Hello Psyfly
To answer the basic question you asked: Yes, you will get better if you practise properly.
A three inch pistol is not normally a target grade gun. But the accuracy potential between a three inch gun and a five inch gun are not as great as commonly believed. Much of this is a matter of reasonable expectations. For the record, a three inch pistol that will not reliably hit a 9 inch disk at 25 yards and probably at 50 yards is defective (excluding shooter inability.)
If I may, a couple of comments and observations:
The essence and primary skill in delivering any shot on any target - bullseye, ground squirrel, moose or armed attacker - is sight picture and trigger control. Obviously, the margin of error is greater when the target is large and up close, but there are limits of error in all circumstances. As you so correctly said
... I am not comfortable ... in real-time SD if I can't hit anything under ideal conditions.
You got that right, pard. I've read too many reports of gunfights at less than powderburn range with less than a one-in-three hit ratio.
I've done all kinds of shooting in my life, pretty much everything from bullseye to IPSC to silouette. I've carried a gun for a living for many years now. I've never shot anyone, but I've taken several guns and knives away from people.
Knowing you can make the hit under any circumstance is a big advantage. Bad guys pick up on that.
By the way, I'm now 58 years old. I'm a bit overweight and my knees, while still servicable, are going out on me. I like 'action shooting', but I can't do the running, jumping and sliding under limbo sticks so beloved of that 'sport'. So I do understand your position regarding violent excercise. I still shoot bullseye, and I shoot a monthly International Centerfire match; part of that match demands a fairly precise shot fired within three seconds (to obrain sight picture and shoot) - thirty times. It's good practise for this sort of thing.
And the idea of
...draw your weapon and shoot. Miss or not, just shoot.
is great. Unless you have to explain where your missed rounds went. Like in a self-defense shooting.
Lord protect us all from 'supressive fire'.