Probably not. There is no standardization between makers. Come to think of it, why do different cars use different spark plugs? Same thing.
7627
50-300 depending on specifics
15-50 USD
I don't see dbl in Remington, if you mean the dbl in general when when referring to a Remington firearm that's double as in double barrel shotgun, derringer, etc.
10-100 usd
Remington did not make a 44 cal double barrel pistol. The did however make a 41 cal (rimfire) the double derringer. (model 95) There's 3 type's, 5 models, and at least 15 variations some of which are quite valuable.
A typical starting load for the ball and cap Leinad pistol would be about 15 grains of fffG powder.
$50-$100, depending on condition. FIE was an importer of firearms, mainly from germany- the company has been out of business for some time.
Do you mean you have an extra barrel, or are you calling the tube magazine below the barrel another barrel?
Never heard of it. Need a detalied description of all markings, finish, barrel length, condition. Leinad made several different models of .410/45LC derringers. A five shot pepperbox, single shot pistols, double barrel pistols, and a Model PD which was a two shot revolving pistol.
40-100 USD
They should not be.