case neck growth

[Barlow]

Yesterday I annealed 25 (about) 6 Dasher cases. They are Lapua and have been fired approx. 6-8 times. I cleaned them up, resized them in my Forster neck honed die, trimmed and primed them. I noticed a couple cases seem snug on my Forster mandrel when I trimmed them. I then measured the ID of the case necks, they are supposed to be .240. 12 of them miced .238- .239, mostly .238. Measured with a Mitituyo caliper. I spun them a little with the ID prongs in the case. I know it's not the best way but it's what I have. I set those cases aside and went for supper. This morning I measured them again, they miced .240 or very close to it. The cases that were at .240 stayed the same, what gives? Barlow

 

[Barlow]

Seems like the three most common word in the English language are; experts were surprised. Barlowe

 

[liseo]

Some years ago I annealed some 308 cases. They do the same.