I am getting a new barrel on my 7mm Rem Mag and am not sure what length to get. I used to use it fo an eastern whitetail rifle, but now want to use for long distance muley and antlope, hence the rebarrel. If I was not going to change my load , I would keep with a 24", however, I have aquired a boatload of Hogdon retumbo that I want to start load developement with this powder. I have not settled on bullet weight yet, will most likely be 140 to 168 area. My concern and question is , when loading the lighter bullets and approaching max load, will I be throwing unburnt powder on the ground with a 24 inch barrel? Retumbo is a pretty slow burner. Any thoughts?