Your 50.0 grain load is about what I would expect from a 308/180/20" at SAAMI pressure. I had a Ruger UL in 308 and it ran 28-2850 with 150's, 2650 with 165, and 2575-2600 with 180's using max charges of H 4895 and Varget.
I've also ran 150 and 165 in a 15" 308 Encore and lost ~ 75-100 ft/sec from my 20" Ruger.
I mean no disrespect to you but we definitely see things much differently as I tend to rely on pressure tested data over QL calculations. I have a spreadsheet version of QL and use it alot to develop pressures/loads for wildcat cartridges I have for my Encore/Contender. I tend not to rely on QL or any other mathematical model but use linear interpolation of known data and case capacity.
As an example, the Re 17 load data I have from Alliant for the 308 shows a max charge of 48.6 for a 180 and COAL of 2.800. They also list 50.0 as the max charge under a 165. Both charges are compressed but would venture pressure is close to SAAMI. I also make the assumption that powder companies are developing load data in full compliance with SAAMI. I would not be comfortable with the loads you list.
