Truly 6" at 25 yd ?
Thats too much for barrel flip. Something else must be loose.
My 7mm08 had 10cm change at 100m with suppressor on. Then it went crazy 20 .. 30cm out worse with supp off than on ...
Turned out a scope base screw had come loose and the suppressor was affecting how much unpredictable movement occurred in the mounting. Tightened that one screw and it went back to behaving itself.
Is your gun shooting well with the suppressor off ?
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