ClydeFrog PB&J is not a company.
Would you go on a car lot & say: G&M?
Would you use B and M and W? Probably not.
Illogical argument is illogical.
G&M?.........GM, because its General Motors, not General & Motors.
B and M and W?..........again its BMW, because the name is Bavarian Motor Works (Bayerische Motoren Werke in German), not Bavarian & Motor & Werken.
Hence the reason to say "H&K" has nothing to do with the factory but because their name is Heckler AND
And I would bet that if I started a firearms company Hart & Kooks and referred to it as "H&K".............they would sue (Heckler & Koch being very litigious) for trademark infringement, copyright violation, trade dress and mopery.
Funny, but ever hear a Smith & Wesson employee refer to their company as "SW"? The only H&K rep I deal with NEVER refers to "HK" except when discussing a model with HK in the name..........he's always careful to use "Heckler & Koch" when he calls.