I've got a lightweight 9.3x62 that bucks a bit, and I'm thinking of having it magnaported to help control muzzle rise. My only worry is that the 9.3, because of its relatively high expansion ratio might not benefit from the magnaporting in the way other, higher pressure / lower expansion ratio calibers (such as the 338 Winchester) do. Does anyone have experience with a magnaported 9.3x62? Or magnaported 35 Whelen or similar expansion ratio cartridge?

Oregon I would agree with your statements that you may not receive the most benifit from magnaporting a 9.3x62. However one thing you didn't mention was the shape of your stock. I would like to suggest that if you have a European style stock with a fair bit of drop at the heel that will contribute to muzzle rise and the cheekpiece of your stock tends to slap you in the face. This contributes to "felt" recoil. The 4 hole magnaport pattern would hold the muzzle down and reduce that slap to the cheek."Felt recoil would be reduced considerably. If you have a straighter stock with very little drop at the heel I think you would see less of a benefit. Also anything that helps keep your muzzle down will help you get back on target for a follow-up shot.