Don't get me wrong, loading manuals are an invaluable resource for the beginner through master reloader. What they do not tell you is the whole world beyond basic charge weights for bullet/cartridge. They are the Chiltons Auto manuals of the cartridge reloading world. Once one understands the principals of volumetric efficiency, expansion ratios, powder burn rates as they relate to bullet weight and bore diameter, frictional coefficients, barrel twist rates and how they affect pressure..........and a few other basic principals of internal ballistics, one can deviate from the beaten path with relative safety.
Extended flash tubes was a very interesting experiment, which taught me a few things about internal ballistics. Without going into all the stuff involved, suffice it to say they have a certain merit.........but what a pain in the a$$. Not pushing your entire powder column of up to 100 gns, down the barrel ahead of ignition, changes the pressure curves and definitely increases velocity. Although I never did enough to prove it, it must also dramatically reduce throat wear. What it did not do, which I did expect, was to reduce peak pressure, which led me to deduce that peak pressure occurs around the time the last solids are turned to gases and it is determined by powder burn rate and quantity in a given bore size, not where it occurs in the barrel. There were a few other interesting outcomes, noticeably less muzzle flash, but perceivably more noise. This tells me that the powder is being burnt much more efficiently throughout the bullets travel down the bore, but that peak pressure occurs much closer to the muzzle. Although I was not using a heavy barreled rifle, it occurred to me that maybe I should be if I was moving the peak pressure significantly down the bore to a much thinner part of the barrel.
Anyway, there is a whole world beyond loading manuals that has not been totally explored, but that does not mean loading manuals are worthless by any means, any more than recipe books or Chilton's manuals are........they give you the solid basis for any experiments beyond where they leave off. And with out this basis, every experiment would have to start at square one...........PO Ackley takes one well beyond loading manuals but unfortunately is so out dated that although his principals and ideas are still relevant, new powders change a lot of his outcomes. But his theories and findings are still valid and very much worth knowing.
I truly wish I had more time and money when I was younger, and had this insatiable thirst for knowledge of internal and external ballistics. I may have actually discovered something new or truly different.............but alas such are the regrets of age.
