Sam,

I had noticed that as the gun got hot, the shots from my old Merkel SXS 9,3x74r would cross over each other, and my new old Merkel o/u in 9,3x74r crosses up and down.

The SXS showed a bit of elevation change, also, while the o/u shows only minor windeage changes.

I was sighting in a new scope on my pre war Sauer cape gun in 12 & 8x57jrs a week ago and noticed that it moved almost a foot to the left as it got very warm...rifle barrel on right, of course.

I always cool combo guns and DRs between series of a shot out each barrel and was wondering whether this is prudent in the heavy calibers. A 9,3x74r is the biggest bore I have any experience with in DRs, and they can be quite lightly made, possibly lending themselves to more movement as they heat up...

Dugaboy...what say you? Do you let the bigger DRs cool when sighting in or regulating?