Norseman: at 25-50' she hits slightly low?? How low is that? If you take a 6 O'Clock hold on a 4" bull at 25m your pistol should impact about 2" high for a dead-on impact at 50m. Yours are over a foot low at 25m.
You didn't say what 230 gn fmj ammo you were using - some is not loaded to mil-spec. I have noticed a difference with some different brands of ammo and finally settled on S&B ball as it is accurate and impacts properly with my mil-spec sights. Anyhow, a foot low is too much.
The 3 dot sights should be regulated to the same point of impact as the mil-spec sights and are pretty well standardized. I would think it might be something like your barrel link being too long - easy and inexpensive fix if you do your own tinkering. You can get a couple of different lengths and experiment. That shouldn't change your groups. HTH. Mikey.