Just acquired a second Ruger Flattop Bisley in 44spl with a 4 5/8" barrel so I figured I'd shoot it side by side with my 5 1/2" model to see if I noticed any practical differences.
I shot both revolvers at 25 yards with a load consisting of a 240gr Oregon Trail LSWC over 16gr of 2400 powder and a large pistol primer.
After shooting 30 rounds through each, here's my conclusions:
1. Accuracy: The extra barrel length of the 5 1/2" model, though it doesn't look like much when the guns are side by side, does make a difference in sight picture. The front sights are equal in width, and with the 4 5/8" model the front sight fills the rear sight notch completely with a small hair of overlap, which made me miss slightly to the left. Normally when I miss I miss high/low (which is how I missed when I shot the 5 1/2" Bisley) so I'm attributing the windage errors to my failure to center the front sight finely enough with the shorter sight radius.
(A note on "missing": My test targets are 3x5" cards at 25 yards posted in vertical orientation on large cardboad backings. A "miss" is anything off the card when shooting offhand, and partial hits score as misses. I don't shoot groups with my revolvers unless I'm testing loads, and then I do that off a bench).
2. Recoil: Suprisingly, I didn't notice much difference in the recoil between the two guns or much difference in muzzle rise. The fact that both had identical grips and very similar trigger pulls made the shooting feel pretty consistent between the two. The big difference, as noted above, was the sight picture.
3. Handling: Both Bisley's balance beautifully, with the difference being that the 4 5/8" model has a neutral balance whereas the 5 1/2" gun has just a slight forward bias. Not enough to favor one over the other, in my opinion. Both are heavy revolvers, given the amount of extra steel in the Bisley grip compared to standard Flattops.
So, I'm glad I have both but I'm likely going to take the Bisley frame off the 4 5/8" model and have it fitted to my 5 1/2" 45LC/45ACP Flattop and replace it with an alloy grip frame to lighten up the short gun for packing around. With a wider rear sight notch on the 4 5/8" gun I think the practical accuracy difference I experienced would disappear. Might have to look into doing that.
All in all a good day at the range, and there's no substitute for side by side shooting when it comes to making comparisons.