I just ran off 500 rds of 180 gr over 36.5 and 38.0 grs of 3031. I loaded the first 200 in Hornady cases at 38 grs and last 300 batch at 36.5... Why?? The brass I got from Grafs didn't have the same case capacity as the Hornady, it holds 3.5 grains less and was the difference between a compressed load and the std load I use. I also found a couple that didn't have a flash hole. No biggy,,, that's why we pay attention.
Both loads shoot to POA and velocity is very close to the same in the Remington M81. So, be aware the Graf head stamp brass is a bit less in case capacity. Its a real kick to run off 15 rounds rapid fire with the POE magazine.