Fair enough. To be honest, I find myself doubting Morishima is an expert on firearms.
I'm reminded of when Murphy and Sapir were writing the Destroyer series of novels, they included a firearm in one book and people called them on the mistakes they made about it. They agonized over it for a while, having made such obvious errors, until they had (more or less) this exchange.
"Do you care about guns?"
"Well, no."
"Do you care about people who are that fussy about guns?"
"No."
So from then on, whenever they included any sort of firearm in their books, they deliberately got all the details wrong, and came up with ridiculous weapons that nobody would really want to be real.