Muzzleloading basics- #2 The Rifle cont.
There are several types of triggers, including the single, single-set, double-set, single phase & the double-set, double phase triggers. Set triggers were designed for target shooting.The purpose of the set trigger is to decrease the length of trigger movement, referred to as "travel", and to decrease the amount of pressure neccessary to pull the trigger. Set triggers are often referred to as "hair-triggers".
A single set trigger, is one trigger, which can be set by pushing the trigger forward, then gently squeezed to fire. This type of trigger does not have to be "set" to fire.
A double-set trigger has two triggers, the rear trigger is used to "set" the trigger, while the front trigger is used to fire the weapon.Single phase triggers have a single function, whereas double phase triggers do not need to be "set" to fire.
There are essentially two types of barrels, "smooth" and "rifled". "Rifling" is a series of spirals called lands & grooves cut into the bore. These impart a spin to the projectile, stablizing it for greater accuracy. "Smoothbores" do not have rifling and therefore present  an additional challenge to shoot accurately. Shotguns  are one example of a smoothbore and may be used to shoot "shot" as well as roundball, so long as they do not have a "choke",  (a narrowing of the bore) at the muzzle. This "choke" helps to control the pattern of the shot.
Muzzleloading basics- #3 Projectiles
Muzzleloading projectiles should always be pure lead, & come in a variety of shapes & sizes. A roundball is wrapped in a lubricated linen or cotton cloth, which acts as a partial gas seal. The conical, elongated bullet is coated with a lubricant rather than a patch, & when fired the skirt expands to fill the rifling grooves.
Round ball patches should be tightly woven 100% linen or cotton. The thickness is determined by the size of the ball & the depth of the grooves in the rifling. Generally, determining the optimum patch thickness is a trial & error process, just one step in developing an accurate load combination. Never use synthetic material for patches as they may leave a residue that can build up and create a barrel obstruction.
Patch lubrication is used to seal patching against burn thru, assist in cleaning the bore & to improve accuracy. It can be a commercial product, oil, lard or even saliva.
This is the proper sight picture for a "6 o'clock hold". The sight picture for a "center hold" would be identical, except the front blade would bisect the circle.
Muzzleloading basics- #4 Accoutrements
These are just some of the many accessories to the blackpowder firearm. Included are- powder horn for carrying powder, powder measure to measure the charge, ball starter to start the ball down the barrel, patches, patch knife to cut patches to size, cleaning patches, priming horn to carry priming powder for flintlock ignition systems,  (or caps for percussion), round ball or conicals, and the possibles bag or shooting pouch to carry it all in.
Also included would be various tools such as a nipple wrench, vent pick, screwdriver, capper, cleaning jags, ball puller and patch worm. Add to that extra nipples or flints, leather scraps for flint pads, lubricants, solvents for cleaning & an oil dropper.
These are only the basics, each individual shooter almost always comes up with additional items deemed absolutely indispensible, to that particular shooter.