Just an update. At the clinic, I shimmed my rifle - so now it was time to test it.
I used Remy bulk and Winchester (both 150 grain pills) ammo and benchrest at 100 yards. Now my eyeballs are not what they used to be so the target through the sights was a little fuzzy, but I tried my best to aim as consistently as possible.
Lo and behold, she was shooting approximately 1.00" MOA (excluding the odd flyer) with the Remy ammo and about the same with the Winchester. I was impressed because the addition of the shim really improved the accuracy of the rifle. I then went to the 200 yard range and shot at a 10" gong using a hunting stance (sitting - supported with sling, no benchrest). 15 out of 15.
While they were not tight little groups, the bottom line is that for my ability, my M14 shoots very well indeed.
Now have to find some time to shoot my reloads and see how they shoot.
Without attending the clinic, I would not have been able to do this as the rifle was shooting between 1.5" (best grouping on a calm day, reloads) to 2" (average).
Thanks again Hungry!