This was a coarse test to confirm a well-known load of 44.0 gr. Cases were primed with Federal Gold Medal Match Large Rifle primers. Overall cartridge length was 2.825″, with a cartridge base to ogive length of 3.200″ (with my comparator). I started the OCW at 43.0 gr and topped out at 44.8 gr. This was done because I had previous experience with Varget and the 168 AMAX bullets. Due to time constraints it was also performed over two shooting sessions. The first OCW was truncated on the high and low charge ends. Hopefully the statistical analysis of the system will help me identify correctable problems within the subsystems. The Shooting System in this case consists of the firearm, the ammo, and me the shooter. The result of my testing defines the rifle precision of the Shooting system. This will be illustrated below in the testing write up. Instead, I use the Mean Radius and Circular Error Probable as my defining metrics. The Extreme Spread (group size) of a 3 shot group is statistically almost meaningless and I never use it to determine the quality of a load. On my initial OCW tests I usually shoot 3 shot groups and then move to 5 shot groups in the tuning phases. I shoot all of my testing over a chronograph and save all targets, both good and bad. Recording as much data as possible is core to the statistical analysis of a rifle precision test. I do not have easy access to distances greater than 300 yds. Follow this up with tuning sessions at 100 yds. to establish charge weights that show potential. Perform Optimal Charge Weight (OCW) testing at 100 yds. The approach with a custom firearm with an inherently higher level of accuracy and rifle precision may be completely different. I have chosen what works best for me, under my constraints and with a factory rifle. Debating the best method is beyond the scope of this article. Load testing for rifles is a subject that has as many flavors as Baskin Robbins. I anneal after each firing cycle to maintain consistent neck tension.įor the data outlined in this article, I tested with Hogdon Varget powder and primed all cases with Federal Gold Medal Large Rifle Match primers. 002″ followed by neck sizing again with a collet die.
On subsequent firings, my steps are – full length sizing with a shoulder bump of. The case necks are deburred and chamfered. My first full case prep consists of full length sizing, swaging out the crimp, uniform the primer pockets, deburr flash holes and trimming all cases to 2.005″. Specifically, military primers are crimped in place and swaging out or cutting out the crimp is necessary to allow seating of fresh primers. Although some believe that the quality and consistency of this brass is not adequate, I have found it to be reliable, accurate, and durable.Ĭase preparation is important and there are a few steps that are specific to military brass not required of commercial brass. 308 Winchester is LC, once-fired military brass. I have found it to be a consistent choice for my Remington 700P. The testing documented below is specifically for the 168 gr Hornady AMAX. Bullets heavier than 180 gr are quite long and can lead to stability problems and a tighter twist rate is preferable. My rifle is a 1 in 12 twist, therefore I have limited my maximum bullet weight to 178 gr. The bullets range from 110 gr Varmint bullets to heavy bullets exceeding 200 gr. However there is an expansive selection of bullets for the. I am a hand loader and rarely, if ever shoot factory ammo. Ammo for my Remington 700P rifle precision testing An EGW picatinny 0 MOA rail topped with a Vortex Viper PST 6-24 X 50 mounted in Warne 30 mm steel rings completes the package. The original trigger on the rifle was not to my liking therefore I have replaced it with a Timney 510 adjusted to a crisp pull weight of 2 ? lbs. In addition the stock features a full length aluminum bedding block. The Model 700P is fitted with a 26″ heavy barrel and mounted in an H-S Precision composite stock. The firearm being evaluated is a factory Remington 700P, chambered in.