The only thing that really matters, when carrying a 3-4" revolver IWB, is the width of the cylinder. Again, for this, the 3" SP101 or 4" S&W K-frame are the best options due to their narrower cylinders.
True. Though I still carry 3" and shorter guns frequently, simply because they are usually equipped with easier to conceal round butts. And they are a hair more comfortable if sitting a lot. And as for the cylinder width, I agree as well. I really don't find much difference between the 5 shot J Frame and Ruger SP, so I carry 6 shooters IWB, but YMMV.
Actually, given time to acclimate and really good quality gear (like a Lobo Gunleather IWB holster and a Beltman 1.5" bullhide belt), a 4" N Frame like my S&W Model 28 Highway Patrolman in .357 Magnum is possible, though it is not my most frequently carried gun. I carry it when I can though because I shoot this particular gun better than just about any gun I own. Plus, the intimidation factor, though certainly not to be counted on, might be a bit higher with the big blue N Frame than a little S&W 642
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More often though, I carry my 4" Ruger Police Service Six in .357 Magnum in a FIST #20 IWB holster. I paid only $275 for this gun, and it carries very comfortably. It is very accurate in my hands too, though not quite as natural as my M28.
As for 3" guns, I really like my S&W Model 13. I paid $450 for mine 6 months ago, including the original box and papers. That price may have been a little high at the time, but I'm seeing (online) a number of 3" 13s breeching the $500 threshold these days. I've not started carrying it yet, but I'll use a K Frame FIST #20 when I do. Like others, I don't consider 3" K frames snubs as they have a full length ejector rod. As stated earlier, the compact round butt makes the gun extremely easy to conceal, even with just a white T-Shirt.
4" .38s are another option:
Model 10: Fixed sights, blue
15: Adj sights, blue
64: fixed sights, stainless
67: adj sights, stainless
I own a 4" Model 15 that I paid $309 for about a year ago. I carried it pretty frequently up until the time I purchased and proved my Service Six to be reliable. It has since been living in my safe more often, but I still carry it every now and then. I like guns with holster worn finishes, but this one is close to mint and I think I'd lke to keep it that way.
With the exception of the Model 28, all of the above pictured guns can be carried with reasonable comfort by most individuals. The 28 does take more patience, and one probably ought to get used to carrying a medium frame gun for a while first. For me, the 28 is simply too accurate (in my hands) not to carry.
Guess that means I'll be looking for a 4" N frame with a caliber starting in "4" before long
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