My worst was a early 70s Ruger M-77 in 7x57.
I spent a whole summer spraying bullets at a targets.
Finally found it would shoot v-e-r-y long Sierra's into 2"s on a wonderfully good (or perhaps lucky) day
Sent it to local gunsmith that shoved a 280 reamer into the chamber & turned it back one thread.
PRESTO.
It'll shoot 1 to 1 1/2" all day with most loads & I have lots of targets with groups in the 3/4" range.
It's now my "go to" gun & has accounted for lots of moose, deer & a few wolves
