OWB buys you two things.
1. You won't need different sized pants. If you carry a compact, slim gun in a good holster, you can probably get by with your current pants and maybe only change the notch you use on your belt. But a full-sized gun, is going to take up a good bit of room in your pants. Unless you wear your clothes pretty baggy, you may need to buy some larger pants.
2. Comfort. A good holster makes a big difference, but I've never worn a holster that was as comfortable against me as a pair of pants is. Having the pants between you and most of the gun/holster combo helps a lot with comfort.
IWB buys you ease of concealment.
1. Your cover garment can be a lot shorter. Your cover garment needs to come down 6" below the bottom of your gun/holster rig to insure concealment when bending/sitting/stretching. With a full-sized gun carried OWB, you're talking something that is closer to a short dress than a long shirt.
2. The pants sort of smooth the outline of the part of the holster/gun combo that is inside the waistband meaning that really only the top of the gun/holster have to be concealed. That's higher on the body and it doesn't stick out as much. The grip will still sort of poke out, but at least the bulk of the gun is pretty well hidden.
I'll a few add items, but keep in mind, there are a lot of very experienced guys on here with differing opinions....which ever you go with, give your choice plenty of time in training before giving up...it'll save you accumulating a lot of unused holsters not to mention $$$.
1. OWB will also keep the bulk of your body sweat off the gun. Many of my short guns are old blued steel and wood which don't take kindly to sweat over an all-day carry session.
2. Too, the gun/holster when worn inside the pants/belt wears the fabric more than an OWB holster/gun combination. Ask any LEO in plain clothes about the wear patterns on his clothes.
3. Comfort is a big item for all-day carry, as John pointed out...not comfortable, eventually leads to 'I don't want to carry'...in my case, and maybe yours as well.
4. As to bbl. length/gun size...I rarely change out guns when headed for town and routinely carry up to 4" bbl'd Smith M19/66 K frames. It's the holster that matters with guns this size....ones that ride high enough to allow reasonable concealment and still don't hinder your draw/presentation movement. An Askins Avenger as produced by Bianchi, El Paso Saddlery, et al; makes a good rig for both revolver and auto. And it'll pull that grip back into your side minimizing 'printing'.
5. Lastly, a good OWB holster allows you
to get and maintain a firing grip on the gun BEFORE it comes out of the leather & without allowing the muzzle to cover any of your essential anatomy. This equates to 'no fumbling' for a better hold as the gun clears the holster, during the draw. While training helps with an IWB in this regard, (and one of my sons carries IWB habitually), it was a frustrating time of it when I tried the system for over a year. When he and I practice CC use here on our farm, every time I watch him re-holster, it gives me the willies...that muzzle is awfully close to much of his anatomy. And AIWB is whole different level of worry.
I went back to the OWB with sheer delight...and dress around the gun. A shirt tail or jacket/suit coat is more than enough cover. John suggests 6" is necessary to hide a gun when sitting or reaching...I don't have that problem but I carry in holsters of my own make and adjust the amount of 'drop' for each gun; two to three inches below the belt is easy to hide. YMMv and Best regards, Rod
