Gotcha, Badger -- yes, I missed your question altogether.
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<br>"It is a Model 7 Youth in .243Win that only starts to group decently with a warm load. Littlebit & I were talking about it and theorized that this rifle may have a bedding problem. It takes 42 grns of IMR 4350 behind a 100grn Partition to make it MOA or better. Interestingly, the POI shifts drastically with reduced ... loads ... and grouping opens to more than 4". The POI is approximately 4-6" lower at 100 yds with a starting load (about 37.5grns IMR 4350) Your thoughts on this?"
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<br>I think you may be right -- that you have a bedding problem. That much variation in POI can't be blamed on the difference in muzzle velocity, and the variation of group size strongly suggests bad variation in the barrel's vibration pattern.
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<br>You may also have a related problem -- the torque on the action screws may be partly to blame. They may be too loose, too tight, or too unevenly tight.
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<br>If it were my rifle, I'd glass-bed it, probably with pillars to boot, and make sure that the fore-end didn't touch the barrel anywhere. Then I'd invest in a good torque wrench (I bet you know exactly where you can lay your hands on one!) and mess around with the torque on the action screws.
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<br>For a bedding compound, a number of the bench-rest gang recommend Charley Robertson's Pro-Bed 2000 (
http://www.scorehi.com/scorehi/home.htm). I bought some but haven't used it yet, so I don't know how much better it may be than the good ol' Acraglas and Acraglas gel I used so much of in years gone by.
