I agree re 'match ammo', too.  Especially if your rifle is of 'current manufacture', since consensus is that quality is falling in recent years.  If you have a quality replacement barrel I'd still try some CCI-SV if that will cycle the Ruger.  And 'match ammo' comes in many flavours, ie brands and grades within brands.  I wouldn't buy a brick of any w/o testing several of those various flavours.
As for the scope, get the best you can afford, within reason.  I have a $700 Athlon 8-34x56 FFP on a $400 Savage B22FV and getting sub-1/2" groups at 50-yds with SK-RM, an 'entry-level' match-practice grade.  I don't shoot matches since there are none within 100 miles of me.  And all NB ranges are closed anyway due to 'fire closures'.
PS - My CZ457 VMTR gets 0.3xx" with the same ammo, just a bit better.  Generally, semi-actions don't get 'super-accurate' results unless you invest a lot in the equipment.
JMO