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Old 05-08-2016, 09:20 PM
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Alk8944 Alk8944 is offline
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Several propellants sold under both the Hodgdon and Winchester brands are manufactured by St. Marks Powders, a division of General Dynamics, in their plant in St. Marks Florida. Among these are H-110/296, and, HP-38/231.

I had a conversation several years ago with an engineer at St. Marks specifically about H-110/296 when there was still disagreement about whether they were identical. This was before Hodgdon became the distributor for the Winchester brand! He finally admitted that they were absolutely identical! I asked if there were any other powders they manufactured for Hodgdon/Winchester that were also identical, and his answer was NO. However, since Hodgdon has become the distributor for Winchester Hodgdon now claims that HP-38 and 231 are, in fact, identical. I can see no reasonable to doubt what Hodgdon says!

Now, let's address differing data in the same manual for each of these pairs of propellants. Logic would say that if identical that developed data should be identical, subject to very small differences as a result of lot-to-lot variation! In the Hodgdon manuals you will see that the data is identical as would be expected.

But, go to Sierra of a few years ago for example, or Speer, Hornady, etc. You see significant differences between H-110 and 296, or H-38 and 231. Is this necessarily because they were that different, or simply that loads were developed simply by the technicians "instinct" (gut feeling), "pressure signs" (hardly dependable at rifle pressures, worthless for handgun cartridges!), or because they did not actually pressure test all of the data as most people seem to believe! The hard, cold, fact of the matter is, while some data is pressure tested, that the majority of loads are calculated from a base pressure level with that powder and bullet! Why do you think, Sierra for example, shows loads to achieve a specific velocity, and not a simpler minimum/mid/maximum load like Speer does? Have you ever noticed that the Speer "Starting load" is usually simply their "Maximum load" minus 10%?

A prime example of the fact that much data has not been tested in the "magic" Speer Number 8 manual with some absolutely terrifying data for .38 Special, 125 gr JHP, and SR-4756! I won't repeat the data, but at the same time IMR was publishing a maximum load for this combination, at 15,000 PSI, that was less than 1/2 the Speer load. If I recall correctly the Speer starting load was more than twice the IMR Maximum! And this was supposed to be a Standard Pressure .38 Spl. load as the Speer #8 was published before the +P standard was established in 1972!
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