No not limited to mag length. I have a LA bolt stop and mags for my Tikka. I just read and went through all the info i could find on the web and most were loading to 2.825" to 2.800" which still would be within SA mag length. I'm 2.880" to the lands with the 155 scenar.
The hogdon Load Data for the 155 Sierra palma is 2.775", however I do know that the scenar is longer. Thus me asking. I'll work on some chrono info.
I'd be testing them at 2.860" OAL (.020" off). If you need to use a different magazine, I'd use the M+ from a 6.5 Creedmoor. That is what I'm doing with my 308w. Loading some as long as 2.920" OAL and working well. I do the same with my 7mm-08.
