Does one first choose a powder?
How about choosing a moderate charge?
Maybe you choose the bullet first?
These are representative questions that I suspect really frustrates cast bullet shooters, young and old (like myself). After twenty years of reloading with good, bad, and great results; but always tollerable groups after minimal experimenting, I would like to truly understand the relationships between them and the order of process steps, involved in developing the best load for one gun (a revolver). And after reading literally all of the reloading manuals including Lyman's Cast Bullet Manual, this information is missing I believe.
Maybe there is no truely "right" process because no one variable is "independant" of all others and the only way is to shoot every permutation of the pertinent variables.
Here is another way to wrap your head around the dilemma;
I have before me three lead bullet candidates, all historically good performers and I have large quantities of each, all unsized and all over my cylinder throat diameter. I eliminate one variable, sizing diameter, because past experience tells me that the popular method of matching diameter to throats works well. So I size them all to .0005 under throat diameter.
I then make sure that all throats are consistent among themselves and universally over groove diameter by .001. This then eliminates another variable and locks in the generally accepted relationship among these three features.
I then choose a historically good powder and moderate charge for my cartridge, which seem to give good results at all places in the pressure spectrum. Here I may be making a mistake but I am tryiing to eliminate two more variables; powder type and charge. So I hover somewher in the middle. Now, we will come back to this decision later as I am not done just yet determining the optimum charge. I am just done for now.
I shoot multiple groups (machine rest and consistent conditions) with this one charge, and with each of the three bullet candidates (I have also chosen and standardized things like crimp severity, seating depth and lube which I am hoping are not going to impact my results as long as I, once again, stick with reasonable reloading practice), and collect and summarize the data.
Here's the meat of the question;
If the resultant groups, from worst to best, are bullet c, then b, then a, and I then change one of the above mentioned variables like reducing or bumping the charge or going with a similar chamber pressure load but from a different powder, will the resultant accuracy data still likely be in the same order for these three bullets? i.e bullet a is still most accurate. If so, then I can cut my load development by two-thirds by continuing on with only bullet "a" and NOW start playing with powders, charges (I told you I would come back to this.), crimp severity, primers, seating depth, casting alloy, and on and on and on. In reality I suspect all but chamber pressure (and resulting velocity) and maybe powder burn rate are fairly innocuous variables.
If I am wrong and the resultant accuracies will likely be different, then where does one begin? What is the true process for developing an accurate load? What can be chosen with the confidence that if it is altered, the results might move but they move uniformly among all your other candidates (among the three bullets in the above example). Keep in mind that I could have just as easily chosen three powder burn rates to compare, keeping everything else consistent and once the most accurate "burn rate" was identified, I moved on with this burn rate alone and continued my load development because I was confident that this burn rate was optimum regardless of where I go from here in my load development.
Thoughts?
Ed
