Agree with by mike m's review (aug 6, 2021) - killer innovations barrel and axg - good, but 1 caveat - DPM SIG Sauer P320 Compact Carry 3.9in Barrel Mechanical Recoil Reduction System

Similar to Mike M, I've had issues with the KI barrel - but found that it might be in the milling of the barrel and not necessarily the recoil spring. With regard to the base of the guide rod catching somewhere on either the slide or frame components, I've found that one has to properly set the "free" recoil spring in such a way (trial and error) that when the assembly is compressed, there's less pressure on the guide rod end to twist against the base of the guide rod "block" at the bottom of the barrel (the "catch" that holds the guide rod end in place upon reassembly). This is the poor man's approach to addressing the problem - though no guarantees that this won't cause the same problems eventually after several hundred rounds.

On AXGs, the guide rod end is round. I suspect that the older elongated circle (basically a square with half-circles on the end, like on an M17/M18) or oblong (like on an an X-Carry or X-Comp) OEM guide rod, just doesn't work flawlessly with the new design of the AXG slides. Haven't figured it out - but this has caused locking-open issues for me as well. To the point that I accidentally shot my slide forward and broke my optic, trying to dislodge the slide from the open position. (yes, painful)

I've since taken the guide rod to the armorer to have it milled - no issues since. (knock on wood)

As for the reduction in felt recoil... well, it's hard to quantify since the gun has this recoil spring assembly, a comp, and has weight added all over, and on a metal frame nonetheless. I'd say it helps. Using the medium spring, no FTEs, even with an AC comp. Just that slide-locking issue :/