If you have a piece of 260 AI brass that was shot in the gun but has not been resized, chamber it, snug up the barrel against the shoulder, lock her down where the bolt is a little snug to close. You have have now tightened up your headspace - .0005. or less than it was before you took the barrel off. Worst case scenario you bump the shoulder back .001 on resizing to loosen the bolt. Yeah all the smiths and book worms say no but if you know what your doing as a reloader this aint no step.