I use a lot of Lee stuff too. ... My presses, scale, powder dispenser, and 2 of my dies sets are all Lee.
Well, that explains a lot! Sorry, there's obviously no help for you...
published velocities in a manual,
I look at them with a jaundiced eye my own self! In my experience they tend to be a little optimistic. However, I think you can get a fair estimate of what your velocity based on published data with a little interpolation. If I'm doing what I did for the 30/30, grab a powder and bullet and pick a starting charge from a table, I review all the sources I have available and compare particulars with the rifle and circumstances I will be using. i.e. velocity from a 24 in barrel vs. the 20 inch I will be using, and adjust the published velocity accordingly. I also subscribe to
Handloaders on-line service which gives me a bunch of loads and their actual velocities shot by whom ever. But the end result is still just a rough guess.
and I don't (yet) own a chronograph.
You are missing one of the great joys of life!
You can still work up great, accurate handloads without one, but they make the process more interesting. I am now beside myself with desire for another instrument that is, for the moment, unavailable to the average handloader... what I call the PPMD (Personal Pressure Measuring Device).
Is starting data woefully underpowered compared to factory loads?
Okay now, you got the "liability warning device" going off in my head!
What is "underpowered" is a pretty subjective question. Especially when we have no idea what the power level is of either load. I would imagine the starting loads are capable of killing a deer even if they do develop a bunch LESS velocity/energy then a factory load.
Is max data generally close to factory or well above it?
I think that most factory ammo is pretty good stuff nowadays. In most cases that is. Maybe even hard to beat velocity and accuracy wise. Especially in the velocity arena when discussing the "Light Magnum" type loads.
Is factory generally 30% of the way between or 80%?
I don't think there is a general assumption to be made in this regard. At least I wouldn't want to make one. If I were to take a factory round, come up with an average velocity, then take a handload and come up an average velocity for that handload I could say, generally, what % one was of the other for that factory round (from that lot number) as compared to that handload (using that powder lot number, primer and case) only.
In short, it seems you are looking for hard and fast assumptions you can make in areas where there are none to be made. Maybe even in areas where it would not be SAFE to attempt to make them!
Does it vary by load manual and if so what is a good one to look at?
Usually; again a generality. I have Nosler, Sierra, Speer and Lyman manuals plus whatever booklets different powder manufacturers put out. I also use the aforementioned on-line site a lot.
Or is there not even enough consistency to generate a rule of thumb.
BINGO!!!
Well, consistency may not be the correct word since that's what most handloaders strive for! The only good rule of thumb is the original one: You can't beat you wife with a stick larger then the circumference of your thumb.!
I have no problem checking progressively increasing charges up to that point to verify their safety
That's it, start low and work up... slowly!
I just don't consider it a worthwhile project if have to test 2 dozen different powders and 6 kinds of bullets to find a sweet spot.
I usually just pick a powder based on whatever reason is important to me at the time. Tim had a good 338/06 load using BL(C)-2 so I got some and naturally want to try it in other applications; I've used a lot of IMR's and now want to try the reportedly more temperature insensitive H's; I got a good deal on whatever, now I have to find a use for it; If I try it and Don't like it, I'll try something else. Matter of fact, if I try it and like it I'll try something else!
Bullets are easy. Since I guess the remainder of my hunting will be limited to our deer, I have settled on and routinely use Rem Core Lokts.
(and to my fault, have a short temper)
I always thought I was a violent person by nature... woulda made a great "berserker" in the middle ages. Thankfully I found out I was just psychotic with a chemical imbalance. And they got drugs for that!