This is an interesting thought exercise.
How would the dimensions of the RLL/SP1 carrier vs GI sear/M16 carrier come into play? Or maybe it’s the method of instigating automatic fire that makes the difference?
The SP1 carrier is shorter and shelf is more rearward, but the carrier is slamming into home position when the disconnector is tripped. Maybe that’s dimensionally no different than an M16 carrier traveling forward to trip a GI sear, but it seems like a slightly faster window.
The only other thought I have is the RLL is working on the disconnector to move it back off the hammer and release could be a little faster than the GI sear. The GI sear moves forward, releases the hammer (possibly with a slight dip downward on the hammer before having inertia to release and let the hammer fly), and the hammer flys forward.
I know this entire process is milliseconds in length, so we’re talking minuscule differences. For reference, Surefire states their OBC increases cycle times from 28 milliseconds to 38 milliseconds. So if the RLL cycles in 26 milliseconds vs 28 on a GI sear, that could be just enough to change the ROF noted above.
Honestly, without an SOT having a cutaway post sample and a high speed camera, I am unsure how you’d “prove” one method over another.
Edited for fat finger typos.