Shawn: Review a bunch of data from various sources,as many as possible and note correlations between charge weights and velocities...understand that your rifles may differ from the barrels used to aquire the data you are reviewing,and often by a substantial margin.This is true of any caliber, not just the 7 Rem mag.
Get a weighted "average" on the velocities and charge weights.Start low and work up,with a chronograph.Generally the faster you are going, the more pressure you are generating with a given powder....another powder may generate the same velocities with acceptable pressures ,ie be better suited to the combination you are using than another.
Without a chronograph you are working in the dark.
Try to use no more than one or two powder/bullet combos at a time to avoid jumping all over the place...this can lead to confusion and false results and no real conclusions.
When you think you have reached max for a trouble-free hunting load,take ten cases,and use the same max charges to check primer pocket tightness for several loadings in those ten cases.If your primer pockets stay relatively tight,and are absent of high pressure signs you are likely OK.
Sometimes this will correlate to listed data,and sometimes it won't.I would not be concerned.This is common with any cartridge; not just the 7 Rem Mag although the printed data does jump around.
What I do after all the other stuff above is done, is load a batch of ammo with that load and shoot year round;summer heat and winter cold,and watch the load.
This may not be perfect but is as close as we can get without pressure equipment for our rifles.
I have loaded for 7 Rem mags well into double figures.Using these methods I have not had so much as a hiccup with the cartridge,and great field performance from it as well...I can't even remember even getting an ejector mark on a case,and certainly never a blown primer.
I know the 4350's work in the 7 Rem Mag and some savy guys on here use it.I prefer something slower myself, but your work will tell you what works in your rifle.Good luck.
Welcome to the CF.
