LA mag cut out location

I know the long action screw spacing hasn't changed, unlike the short action, but I have found out there are at least 2 different magazine cut out locations. Although, the difference is only a couple of millimetres when using the wrong DBM or chassis and a AI style LA mag, the mag will not seat fully or feed rounds.

I think the main difference is between the BA 300/338 large shank action and the normal long action. Can anybody confirm this?

I've bought one chassis and found out my three long action rifles have this problem and after emailing another chassis company they measured the mag well and seems its for the BA cut out as well. My fix is to mill the feed ramp of the action to make it match up, which I'm not all that keen on doing. To my knowledge CDI Precision and XLR offer the two different LA cut outs.

I was also wondering if all newer long actions are all the same cut out now.

It would be nice to know for sure, so when I get bored and go emailing the different chassis makers I can mention this!

Any ideas!