Are the powders listed in reloading manuals by a manufacturer, for a specific bullet tested,the only powders tested for that bullet,or are they the best performing powders of various others tested?

I THOUGHT OF IT AS FASTEST TO SLOWEST POWDER BEST SUITED FOR THAT CALIBER AND BULLET WEIGHT THAT WORKED INSIDED OF A MININUM AND MAXIMUM PRESSURE RANGE. usually with one powder being the most accurate for there test rig.
sorry about the caps didnt want to retype.
dave

I have seen different powders tested for the 270WSM in some manuals that were not included in others.

My understanding is that they are suitable powders for that bullet weight. If you look in different manuals you'll find more powders listed at the same bullet weight. With all the powders avaliable out there now, a reloading manual would look more like the tax code book to put data for all the powders in it. The only powders I use today that I couldn't 40yrs ago are RL 22, yup, that's it! Everything else still works well enough that I don't change a lot. Oh, I lied. I don't use H4831 anymore, I use H4831SC!

To give an example,Reloader 25 is used in the Swift manual for the 270WSM 140gr bullet but it is not used in the Barnes data for their 140TSX.Has Barnes tried R25?

It may be that the barnes bullets are of a diffrent construction, with that its only speculation why barnes didn't list a load for that combination and swift did.

Some other considerations they may have
Time to test every powder that's available in the world
Powder inventory on hand
Space in the manual

If they test with powders that have a burn rate slightly above and below that of the powder you intend to use, you could extrapolate that your min/max charges would be somewhere between those of the powders tested.

quote:

Originally posted by shootaway:
...Has Barnes tried R25?

The only way to know is to call them. I just looked through my really old Barnes #1 and it doesn't even have their phone number in it. Maybe their ads would have it, or their web site.

You are getting a lot of good guesses at why it may not be included. Might be they realized how erratic the Pressure becomes with the "RL Powders" in some cartridges as you approach MAX. That's what they did when I tried them.