Originally Posted by Coach Hunt
My 7WSM has a #4 barrel; however, it is about ready to go "the way of all the earth" as my Pappy said. I'm exploring a #5... no fluting... and 28 to 30 inches long. I'll be watching this thread carefully!!!
Your problem is that lack of barrel ridgity, and going to a heavier barrel and longer will not help the issue, but probably make it worse. Lilja did some testing a few years back on #7 contours, and found that a 21" barrel in #7 was was 2.75 times stiffer than the same contoured barrel 26" long. That means better harmonics and better groups. Now a 21" barrel is a little on the short side for sure, but the reloading manuals use a 24" barrel. I think a #5, 23" long will still show 3000fps with 154 grain bullets. Yet will probably be twice as stiff as the same thing 26" long in a #4 contour. Fluting will not add any value to ridgity to speak, but will cool faster (not a serious issue here).
I think that since you are going to rebarrel any way, it might be a good experiment to cut the barrel back to 23" to see if it shoots better groups (you may need to change powders). If it does you will know that the next heavier contour barrel will only help. You'll also find that the shorter barrels have better balance and tend to point better in a hunting application.