my Tikka started loosing accuracy at just over 600 rounds to just over +.5MOA, at 650 i had the barrel cropped 1 inch and recrowned, also increased the COAL and accuracy is back to under .5MOA
an old school gunsmith with a lot of experience in .243s & 22/250s told me years ago that its not only the throats of those hotrods that erode but also the muzzle, recrowning can help to bring back accuracy . . it was worth a try.
Bookmarks