While examining the data listed in the Midway Load Map for 9mm Para, it was noted that the amounts of WW 231 listed for various weight projectiles is somewhat less that listed in other sources, particularly the data listed on the Hodgdons web-site. (Now contains WW data)

Any thoughts???

While examining the data listed in the Midway Load Map for 9mm Para, it was noted that the amounts of WW 231 listed for various weight projectiles is somewhat less that listed in other sources, particularly the data listed on the Hodgdons web-site. (Now contains WW data)

Any thoughts???

Look at 6 loading manuals and get 6 different loads. It is pretty common.

One reason generic tables get more conservative is that all bullets of the same weight are not alike and can be loaded to different max. Unfortunately some people act like they are all alike, so the publishers tend to use reduced loads that work with anything.

I like to have both the bullet manufacturer's manual and also one from the powder manufacturer.

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Science plus Art

The Midway Load Map data lists powder charges and pressures for each of the projectiles that they sell by specific manufacturer along with COL and attendant pressures in PSI. The curious thing is that the charge weights are lower and the pressures higher than in other sources using the same projectiles at the same or close COL. An example is the various Sierra projectiles listed compared to the Sierra handbook data, particularly with WW231.

The exact same load using different mfg bullets would be different velocity. The bullet shape, the configuration of the ogive, the length of the bearing surface will have more of less drag in the bore and will shoot different. That's why you need to have a half dozen loading manuals, then you work up the load to the spec's of your own gun.

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H Richard
SWCA1967 SWHF244