I took the BF rifle out last week at 200 and the results were very disappointing! I had a very bad case of vertical stringing! Rather than post it and let speculation run rampant, I decided to solve the problem first, then post it. Here's what I was seeing last week...
This led me to investigate possible issues. I looked over the stock with a very critical eye. I found that the heel was floating over the stock by about 0.012"! I checked the fit of the receiver and the legs as well as the front of the receiver was in full contact. No amount of hammering the receiver with a mallet was going to fix this...
I also noticed that my scope had "skid marks" from where the scope had walked back about 2mm over the last few months of firing. I reseated the scope and hit the range again to see if the scope or the floating heel was the culprit. The vertical stringing was still there. I ended up shimming the heel with muffler heat barrier tape and trimming them to fit. Each layer was 0.003" thick so I laid four layers down.
That 5 minutes of shimming tightened the groups right up and I ended up shooting 7 consecutive 5-shot groups at 200 yards with a low of 1.290" and a high of 2.700" with an average group size of 1.988" at 200 which would be a 100yd average of 0.994".
Life is good! And I get a Leupold scope later this week.
To M14.CA's credit, it is nearly impossible to design a stock that will fit all commercial receivers. I don't know if the issue is my receiver or the stock. If there's a gap, I have a fix and it's cheap and quick.