guys, i think there's something wrong with this gun'.
this should mean one hole groups at 25 yards.
i fixed up some shade at 17 yards today.
i shot 3'' groups.
something is very wrong but dry firing says it can't be.
In reading over your procedures trying for good accuracy from what is essential a "target / combat" revolver; I have reached the same conclusion you have, about; "something wrong is going on here !".
In spite of your obvious dislike of standard sights, I think you have put in enough effort with the mdl. 15, to be consistent in smaller than 17 yd. - 3 inch groups.
While everybody remotely familiar with the model 15 knows, and has stated here several times, what a fine target shooter it is, not one of us would be happy with 3 inch groups at that yardage with the amount of practice you have put in.
If I recall your previous post on firearm matters, you have a fair number of varied shooters with which you have mastered their intended purpose.
Yet, in spite of your obvious diligence to reach accuracy potential with your first S&W revolver, something seems amiss.
You have stated more than once the lack of a go-to source for a shooting companion, but I would hope there was a way to get your 15 in the hands of a proven target shooter of revolvers, (although from my recollections a person shooting accurately with one type of firearm is likely good with any and all).
Rimfire, centerfire, semi-auto, revolver, or rifle. Some better with one type or another, but still......
The opposite of letting someone else shoot your gun would be letting you try another's .38 revolver, which of course is rudimentary "trouble-shooting" of a problem . "If it ain't the gun; it must be me" type of decision.
Good luck with it, you certainly seem committed enough to "get it right" !