I've got both and think the shorter bbl is more convenient and shoots just as well...the 7.5 is a Bisley and I bought it for that reason but if I were going to sell one tomorrow (which I'm not) I'd sell the 7.5 bbl first.
I'm a fan of the shorter barrels...4-5/8" over the 5-1/2"...even that add'l inch seems to be a PITA when seated with the gun holstered on the strong side. All of my holsters have minimum "drop" too. Tractor, riding mower, car seat, and deer stand...they all end up pushing the hammer up in my ribs if I carry one of my 5-1/2"ers.
Too, I don't see any accuracy advantage to the longer barrel...it just doesn't show up on the target for me. Others may have a different take on it and may be using a different type of holster...in particular, I respect rclark's opinion on most anything he comments about and he's a fan of the 5-1/2" as is Dale53, both experienced hand gunners...that in mind, try both lengths if you get the chance and see what you like...
In the attached pic you can see the minimal amount of drop to my rig...I've been around those old Tom Threepersons rigs for almost 50 yrs now and just can't change...
Rodfac, I understand and respect your situation. In my case, I'm 6'3", wear a strong side holster with a 3" drop. That makes it easy to tote a SA with a barrel length up to 6 1/2" without interfering with sitting or any other body position. I do have a SBH with a 7 1/2" barrel and use a dropped Geo Lawrence holster. It does indeed get in the way.
From a theoretical point ... a 5 1/2" will deliver about 50 fps more muzzle velocity than a 4 5/8" with normal factory ammo ... not enough to be a deal breaker but an increase none the less. I have tested many handguns in a Ransom Rest and found factory manufacturing specifications made more difference in accuracy than barrel length, however the "almost an inch" longer sight radius does improve accuracy for some shooters, whereas with well experienced shooters, it probably doesn't matter.
The weight difference between a 4 5/8" and a 5 1/2" is negligible ... what you gain in weight, you lose in balance. So in conclusion, the reason why Ruger makes both barrel lengths is ... just a matter of personal preference. I prefer the looks and balance of a 4 5/8" but I'd rather shoot a 5 1/2". Guess that's why I have several of both.
Iowegan...good points there...and carry comfort is in the eye (dare I say "seat") of the beholder, LOL. Too, where you carry on the belt is as important as drop...I carry on the pants belt some of the time..and on a dedicated gunbelt the rest. I try to wear them at the same height...and my belly overhang helps in that regard. My holsters, for the most part, all have the same drop...virtually none as I make the belt flap fold right at the rear of the cylinder...
Balance is another fine point for differences...in my current Ruger stable, all but one, have steel frames...and that 4-5/8" length balances right where I like it...again, in my hand, and for sure, an aluminum framed gun would put the balance point decidedly farther out...muzzle heavy.
And I should have added you to rclark and Dale53 "respect" list. I look forward to your posts...and would dearly like to see your entire Ruger collection...you've posted some beauties over the years.
Comfortable looking rig, Rodfac... Looks like a reasonably supple 2-1/4" belt. I make most of my own belts and holsters, and generally bend the loop at the top of the cylinder. Unlike you, I sling the belt just below the pants belt. The belt varies 2-1/4", 2-3/4", and 3-inch, always single layer top grain.
The 4-5/8 (or 4-3/4) inch barrel definitely rides better on a tractor or log skidder. 5-1/2" is very nearly as comfortable when using a chainsaw. It is a mistake for a person working or cruising the mountain to wear a Sam Browne type belt of laminated, hard leather, which cuts into the hip bones and hips.
The sexiest Colt Peacemaker has its barrel flush with the ejector housing. To a lesser extent, the same applies to the Ruger and Freedom Arms. Hunting and target revolvers are another aesthetic, at once more specialized and limited.