I worked a load for a buddy's rifle with used remington brass. The load consists of 73grs of retumbo with a winchester magnum primer and 162gr A-Max bullet. About 1 in 5 rounds it is hard to open the bolt. The max that i have found for this load is 73.5. Other than the occasional sticky bolt there is no signs of pressure. I have been loading for about 5 years and never had this problem. Any info would be greatly appreciated.