How about checking for consistent muzzle diameter (..er, dimension) with other short octagon barrels? We discovered that early model 99C's with either 22" or 24" barrel both had the same exact muzzle dimension (i.e. the 22" was not just cutoff from a 24", they were turned with different tapers), and we confirmed that with five different model 99C.
My 26" octagon is .945" at the receiver to .6465" at the muzzle (.6965" at 20" from bolt face)
I have a 20" and a 24" octagon barrel, both 303's, and they both measure exactly .691" at the muzzle.
