FYI, for those needing commercial gas checks,
FS Reloading has a number of Hornady crimp-on gas checks available in 6mm, 6.5 mm, 270, 338, 375, 416, and 475 at reasonable prices. I have ordered from them in the recent past with good customer service and order delivery.
See: https://fsreloading.com/Special-Offe...ding_Supplies/