The Mark V action remained relatively unchanged during the first five years of its production, until manufacturing moved from PFI in the United States to J. P. Sauer in Germany. The Sauer produced version differed from that manufactured in the United States, with the safety moved from the receiver to the bolt and the smooth surface of the safety found on the US made versions was replaced with a fluted surface. The first major change to the Mark V came in 1963 when Weatherby shortened and trimmed the design of the action around their 224 Weatherby Magnum varmint round, which had been designed in 1964. The bolt in the smaller Mark V action had six locking lugs, as opposed to the nine locking lugs found on the parent rifle chambered in the 378 Weatherby Magnum. Rifles chambered for the new 224 Weatherby Magnum cartridge were dubbed the "Varmintmaster." The Varmintmaster was later offered in a version chambered for the 22-250 Remington, making this the first non-Weatherby cartridge offered in the Mark V rifle. A version of the Mark V rifle equipped with a nine lug bolt and chambered in .30-06 was also made available in 1967. These two cartridges, the 30-06 and 22-250, remained the only two non-Weatherby chamberings offered in production Mark V rifles until the mid-1990s, although Weatherby would still build a custom Mark V to a customer's specifications in virtually any caliber. As all Mark V rifles made after 1967 that were chambered for non-Weatherby standard calibers (not magnum cartridges) were equipped with the six-lug version of the bolt, this makes versions with a nine-lug bolt chambered in 30-06 (whether made in Germany or Japan) somewhat rare.