Winchester
The majority of Winchester Model 70 type actions will use the Standard .860 rear hole spacing including magnums, pre-64 standard calibers and WSM calibers. Express calibers such as 7mm STW, .300 H&H, .300 Weatherby, .375 H&H, .416 Remington or .458 Winchester will use the Express Caliber bases with the rear hole spacing .330. Pre-64 (rifles manufactured prior to 1964) chambered in .300 H&H, .300 Weatherby, .375 H&H, .416 Remington or .458 Winchester will use the Pre-64 Express .435 rear hole spacing.