Originally Posted by
MT Gianni
Part 2
Component Selection
Bullets
With conventional cast or swaged bullets, you must match peak chamber pressure to bullet hardness. If you have a Saeco or other hardness tester, take readings on nose and base of several examples – discard any unusually low readings (these indicate porosity, which is common on sprue end has nothing to do with hardness), then average the remainder. If you have some way of estimating peak chamber pressure (if you understand a few variables, QuickLOAD, 800-451-3550, works splendidly) look for a load generating at least 1500 times the Brinell hardness reading (Saeco supplies a conversion chart) – e.g., a Brinell 10 bullet requires about 15,000 psi to properly obturate, significantly less peak chamber pressure can result in gas cutting; significantly more peak chamber pressure can result in pressure leading.
Having tested dozens of bullets rated by commercial manufacturers as "Saeco 10", I have learned to distrust their claims. Almost universally, those run closer to Saeco 7! Even this is too hard for some milder loads. The problem is this, when the manufacturer lies about bullet hardness it is difficult to guess needed pressure!
Modern wheel weight metal alloy is softer than in days gone by. Therefore, our modern wheel weight derived bullets tend to be significantly softer than our older wheel weight derived bullets. In addition, modern commercial-cast bullets tend to be harder than any wheel weight castings (unless those are heat-treated). Furthermore, note that cast bullets tend to harden or soften with age – depends upon alloy and initial cooling characteristics.
For what it is worth, more revolver barrel leading results from use of too mild loads than from use of too hot loads – particularly when using commercial cast bullets. Swaged bullets are another matter entirely, those require very mild loads and the powder charge range – from too mild to too hot – is often only a few tenths of a grain.
Powders
As to midrange load powders, I have several favorites. While there is nothing wrong with Bullseye or Unique, I prefer cleaner powders. Perhaps the cleanest and best for this type of load are Red Dot (particularly the new version), 700-X, Clays and Solo-1000. Because it is a single-base powder and therefore leaves less smoky residue when burned at lower pressures, I have personally gravitated toward Solo-1000 (a flake powder from Accurate) for all midrange revolver loads.
Primers
With these powders, I prefer Remington's 1½ (small) or 2½ (large) primer. This is among the least brissant (explosive force) but hottest (amount of heat generated) of readily available primers. Such combinations of primer, powder, bullet seating depth, neck tension setting and crimp, can produce spectacularly clean and consistent loads.
A few notes of caution
IMR does not test any of their nominally shotshell intended powders at pressures greater than those found in shotshell proof loads (about 20,000 psi). Therefore, despite the fact that many loading manuals have listed various IMR powders for use in pistol and revolver loads, it is patently unsafe to use any such powder in any load where peak pressure might significantly exceed about 15,000 psi – this includes most pistol loads and all magnum revolver loads. I fear the same is true with Accurate shotshell powders but at least their single-base shotshell powders will tend to be better behaved (more apt to demonstrate lot-to-lot uniformity) when used at higher pressures. I do not know about Hodgdon shotshell powders. For safety sake, if the load you are using significantly exceeds nominal shotshell pressure and you prefer to use a shotshell-designed powder, keep in mind that (as far as I know) the only brand readily available in the US that is always tested for lot-to-lot uniformity at typical rifle, pistol and revolver pressures is Alliant – Red Dot, Green Dot, Bullseye, Unique, Blue Dot and 2400.
Equally, note that primer substitutions have been proven to sometimes radically alter pressure – this is not unique, ballisticians tell horror stories of customers who haphazardly substituted primers and ran into king-sized problems – for example, combining a milder than suggested primer with Accurate #2 in a 9mm load and doubling pressure! Moreover, neither you nor anyone else can reliably predict results of any primer substitution! Use of a "hotter" primer can result in lower pressure and use of a "milder" primer can result in higher pressure – any result is possible and all have been observed. It is a unadulterated and unequivocal fact that anyone who professes to believe they can predict even the general trend resulting from such a substitution will have already demonstrated sufficient ignorance of reality as to make the results of any handloading decision based upon their further proclamations fraught with peril. Often such predictions hold, just as often those do not.
In Conclusion
As an example of just how good loads adopting these principles can be, with a commercial-cast 240-grain Keith SWC loaded in the 44 Magnum and seated for a slight roll crimp over the driving band, 6.9 grains of S-1000 ignited by the R-P 2½ primer produces just under 1000 fps from my wife's Hawes. Standard deviation is in the single digits (comparable conventional loads typically generate three times the average shot-to-shot velocity variation). Accuracy is better than I can measure with my waning skills and powder position effects are quite modest. However, perhaps the most startling characteristic of this load is that it is so clean that it is quite difficult to tell that the gun or case has been fired, either by feel or by appearance – after firing 100 of these rounds the revolver is still clean!
I could ramble on further but I hope I have covered the basics here. If accuracy and dependability are your goals, consider the above areas.