Originally Posted by CB11WYO
MMERSS... How major is the temp sensitivity? any data?
Using RL-22 out of a RUM I was seeing about 5 ft/s difference for a 10 degree temperature change.
With that said, I haven't shot my 7mm in hotter temps to verify the velocity change or any internal ballistics change requiring corrections due to the different pressures. I load developed around 40 degrees, roughly the same average temperature during hunting season. The 7mm hasn't been shot above 60 nor below 30 so I haven't taken the time yet to verify and establish temperature regression on this RL-22 load.
If you are considering a more temperature sensitive powder such as RL, try developing your loads in the coolest part of the day such as before sunrise to mimic the cooler temperatures encountered during big game hunting season.
So far, I have had great success with the groups and velocity variations using RL-22 in my 7 Mag. I would bet no matter how much I try, Hodgdon Extreme powders in this case would be tough to equal or exceed my current results. I'm not willing to try to fix what isn't broken just for the sake of temperature regression in this case. If it appears I will be using the rifle in more extreme circumstances, then yes I will conduct regression testing and apply the velocities to each temperature band.