E. R. Armentino shows in my references only as a maker of shotguns. The .300 Holland & Holland is, of course, a rifle, and I find no listings of rifles in their products.
That is a VERY long list. Beretta lays claim to being the oldest gun maker still in operation. Some of the others have included Mauser, Walther, Holland & Holland, and Westley Richards. Depending on which country, there are HUNDREDS that can be on the list.
The gun maker never sees a customer. Guns are sold to individuals not by the maker, but by a gun dealer. No, it is not the dealer's responsibility to ask a person what they are going to do with a gun.
Maker or manufacturer.
Mainly from the markings on the gun by the maker.
By maker information.
Remington is the oldest maker still in operation.
He was not noted for it.
Colt was one maker who made the GATLING gun.
Contact the maker, gun show, gun shop, library
Amati andrea
Write to the Manufacture or go online to the gun maker and request a manual.