38 special and 357 mag groups in a Blackhawk

[tazman]

As mentioned in another thread, I recently put a reflex sight on my Ruger Blackhawk with 6.5 inch barrel. One of the cast loads I tested provided excellent results.
Since one of the indoor ranges I frequent doesn't allow magnum loads, I wanted to develop a load in 38 special that shot near the same impact point as the magnum load did.
I really wasn't expecting much in the way of getting close to the same point of impact without some serious work but apparently I got lucky.
The magnum load that shot so well was 14.2 grains of IMR 4227 under a Lyman 358429 boolit. It is probably running around 1200 fps. The gun is sighted at 25 yards(the length of the indoor range).
The 38 special load that ended up working was 5.0 grains of CFE pistol under the same 358429 boolit. It should run around 900 fps.
The group for the 38 special load was only slightly larger than the magnum load and impacted approximately 1 inch to the left at 25 yards. Easy enough to just aim off slightly.
Other boolit weights and designs didn't shoot anywhere near the original point of impact. For instance the 158 grain boolits shot several inches lower and to the right. The light wadcutter loads I tried shot very accurately but almost a foot low.
I certainly didn't expect the same boolit to shoot to point of impact with a much lighter charge.
I guess my question is, is this typical of this type of gun/ammo combination or is this just one of those "the gun makes it's own rules" things and I got lucky?

[Petrol & Powder]

I've always found that bullet weight has a bigger influence on P.O.I. than charge weight.
I did have one model 64 that gave me fits until I upped the charge weight to near maximum but it was the exception.

Now, if you get the velocity real low, things do change dramatically.

[shoot-n-lead]

I've always found that bullet weight has a bigger influence on P.O.I. than charge weight.
I did have one model 64 that gave me fits until I upped the charge weight to near maximum but it was the exception.

Now, if you get the velocity real low, things do change dramatically.

X 2

Bullet weight has always driven POI in my guns...with a very few exceptions. I am shooting one now that seems to be an exception to that...it seams to prefer one style bullet, in medium or heavier weights...very near same POI.

[Scharfschuetze]

Lucky you Taz!

Usually it takes a heavier boolit when fired at lower velocity to shoot to the same POI as higher velocity round.

It's all about barrel time and muzzle flip while the boolit is traveling down the barrel.

[tazman]

That is what I was thinking and why I asked the question.
Apparently this gun makes it's own rules.