Yep, if you fool around long enough with enough rifles and manuals, you will run into scenarios that are only determined by the chronograph.
I ran into this with a custom barreled 7mmRemMag about 7 years back.
Long-throat 7RM I now shoot 69gr of RL22 under a moly 160AB in this rifle for about 3,000fps. That's 6-8gr above book max, depending on the manual. The moly maybe eats up a grain or so of that, due to the loss of friction, but it is still not a load I'd drop in any other rifle. This one has a lot of freebore, and as a result, requires powder charges close to 7mm Weatherby levels. It shoots so well, I don't want to mess with getting a new chamber cut, so I live with the jump and the larger appetite for powder. Live and learn.
This is why it's tough to say there's a "standard load" for any chambering that is up near top-end levels. Two rifles in that chambering may be able to tolerate that load, or they may not. It's best to work up over a chronograph if you think they are warm loads.
I saw an interesting one just this last week when looking for data. I'm tinkering with a deer/hog load in 338WM, something that might kick a bit less than my standard 200gr/65grRL15 load. I have heard about 57-60gr of H4895 being good with 200gr bullets and making 2700-2,800fps. As I have some 185TTSX bullets coming, I wanted to see how the lighter weight bullet factored in on that front when it comes to recommended powder charges, so I went to Hogdon's online data. Max load shown for the 200gr Speer with H4895 is 62gr, with the 210gr PT at 60gr. That makes sense, with the PT being a bit heavier and having the differing internal structure. But the 185TSX has a listed max of only 59.5gr. That's a half-grain lower than the 210PT load with a bullet weighing a full 25gr less. Likely has to do with case capacity and the length of that copper 185, but still, it shows that not all bullets behave the same way. Some powder charge/bullet weight combos are obviously not just plug-and-play with any bullet of your choice.
