I have a question for the revolver guru’s. How much thread choke does it take to affect accuracy?

Yesterday I was bumming around the gun shops and found a used stainless Ruger Bisley .45 Colt with a 5.5” barrel. It looked lonely and in need of a good home so I bought it.
After a good scrubbing, it was filthy, I slugged the barrel and cylinder throats. The cylinder throats measured .4511 to .4512, the groove diameter is .4510 with the thread choke measuring .4507
I took it shooting today with some ammo that I had loaded for my Ruger Flat Top. The first load I tried was 8.0 grains of Power Pistol, a Lee 255 grain flat point with a BHN 15 and a CCI 300. I set the target at 25 yds to do a rough sight-in. The first 5 shots landed in .4” and made one ragged hole, The next 5 shots landed in 1.25”. I think this gun is a keeper and I’m sure glad someone decided to trade it in.
Before I shot the revolver I was thinking of fire lapping it to remove the thread choke, after shooting it I think I’ll leave it the way it is.
Getting back to my original question. My .45 Flat Top had .0005 thread choke and shot 2.5” to 3” at 25 yds, after fire lapping it shoots 1.5” to 2” groups, not great but better. How do you decide when to fire lap?
Greg

I would not do it on a piece that shoots 1 1/4"groups.

If it shoots and doesn't effect function who cares.

I've fire lapped two revolvers, the first one resulted in a noticeable improvement, the second one didn't change at all.
I guess I was wondering at what point will you see an improvement.

I've yet to have a choked Ruger shoot that well. My 357 blackhawk shot 3-5" groups at 25 yds when choked, after boring a taylor throat into the barrel, the worst groups it shot have been 2" at 25 yds.

My super blackhawk wasn't as bad, but the taylor throat tightened it's groups up as well.