Brent,
I cut the case at the center on a lathe to insure the case was square. I use your same procedure to find the position of the chamber that you do, except I have a set of collars that I can slip on my cleaning rod and lock in place. I use the collars to check O.A.L of cartridges. I have a jag that is faced square, close the bolt on the half cartridge, slide the rod into the bore, lock the collar at the muzzle. When I remove the rod I can place the collar against the muzle (O.D. of the collar is big enough) and scribe a line on the barrel to locate the strain gauge. The barrel isn't tapered at this point, so I can get a very accurate measurement of the barrel O.D. On the .270WSM, I did read the instructions /ubbthreads/images/graemlins/grin.gif and place the gauge an extra .125" foward to the muzzle to get the gauge 3/8" away from the reciever ring. Haven't had the time to shoot it just yet, I'm getting ready for the benchrest season here.
Al
I cut the case at the center on a lathe to insure the case was square. I use your same procedure to find the position of the chamber that you do, except I have a set of collars that I can slip on my cleaning rod and lock in place. I use the collars to check O.A.L of cartridges. I have a jag that is faced square, close the bolt on the half cartridge, slide the rod into the bore, lock the collar at the muzzle. When I remove the rod I can place the collar against the muzle (O.D. of the collar is big enough) and scribe a line on the barrel to locate the strain gauge. The barrel isn't tapered at this point, so I can get a very accurate measurement of the barrel O.D. On the .270WSM, I did read the instructions /ubbthreads/images/graemlins/grin.gif and place the gauge an extra .125" foward to the muzzle to get the gauge 3/8" away from the reciever ring. Haven't had the time to shoot it just yet, I'm getting ready for the benchrest season here.
Al