1) As far as pressure signs, I have measured shells before and after shots and have standard variation the same as standard pressure cartridges.
2) Primers are not showing signs of over pressure.
3) Just because there is no posted load data with a powder that I am using does not mean it isn't a recommended powder.
4) All I did was look at powder burn rates and pressure rates and started doing a little branching off. 4000MR is used quite a bit in the 300WSM Cartridge.
5) Shooting a low pressure loaded with 4000MR achieves better velocities than a lot of "recommended" powders loaded high pressure.
Again, this isn't to play safety police, but to inform of what is actually happening.
1) "Signs" don't accurately report anything repeatable.
2) Read my pressure sticky, or the recent pressure testing of the large and small primer Creedmoor, or any of my other pressure threads. Assuming, which can get you into trouble, that there is no soft case issues such as Federal has; "Signs" can begin to reliably show when you are well above 70,000 psi.
3) That is actually what that means. When no one doing pressure testing recommends it, it isn't recommended.
4) The trouble with burning rate charts, is that they mean very little. Burning rate charts are done from a standard, typically bomb testing. So, when you actually put it in an application, things can change substantially. RL-17 in the Creedmoor is rather progressive burning, meaning it has a changing burning rate as the pressure changes. Use it in the 308, and there is nothing progressive about it, just a standard burn. I have also shared the traces for this in a few threads.
5) Unless you have used pressure equipment and measured/recorded the curve and pressures so you know it acts progressive, that is simply impossible. Pressure = Velocity. Faith and desire doesn't propel bullets, pressure behind them does. If you are getting higher velocity than a book, or expected calculation, it's because you have more pressure. Whether that is because your specific lot of powder has a different burning rate, or the application makes it such; you in fact DO have more pressure.