Sounds like you either ain't swabbin-cleanin' the ML correctly while at the range - or you are shooting too rapidly -- or you need a wad between the powder and sabot -- or T/C shipped you the wrong front sight & you need a shorter one.
Start-off by making sure you have a bore brush, 3" patches and basic windex or alcohol for the range - then afterwards a gun solvent that controls plastic, copper and lead. Swab the bore with windex or alcohol after every 2nd shot using a bore brush-only. The jag should only be used when loadinfg/seating the bullet. That avoids problems down the road. Using a bore brush keeps the rifling unclogged while sighting-in -- allowing better spin/engagement contact.
Alsao, there's not alot of difference between 90 and 105 grains at 50 yards. You will see a biogger shot group differential at 100 yards.... but maybe only an inch or two.
There's also a chance your gun doesn't care for the Super Glides with out a wonderwad. Try a different style of T/C-packaged bullets - perhaps in 300 grain this time. If your sights are "maxed-out" in adjustment, call T/C by phone-only & they will ship you another front sight that's different.
See if all this solves your problem. Here is a good, basic solvent that keeps everything under control.
Birchwood-Casey 2 in 1 Bore Scrubber