I agree with Captchee; it's not all that unusual to find a warped stock, in the barrel channel area. Typically caused by the drying of the wood that was not allowed to season long enough. Mass producers always kiln dry their blanks which dry's the blank but does nothing to relieve stress in the fibers. That's where the warpage comes from. I almost never start a build with a precarve that is less than 6-8 months in my possession. AND I always install the barrel upon receiving the kit, just to prevent this warpage. The wood fibers will dry and conform to the barrel just fine. Also, nearly all warpage will be side to side, and shrinkage will be up and down. To avoid the dreaded, "proud tang", please allow the stock to season completely, and a full year is not to long, depending on where you live.