Throwing flyers out the bottom of the group

[NuJudge]

I have an Eddystone M1917 that I had Chuck in Denver rebarrel with a barrel I got from CMP. The first two or three shots from a cold barrel will group really well, then it will start dropping all shots out the bottom of the group. The flyers will be three, four, even five inches lower than the first couple at 200 yards using Federal Garand match ammo.

The stock is original. Grip screws are tight. There is some contact with the stock, but I am not noticing any strong pressure from the stock or the hand guards.

Does anyone have any suggestions as to what I should modify first?

[Pentz]

If it does this every time it has to be wood contact upon heating up. Try a slight pad at the fore end under the barrel. Otherwise you will have to use a lipstick or similar to chase down the contact issues along the barrel channel.

[kcw]

I have an Interarms Mark (30.06) and a friend as a Weatherby, (300 mag). Both of these hunting rifles have free floated barrels. Each will throw the 1st two or three shots in a nice group at 200yds. However when enough time has passed that barrels have heated through (usually within a minute of taking three quick shots), each will suddenly group to a point 5 or 6 inches from the original POI. As long as the barrels remain hot the secondary POI will be maintained.
My understanding is that this situation as to do with the orientation of the steel "grains" within the barrel. When the steel reaches a certain temp the barrel effectively "pops", and points in a another "direction"! When it cools, it pops back. This situation is totally repeatable.
Such barrels are generally considered to be defective and are commonly replaced. In our cases however we decided that we can live with it for hunting purposes.as we seldom engage in protracted combat situations while hunting. Three shots being fired within short order is rare and we've learned to leave the bolts open for a few minutes to cool the barrels down s so as to avoid the problem. This is especially true for the 300.
I don't know if you have an issue with the internal structure of your barrel, but I though that I'd run our situation by you for reference purposes..