[Semiapies]

"A captive-bolt stunner is a quick strike that stuns."

If it's successful, yes. They often aren't; it's not hard to find undercover video of "stunned" animals in clear, loud pain.

Let's take this whole what-if to the extreme:

If I had to be turned into a cow and slaughtered and was given the choice of a random secular slaughterhouse that would use a stunner and a random kosher slaughterhouse, I'd absolutely choose the kosher option. I'd have a better chance of not being injured and mistreated on the way to my death, and I'd have a better chance for a clean, quick, and minimally painful death.