Historically, the focus of load development has been on velocity. There is/was lots of lip-service given to "accuracy", but when the first thing one looks for is a
max velocity "that gives the smallest groups", the truth is that velocity is "first" before precision ("accuracy"). It is my belief that this search for velocity is a hang-over from the days of transition from black powder and cordite to smokeless. (Let's not argue whether it is or not, that's just my opinion.) That search for the fastest velocity caused the "normal" process of "working up a load" to start with the hottest load a rifle would shoot without showing "signs" of excessive pressure, THEN "fiddling" with charge HOPING a "good group" could be found without having to "drop" the velocity "too far".
I, having grown up on the likes of Jack O'Connor, worshiped at the Speed Uber Alles altar. That was among the many 'things' in my life that I got taught that was wrong, and among those I had to relearn through first-hand experience. I've spent the better part of 40 years looking for "predictors" that would allow me to develop loads quickly and inexpensively. The "ladder test" is a good method that indirectly addresses the fundamentals of some of ballistics - internal, external, and terminal.
What I have come to is application of Optimal Barrel Timing theory
Optimal Barrel Time Paper to locate a "good" exit time for a bullet and load. Once that timing node is found, I fine tune the load with fine incremental adjustments to
seating depth. Velocity/charge is a non-issue EXCEPT for making the selection of which timing node to use.
That said, I will add that there are people that hate Optimal Barrel timing theory so much that they are practically willing to start a fist-fight whenever someone suggests its use. Personally, I "keep" things that work for me, and discard those things that don't. OBT "works" for me, and in fact has allowed me to assist people that are a great distance from me in developing excellent loads with a minimum of time, money and reloading resources spent. THAT's part of what "works for me" means to me.
Let me explain a little why I consider charge to be
relatively insignificant. If one selects ANY
reasonable charge, OBT (and my personal experience) suggest (strongly) that excellent precision can be had simply by adjusting the COAL (seating depths). The range of seating depths that should be considered are
substantially larger than most people TALK about using. The range within which it is almost a certainty that a precision 'sweetspot' will be found is from "right on" the lands, to off the lands by as much as 0.150" and sometimes even more. Most people TALK about adjusting seating depth in increments of 0.005" and some even say 0.001" (which frankly is absurd in terms of repeatability). In fact, 0.005" is the absolute realistic minimum increment unless you are using precision reloading dies (and I mean REALLY precision), AND have a
precision benchrest rifle.
If history is indication, I'll get told how "wrong" I am about this. If you (the editorial "you") are so inclined to "correct" me, spare us both. I have no 'dog in this fight'. I couldn't care less whether ANYONE might choose to use the methods I have chosen to use. As I said, the methods I use are those that "work" for me, not ones I have READ work for someone else. "Working" for me means getting me to tight little groups as quickly as possible with the mininum expenditure of powder, bullets, primers, and money. I find that adjusting seating depth accomplishes that better than adjusting charge.
ATB
Paul
(optimal barrel timing?), P.S., remind me to put a lot of distance between us if I ever come back as a member of a hunted species!
... Steve.
