libertyman777 said:
So my next question is, how far can one safely stray away from a proven powder. I see that in the AA load data that 2700 and 4064 are suitable. IMR 4064 is pretty far removed on the faster side of H4350. So would every powder listed on the burn chart between IMR 4064 and and H4350 be okay to consider?
Yes.
No.
Sort of.
This is something you'll learn from experience and a lot of reading.
For example:
H1000, Reloader 25 and Retumbo are all slow powders that are proven to work well with heavy bullets in 338 Lapua.
Can you load that cartridge with the faster H4831? Sure you can. You'll need to reduce the charge (as it compares to Retumbo) a LOT.
Can you load that cartridge with the still-faster H4350? Sure you can. You'll need to reduce the charge even more.
Can you load that cartridge with the still-faster Varget? Probably, though I don't kow about that one for sure.
At some point, you'll have reduced the charge weight (due to the faster pressure rise) so much you'll be in danger of powder deflagration (basically detonation), rather than a nice controlled burn.
Where is the deflagration point? It depends on powder and the cartridge you're loading. Many powders will indicate how far UNDER you can charge cartridges with that powder. In general, it isn't that much!
A famous example of a good powder to under-charge cases with is H4895. Hodgdon will tell you H4895 is safe down to 60% the chargeweight of their *maximum* published load.
An infamous example of a BAD powder to undercharge with is Unique, which is credited for blowing up many pistols due to undercharged cases.
Titegroup is another exmpale of a powder that is GOOD at low charge weights. For example, I use it to load "plinking" loads for my SW500. Whereas over 50gr of that powder could fit in the case, a max charge is actually ~17gr....and 17gr doesn't take up much space in there at all!
Keep reading. In the meantime, stick with proven published data.