Just remember, Quick Load is not a loading manual. Its better!
Explain, please, how a computer program that can only "predict" is better than data obtained by actually shooting real ammo in real guns.
Real world data doesn't match Quick load prediction? sorry, life is like that sometimes.
Actual ammo and actual guns vary. Often the variation is fairly small, this is why reloading data works AS A GUIDELINE. Sometimes the variation is much larger.
The only 'correct' data for your gun is the data you work up and test IN YOUR GUN, with YOUR COMPONENTS.
While you will see "conflicting" data from different sources, it really isn't "conflicting". The conflict is a false assumption. The data reported is an honest and accurate account of what they tested.
NO two or more different sources can test the same identical guns or ammo. And even if they could, it would be different from what you and I have in our hands.
So using the theory all 230 JHP bullets are created the same what is the maximum safe load and what should the COL be? I want to know.
First off, you shouldn't use the "theory all 230gr JHP bullets are the same", because they aren't. You're asking about differences in seating depth affecting pressure, and it does, but there are OTHER factors to consider, as well. One big one is the length of the bearing surface of the bullet. (that part of the bullet that is engaged by the rifling) Another factor is the material the bullet bearing surface is made of. (lead, plating, regular "normal" copper jacket, harder or softer than "normal" jacket, etc.)
These things all have an effect on the pressure of a load, as well.
The maximum safe load and COAL is what YOU determine, for your gun, by carefully testing different combinations, until you find it.
SAAMI specs and limits are industry limits, intended for manufacturers, and meant to be safe in EVERY gun. Nothing wrong with that. and they will be safe in your gun (absent some extraordinary conditions).
But there is no hard and fast rule or limit for your gun (and ammo) except what you test in your gun. Think of it somewhat like a speed limit on the highway, (somewhat like, not exactly like), you can drive 55, and be mechanically safe, tis the posted limit. Maybe your car can do 80, and still be mechanically safe. Maybe my car will blow a rod if I do over 65, or I've got bad tires, so I only drive 55. Book (and internet) say 55 is safe. Beyond that, you're on your own.
Doesn't mean 80 isn't safe in your car, with you driving, only means they won't say its safe, because they don't have your car, or you driving, to test your safety.
Like the pirates say "arrr, they aren't rules, more loike guidelines, really..."