Your question is one that will spark a lot of contrversy, and especially after my stated opinion, as follows.
I have been loading for almost 30 yrs. using a method I learned from the Speer #10 reloading manual, and have never experienced problems. So my first suggestion would be to buy a good reloading manual that lists SAMMI recomended minimum COAL's for various bullets. I'm stating this first off because, there are a lot of us old timer's that have found a method that works for us, yet may not be completely in line with the books. If you rely on what we have to say, you'll likely find yourself more confused, than informed. With that said, I'll continue with caution, and explain it, as I understand it, according to my #10 Speer manual.
The Speer #10 says that seating as close to the lands as can be accomplished without touching the lands is the recomended method to determine proper seating depth. Additionally, it is stated that the slower burning powders will help add to accuracy and velocity, while maintaining well managed pressures within SAMMI recomendations. This does not mean it is reloading law to load in this manner, by no means. But because this is what I learned early on and have used as my method, is why I believe I've had excellent results and experiences with hand loading all these years.
There is so much more to it than that, and that is why I so strongly suggest you buy a book or two, and read them cover, to cover. I suppose a video is another option that wasn't available, at least not to my knowledge, back when I began reloading. But whether you use a video or what ever resource, you still need some books that will provide you with the answers to questions you'll have. Back in the day all we had were books, so getting information, or more specifically answer's to questions, forced those of us form that place in time, to read our reloading books. The world of hand loading has become more complex in part due to the many changes that have been made to data, and other pertinent elements of the process since then. Equiptment used to establish SAMMI specs. has become more accurate, the number of powders available to use has increased by leaps and bounds, and bullet choices are immense. The Speer #10 manual is pretty obsolete regarding the cartridges in it, powders, and even a good deal of the data contained in it has changed. But I still find it a useful tool in providing me with good sound loading advice regarding safe methods.
Good luck and enjoy your SPS.
