No, I think your actions were prudent--except for one of them.
You define the place as a "stop n' rob." I don't know if you're using a humorous epithet, or if the place was the magnet for past crimes. If there were crimes in the past, a jug of milk is hardly worth the risk.
As for the Harley, you darn near have to be a doctor, a professor or a hobbyist forum owner
to afford a Harley. Knowing what I do about payments and repairs, my guess is that you ran into a dentist who likes leather.
As for firearm retention, it is your gun, and you are responsible for any and all actions and rounds fired while the firearm is in your care. For example, I can be arrested and sued even if I'm not home. If I leave a pistol out in the open, and a teenage cat burglar blows his head off, I'm still rsponsible.
I'm not sure that the law would care much if the pistol was snatched by a biker or a used car salesman.
Personally, and from experience, the used car salesman is a lot more bloodthirsty.
Edit: wearing a purplue tutu
--I hit the gym everyday and I have lovely legs. If anyone could pull off that look
and still gig an attacker with a knife, it's me.