Do you seat your bullets so their flush to the cylinder or some distance from wherever this forcing cone is? Do you make test loads for seating depth?
Seating bullets flush with the front of the cylinder is a bad idea and is just asking for problems.
From the questions you are asking, it appears you are lacking some basic information about how a revolver works and what some terms mean.
First, the forcing cone. This is the "beveled" area at the rear end of the barrel. The slight taper "forces" the bullet into alignment with the bore of the barrel as it enters.
Next is the cylinder, which contains the chamber (where the loaded cartridge physically fits) and a section ahead of the actual chamber which extends from the chamber to the front edge of the cylinder. This area is called the cylinder throat.
The throat is simply a smooth "pipe" the bullet moves through on its way to the barrel. However the fit of the bullet in the throat is an important thing for accuracy.
The next point you're missing is how the revolver acts on the rounds in the cylinder during recoil.
Unlike magazine fed repeaters, the revolver holds the cases by the rim and when the entire gun recoils the cases are pulled back with it. Inertia of the bullet tries to hold it in place, so the effect is that recoil pulls the case away from the bullet. This is called crimp jump or bullet creep. The effect is that the bullet seems to move forward in the case, and in extreme, out of the case entirely. This can result in the bullet sticking out the front of the cylinder, which jams the gun. That's why you don't seat bullets to the front edge of the cylinder.
We PREVENT that by using proper neck tension to hold the bullet AND a crimp. Usually a roll crimp into the cannelure or crimp groove of the bullet.
The proper depth to seat the bullet is so the case can be crimped into the middle of the crimp groove. This allows for very small variations and still yields a serviceable round.
The way to do this consistently is to trim all cases to the same uniform length then adjust your dies for that.
Do I make "test rounds" for seating depth? Not generally. When I change bullets I just use a careful trial and error method, starting with the seating stem backed off a bit, then moving it down in small steps seating the bullet deeper and deeper in stages, until it is seated to the proper depth for crimp, then I back the stem off a half inch or so, and adjust the die body to get the desired amount of crimp, then, once that is set, run the seating stem down to firm contact with the bullet and I'm ready to load, seating and crimping in one smooth, easy step.
Some folks will say there are advantages to seating and crimping in separate steps, and for some things there can be, I seat and crimp rifle rounds as separate steps, but I've been doing it in one step for revolver rounds since the 70s and if I do my part right setting it up, it works just fine.
Carefully read the "how to" sections of your loading manual. When you have questions (and, you will have questions) TFL is a good spot for answers. There's a lot of us here who have been doing this for a long time, and some of us even know what we're talking about!
