My SP-01 will digest pretty much anything without a hiccup. Steel cased, aluminum cased, laquered, copper washed, shorter than spec, longer than spec, reduced loads below IPSC power factor, +P loads, etc. etc. I have other much pickier 9mm's (a Para 1911 in particular) but my Glock and SP-01 shoot anything that even looks like a 9mm round without issue.
I've heard of people saying faster powders reduce "snappyness" or that slower powders will do the same. Any pistol powder can be reduced to reduce the velocity and felt recoil. I've tried everything from Reddot and Titegroup to Longshot and Bluedot and can't notice a difference if the velocity and bullet are the same. Maybe there's some minuscule difference but none I can detect. Heavier bullets do noticeably reduce felt recoil for the same given power factor but that's I think more related to power factor being a momentum calculation and not an energy calculation. A heavier bullet with the same power factor will actually have less energy than a lighter bullet with the same power factor. Since recoil is directly proportional to the energy imparted in the bullet, less energy equals less recoil. There are other factors of course but I think this would be the largest one. So my guess would be these reduced recoil rounds are just firing with a reduced velocity. I'd be careful if using them for IPSC or another sport that uses power factor since the velocity produced from the same ammo can differ greatly between guns. The ammo that shoots 128PF in my Glock is 132PF in my SP-01 and is nearly 140PF in my 1911 (138? I forget specifically). If I loaded my ammo for 128PF in my 1911 it would likely be under the 125 minimum in the other two pistols. Different barrels and chambers.
I believe Wolf will do custom reduced load batches specifically for ISPC shooters but the only person I personally know who ordered such a batch had to order a 25k round minimum. Worth it if you're a high-volume shooter who doesn't want to reload your own.
