No, didn’t know that.
My mistake.
I do apologize for my mis-information.
I don’t think you have anything to apologize for. I think it’s a good thing that there’s a little more info out there to let people know they’re not an instant felon if they have a semi auto bolt with a full lip. The obscure ATF ruling is just one little inch of victory towards firearm freedom, which is rare these days.
Pure speculation, but I think milling off the feed lip was just something IMI had to do to appease the government to import the guns, but doesn’t apply in any way after they are here or if they’re built here.
As far as dropping into a RR to convert to closed bolt, I’m thinking the blocking bar slot being cut out and the weight lost would have little impact on ROF. I think the crazy cyclic rate is drive by the dual springs and shorter travel distance.