I run a Sig Romeo 5 on my M10/45 and an Eotech 512 on my Max31. Both run fine. I've pushed the Max31 out to about 145 yards. Makes hits every time on steel. Can't hit shit at 180 yards with the 45 upper. It's minute of school bus out there. Minute ish of man around 75-100 yards.
The 124s may help with a slightly longer pressure curve. Worth a shot. I've never actually run 115s in most of the stuff I own.
Congrats on your M11 and I'm sorry for your loss.