Pressure Testing 6mm MAX
Energetic Materials Research and Testing Center
With months of planning, we were finally able to take the 6mm MaxTM for pressure testing at the Energetic Materials Research and Testing Center in Socorro, NM. Testing was held three full days from April 18th – 20th.
Below is an Excerpt from EMRTC’s Final Report:
BC Precision Ballistic (BCPB) desired to have Sporting Arms Ammunition Manufacturers Institute (SAAMI) specification testing performed with a range of bullet weights and propellant with the 6 mm MAXTM cartridge in order to establish SAAMI performance standards. Testing was performed on the EMRTC Ballistic Sciences Laboratory (BSL) in April 2022.
A SAAMI minimum specification 24” pressure and velocity test barrel was used fitted with a PCB conformal pressure transducer. PCB performed a gage/case calibration to determine gage output/slope and offset. The slope was .166 PC/psi and offset was 2,821 psi. The test barrel and transducer were mounted in a standard universal receiver. An Oehler system 85 was used for data acquisition. Oehler model 57 chronograph screens were used at 10 feet and 20 feet from the gun muzzle to provide the SAAMI specified velocity at 15 feet from the muzzle. 10 rounds were fired, cleaning every 2 rounds, to break in the barrel. Rounds previously loaded by BCPB were used for break in. After break in the same BCPB rounds were fired to establish a baseline reference ammunition performance with the new barrel This ammunition was used as reference ammunition and 5 shot groups were fired after cleaning the barrel, approximately every 150 test rounds on the barrel, to provide barrel corrections throughout the testing. With 190 rounds on the barrel, approximately half way through the test, a correction was done on the barrel that resulted in corrections of +7 fps and +1,900 psi.
A maximum Average Pressure of 55,000 psi was used for the tests with no bullet/powder load combination performance being established over a pressure of 53,500 psi in order to allow for production component variations.
Cartridge cases were supplied by BCPB primer with CCI #41 primers. Various bullets weights and types from various manufacturers were tested with a range of propellants. Bullet weights tested were 55, 58, 65, 70, 75, 77, 80, 87, 90, 95 and 100 grains. Propellants tested were IMR 4198, H322, RL 10X, VN 133, H335, IMR 8208 XBR, H4895, VN 135, RL-15, BLC2, WC748 and CFE 223.