A word from Peterson…
The parent case for the .375 CheyTac is the .408 CheyTac. The .375 seems to be more popular in US, and the .408 is more popular rest-of-world. The .408 was created as a military round, and many of the casings we make are sold to military units. For that reason, we adopted the metric designation. The metric equivalent for .375 is 9.5 x 77. The metric conversion for .408 is 10.36 x 77. As not everyone knows the calibre by its metric designation our headstamp normally includes both the imperial and metric designation.
As you may know, the larger the caliber the harder it is to make consistent, high-quality casings. The .408 CheyTac®, which we headstamp 10.36 x 77, was no exception. Our tooling development team spent 17 long months and over 1,000 man-hours, and produced 49 different iterations of dies and stems before landing on the best combination to make a casing we believe to be superior to the other casings commonly used in CheyTac chambered guns.
The goal we set for ourselves was to produce .408 CheyTacs (10.36 x 77) with hardness values throughout the head and sidewalls that would hold up after more firings than any of our competitors. Our ballistician has repeatedly gotten as many as 15 reloads from our CheyTac casings without sticking, neck splits or head separation. We believe these to be the most precise, consistent and robust CheyTac casings on the market.
Warning: Only use Peterson Cartridge Co. casings in firearms in good condition, designed, marked, and chambered for this cartridge. Do not use Peterson Cartridge Co casings for “fire forming” or any other purpose other than what they were designed and tested for. Peterson retains no responsibility for the enclosed casings if they are used outside of the manufacturer’s recommendations.