According to Matt Brackeh, it’s a federal caliber. I dunno if he made that up, but it sounded good in his book! If, in fact, he DID have a federal-caliber Glock, there’s a lot more ‘splainin’ to do.
I’d be curious to know if Glock 20s are only available to law enforcement. If that’s the case, then there really are some serious questions to be answered.