[Unclenick]

Thanks for putting that up. It's interesting because of the slide locking effect. I suspect you are correct about the inertial mechanism in the case of the hotter load locking the slide back. In the case of the slide failing to lock back, do those loads feel noticeably lighter? I can tune targets loads in a model 1911 until the slide is no longer slamming all the way into the frame via the recoil spring guide, but still goes back far enough to eject and feed properly. I can tell when it happens because recoil abruptly becomes mushy when the charge weight comes down to that level. If you are experiencing something like that softened recoil, you may simply not have the slide going back far enough for the slide stop to engage. I don't have a copy of this particular gun, so I can't look to see if that's possible.

The blame put on magazines for the failure of the slide to lock back would be the magazine spring not having enough extra force to push the slide stop up quickly enough to engage before the slide is on its way back into battery. It could have that problem and still feed rounds. You can test for this by pulling one of your mags apart and stretching the spring out a little bit—maybe the length of one turn of the coil—and putting it back and seeing if that fixes it. If so, the fix may not last, as the need to do it in the first place is a sign the spring has taken a set or is fatigued, and will wind up back where it was eventually. If this fixes it on your first few tries, you want to consider getting new mag springs, and ones with extra power if they are available.

Your observation about recoil and noise is correct. H110 burns more slowly and its charge weight for the same velocity is heavier. Your 2400 load is producing higher peak pressure, while the H110 is getting more of its bullet acceleration from holding pressure up higher in the barrel after its lower peak has passed. This means that when the bullet clears the muzzle, you have more powder mass to blow out of the barrel and it blows out at higher pressure, and the combination makes a bigger rocket impluse, pushing the gun back harder. This is something that is generally true about using slower versus faster powders in all guns. Relieving the barrel of the rocket effect pressure is why muzzle brakes work, leaving only recoil due to pushing the bullet out for you to feel. In some overbore rifles, rocket effect can be half the total recoil.

I added the forum load warning because your H110 loads are below Hodgdon's minimum of 23 grains and Hodgdon has long had a warning not to reduce H110 loads that much because of problems with squibbing out and leaving a bullet stuck in the barrel for the next round to fire into and cause damage. My personal assessment is that this is mainly a revolver problem, abetted by the barrel/cylinder gap gas leak, but someone may try to fire your loads in a revolver, so the warning is still appropriate.