I believe Steve at Hammer ha run into this before. I think I remember some one having issues with stability using one of their bullets. When they checked the twist it was not as advertised. I wonder how many of the various bullet failures we hear about are caused by people using bullets that are unstable because the twist in their barrel is not as advertised.Things aren't always as they appear. I have a Savage 112 BVSS 9 twist. I have carefully checked the twist using the method above and it measures out to be an 8.5 twist. Repeated tests all show the barrel to be an actual 8.5 twist. It does shoot 77gr bullets quite well. Just for laughs I'm going to try some 80gr ELD-M bullets that I've got sitting around.
I've heard of other barrels that were way off from the twist stated by the manufacturer.