Dave,
Thanks for the tip. The barrel is not a "high end" barrel, but an Adams and Bennett from Midway. I have some 5/8" 3 shot groups (at 75 yards, my range setup). So It can shoot. They are always the first rounds. The stringing is happening as it heats up and is not random. Again, it has been real hot here.
I built the rifle myself. I am pretty proud of my "float and bed" job. But this may be how I learn even more. I will try the index card trick, it is a good idea.
Jerry
PS. I had a factory Rem 700 BDL .270 that stringed until I had a gunsmith bed the action and float the barrel. Worked like a charm. So I thought I would do the same.