If you conceal carry a K, L or N frame revolver, and also shoot it in Defensive Pistol Matches for practice, you will quickly figure out what the Big Deal is.
I carry a 2.5" 66 No Dash, a 3" 625, a 2.5" 310NG, as well as a few 4" revolvers. I carry them all in Lobo Pancake holsters.

I have found that the 4" guns are harder to conceal due to the longer barrel length, as well as larger grips. I have wood round butt finger groove combats on all my 2.5 an 3 inch guns. I have the larger size finger grooves on my 4" guns.

With the 3" 66 the additional 1/2 inch of barrel probably does not add enough sight radius over the 2.5 inch to make a big difference. The longer ejector stroke however is a really big deal doing a reload.
The 2.5" and 3" K Frames are a very handy size for concealed carry, as well as being a very shootable size platform. The 3" guns are the Top Choice because they have the full length ejector of the longer barrel revolvers.

Bob

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