I have a 243 built on a long action in a boyds varmint thumbhole stock that makes what I would call a humming sound after I shoot it. I gave had two different barrels on it with the same sound after firing. I have even gone as far as putting pillars in the stock and completely bedded the action with no change. The accuracy is good so I havent spent too much time trying to chase it down because I dont want to hurt the group size.
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