so here is what i have;

12.5" noveske double chrome carbine SBR barrel
AAC SCAR-SD can, the old original short one
shooting Xm193 ammo
carbine butter tube with H2
brand new zero fail BCG with o-ring under the extractor

first off, i'm a timing guy and like things to be set up properly, not just good'nuf.

i was getting 2 o'clock pattern with spent cases and it feels pretty frisky. i stuck the H3 in and all the sudden the pattern changes to 1 o'clock which was the opposite of my expectation and understanding.

is this indicate an weak ejector spring maybe?

Could be a weak ejector spring.

not following ya there...can you elaborate?

You should also see gold lines/marks on the brass deflector if the cases are striking it first and getting thrown forward.