Joel, I have built (but do not recommend it) a 338 Improved Lapua on a long Savage Single shot, think it was a 112VS. No magazine cutout, and a long bolt throw, so it handled the Rigby sized Lapua case fine. Check your magazine length, you want at least 3-1/2 inches for the Howell so you can seat those bullets out where they belong, although it will function at 3.34" which is the "Standard '06" length, but at a little less powder capacity. The other thing to check is if the 404 Jeffery cases (from which the Howell is formed) at the larger diameter will stack in the magazine OK and offer proper feeding. If I had a Savage in the shop I would check it for you, but I don't have one now.