ORIGINAL: Soilarch
I see that remington's factory load is 200 fps slower than a 7mm-08. Is this because of chamber pressure worries in older guns or does the 308 offer more powder space?
It is because of worries about old, weak 7X57mm rifles, especially the ancient Remington Rolling Blocks. In a modern rifle like a Ruger M77 or No. 1, the 7X57mm can be safely loaded to exceed the 7mm/'08 (but not by much), and tread right on the heels of the .280 Remington. For example, a 22" barreled Ruger No. 1A 7X57 with the long throat can be
SAFELY loaded to approach 3000 FPS with 140-grain bullets, and 2700 FPS with 175-grain bullets. The same relationship exists between ALL cartridges of the same calibers that are respectively based on the 51mm ".308" case vs the 57mm "Mauser-type" case, eg., .243 Win vs 6mm Rem., etc.