I believe you have a CVA Blazer. The barrel and possibly other parts were made in Spain. The nipple is located in the center of the breech plug-a forerunner to today's modern inline muzzleloaders. CVA was offering a recall on these guns-if you've ever fired it you'll know why. If you haven't fired it I recommend you don't-the nipple could possibly blast free and injure or kill you!
30 caliber with 30 grains of powder
Impossible to value a weapon with just the caliber and serial number to any degree of accuracy.
50-150
such black powder revolvers are anywhere from $150 - $250, depending on condition
No But the Caliber is the same but theres more powder in the 223
1gran per caliber
50-450 usd
No published sn data.
There are generally 2 types of BP firearm, 1 muzzleloaders, loaded with powder cloth patch and lead ball or mini ball (also powder and a sabot and bullet in the more modern guns. 2 Black powder cartridge guns, that fire a more conventional looking self contained cartridge loaded with black powder and a bullet. such as the 45-70 or the 30-30 ( first number is the caliber second number is the grains of black powder in the cartridge. 45 caliber with 70 grains of powder) I am greatly generalizing
75-100 grains of powder.
Depends on the caliber. A .45 caliber pistol uses about 40 grains of black powder. Contact the maker's website and download the owner's manual for YOUR gun.
There are a lot of variables involved with the number of grains of powder in any given caliber round. Most importantly are the type of powder and the weight of the bullet. After that is the loader's preference as to the velocity of the round. For example, I load a 155 grain .40 caliber bullet using Ramshot Zip powder for a "light" velocity of about 1050 feet per second using 5.3 - 5.4 grains of powder.