Quote:Would it be safe to just start at 3.2 and work up?...That would be the safe way to start...I usually load five rounds of each powder charge (.1gr increments), starting at the bottom and working up...Providing that they function the action, keep a close eye on the extracted cases before moving up to the next one..If you concentrate at reasonable ranges you will also find your most accurate and it may not be at max charge level...
You need to pull up a Burn Rate chart on powders if you are going to change powders so you will have an idea as what to expect...Bulls Eye is a relative fast powder,,,,VV powders can be quite a bit slower...On the fast powders, a very small amount can produce some dangerous conditions pretty quick...
HERE is a pretty decent Burn Rate Chart...I like it because it also compares one brand to another in the event you need to substitute....
9mms, as most other straight wall pistol rounds will head space on the rim of the case, rather than the bullet...If you plan on loading a lot of them (very seldom do they need trimming), a case check gauge is a good investment...usually $10-15..Just stick with the published OAL for the cartridge and you will be fine...
I have one .40 s&w match barrel that is fully supported and so tight that reloads on cases that have been shot out of a Glock (or other non-supported chamber) will not function, even though they pass the check gauge test..I have to keep all of that brass separate from the rest, and mark the boxes accordingly..
