I have M70s in 7mm RM and 338 WM. 7mm is 24", 338 is 26". 26" almost seems better balanced in sporter stock and quieter. Shorter is nicer to carry, but 2" of barrel doesn't seem to make that much difference. In the article I liked above it says that the rifle became noticeably louder at 23" Seemed to me that 25" was the sweet spot in the test, but I don't think I'd go through the trouble and expense for an inch or two.
