Get some drops at 300 yards, 500 yards, 700 yards and 1K+. Enter all of the environmental conditions into a ballistics computer. Enter the factory BC into the computer and then began running the program with 50 fps velocity increments of your best estimate.
When you find a combination that comes close to hitting your 500 yard drops as well as the 1K+, you then tweak the BC a little lower (usually) and the velocity lower or higher as needed. When you find a velocity and BC combination that passes exactly through ALL of your measured data then you save that for the future. And when you encounter different environmental conditions you use your velocity and BC just as if you had measured it (in fact you have measured it).
To do the process accurately you MUST have at least three data points. If you only use your 100 yard zero and a 1K+ drop you can get a infinite number of incorrect answers. There is only one true answer and you can find it with three points. I prefer four or five points being as sometimes the center of my groups are not shot in as well as they should be due to my less than artful skill with a rifle. What you are doing with the process outlined is iteratively solving by approximation an equation with two unknowns. The reason I say two unknowns is that the BC of a bullet will seldom be exactly what the manufacturer says. Small changes in the BC value change the middle part of the trajectory curve so just using velocity changes will not get you a perfect match.
The process above is what I use all of the time and before there were computers I used graph paper. I do not have a chronograph and have no need for one. Of course, I have reviewed thousands and thousands of pages of supercomputer output data and get some enjoyment from spending my day looking at numbers and graphs and my method comes very easy for me.
Well, according to Hogdon's On-line Reloading Data Center the max load for a 300 RUM with 200AB's is 92.5 H-1000 and their velocity for that load is 2975. So......your guess is as good as mine.
Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 103 93.00 3167 4456 85573 11691 100.0 1.153 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 103 93.00 2910 3761 56677 12631 99.4 1.362 ! Near Maximum ! </pre><hr />
You are over your max pressure. Max pressure is 64997. This could be why the SMK's didn't shoot as well...
thanks for all the info, ok, apparantly I might be loading a little hot. I am wondering why there are no extractor marks, no sticky bolt lift at all, primers are fine, etc, etc, no signs of excess pressure...
I worked up to that load and it ended up being the most accurate, so I wanted to use it, but maybe I shouldn't...???
I have shot the smk's over lots of differant powder charges(h-1000 and retumbo) all a lot less than this charge, and came up with less than desirable results. I would rather shoot the 220gr smk's, but no luck yet. (the only halfway decent loads I've gotten with the 220's is with retumbo, 83, 85, and 87gr loads all showed some promise.
I guess maybe I should start looking for another load, it kind of sounds like. is everyone agreeing that this one is to hot?
thanks again for the info!!! I will add, that I am somewhat new to the reloading game, but I have been able to find some great loads for my 223, and 243, but this 300 is a little elusive as of yet.