Jeep,Have you checked all of the Action screws,Rings,bases,etc., to make sure everything is tight and torqued to the correct specs.
If it was shooting great before,and not now,I doubt it is a barrel or chamber problem.
I have a Savage 10FCP and 12 FLV in 308 Winchester,both have always shot excellent,but I haven't ever shot any bullet weights under 165gr.Plus,I only handload for all of my guns.
It may be that your barrel doesn't care for the lighter weight bullets,but it should still put them on target if everything is tight on the rifle.Both of mine love 168gr-210gr match bullets,and Nosler 168gr Ballistic Silvertips for hunting chores.
Texas State Rifle Association
North American Hunting Club