve pulses.”
“What the hell is that thing?” he demanded. “What d’you call it?”
“I’m afraid we call it a ‘blaster,’ ” she said apologetically, and he
closed his eyes. He should have known, he told himself. “As for what
it is, that’s a bit hard to explain—inevitably.” She met his
long-suffering gaze understandingly. “Think of it this way, Dick: it’s
a capacitor-fed energy weapon which projects a pulse of plasma at the
target. On full auto at full power, it delivers approximately
one-point-eight k-tons of energy per second, or just over twenty-one
and a half kilotons for the magazine, since it cycles at a pulse a
second. Of course,” she added thoughtfully, “if you pump the full mag
that fast, you’ll burn out every time.”
“Jesus!” he said, remembering the extra magazines in the back of the
holster. “You’re a walking tactical nuke! Isn’t that a mite
excessive?”
I don't see any indication that the magazines can be user-recharged, noting that an empty mag is treated as lost.
Aston had begrudged the time Ludmilla had been forced to spend telling her story firsthand so many times, but in the event it had been worthwhile. She’d used up the full charge of one blaster magazine demonstrating it to prime ministers, premiers, and generals on three continents, but it had put any doubts to rest.