silver bullets vs louper

Murphy, standing at her full five-feet-and-change tall, was shorter than the loup-garou, its eyes on level with hers. She was wearing jeans again, hiking boots, a flannel shirt rolled up past the elbows, a bandana around her throat. She was without makeup or jewelry, her earlobes curiously naked and vulnerable without earrings. Her punky little haircut fell down around her eyes, and as she raised her gun, she thrust out her lower lip and puffed out a breath, flipping her bangs up out of her vision. She started shooting when the loup-garou was about thirty feet away - useless. The thing had laughed off bullets fired into its skull at point-blank range.
I noticed three things at that point.
First, Murphy's gun was not the usual heavy-caliber Colt semiautomatic she carried. It was smaller, sleeker, with a telescopic sight mounted at its rear.
Second, the gun made a sharp little bark, bark, bark, rather than the more customary wham, wham, wham.
Third, when the first bullet hit the loup-garou's chest, blood flew, and the creature faltered and buckled, as though surprised. When the second and third shots slammed into its front leg, the limb slipped and went out from under it. The loup-garou snarled and rolled its momentum to the side, put its head down, and simply smashed its way through the wall and into the room beyond.
Murphy and I were left in the dust-clouded hallway, the escape alarm whooping plaintively in the background. Murphy dropped down next to me. "And I told Aunt Edna I'd never get any use out of those earrings," she muttered. "Christ, Dresden, you're covered in blood. How bad is it?" I felt her slip her hand inside an enormous tear in the blue jumpsuit that I hadn't seen before and run her palm over my chest and shoulders, checking the arteries there. "You're under arrest, by the way. "
"I'm okay, I'm okay," I panted, when I could breathe. "What the hell happened? How did you do that?"
Murphy rose up, lifted the gun to half raised, and stalked toward the hole the loup-garou had left in the wall. We could hear crashing sounds, heavy thumps, and furious snarling somewhere on the other side. "You have the right to remain silent. What do you think happened, moron? I read your report. I make my own loads for competition shooting, so I ran off a few silver bullets last night. But they're only in twenty-two caliber, so I'm going to have to put one through his eye to take him out. If that will do it. "
"Twenty-two?" I complained, still breathless. "Couldn't you have made some thirty-eights, some forty-fours?"
"Bitch and whine," Murphy snarled at me. "You have the right to an attorney. I don't make my loads for work, and I didn't have the materials for it. Be happy with what you have. "

Fool Moon Chapter 18, Page 206-207