Aye.
ALWAYS START FROM PUBLISHED DATA.
If this is from bullet manufacturers, or powder manufacturers... just so long as it's from one of those sources. Books a great cause they're easy to thumb through, but many powder manufacturers also have website stuff.... I can dig up some links if it'd be helpful.
I really suggest the books. And since ya got one, picking up more as money permits is handy
. I've got a Hornady and a Speers book, and the non-reloading-table sections are very informative / helpful and are a
required read IMHO.
Also, always start your load towards the bottom / at the lower range of the charges listed.
Try to match bullet weight, jacket type (if any), and primer type (regular vs magnum).
Also it's seemingly contradictory, but heavier bullets take less powder. It's all about staying within pressure ranges.
Times to restart your calibration of powder charge / seating depth:
* Different weighted bullets
* New bullets from a diff manufacturer or different type from same manufacturer
* New primer manufacturer (ie: winchester -> cci, etc)
* New type of powder (kind of a duhhhh)
* New bottle of powder (powder batches might be slightly different, so a test batch starting at lower charge weights is good... or if you're making benchrest competition, ya should do this anyway for consistency)
The idea of starting with the lower charge weights and working your way up (a magazine or less at a time) - is you can find a charge weight that agrees with your pistol and STAYING WITHIN SAFETY LIMITS.
* with first magazine load if on a lower charge, always check the bore to make sure the round left the barrel. some people load light and this can be an fatal problem.
* check for signs of excessive pressure (you just hit upper limit and should back off a bit.. dismantling your current magazine's worth of rounds is suggested)
* No failure to eject
* No feed issues
* if you're shooting lead, you can possibly find a charge weight that causes the least amount of leading in your barrel
* which charge is the most consistent and accurate for your particular pistol (each firearm has it's own unique personality)
Also, I've noted that my Sig p229 doesn't behave linearly at all with powder charge weight. It's more like a curve / sine wave. Adding / removing 0.2 of a grain can make it quite unhappy... but if I add/remove another 0.2 grain it's back to purring.
Mudnrox, Annnddd... as SFG has pointed out... most of us here are willing to help out and answer questions and stuff