I don't find them that different, but perhaps I'm not perceptive enough. An L-frame is basically a K-frame grip with a larger frame than a K, but smaller than an N, originally meant to handle .357 magnums better. The proliferation of different calibers, materials, add-ons, and ring-dings over the years have caused the numbers to blossom.
S&W numbering is confusing if you're new to them, because they make so many models.
But, an L frame is an L frame - same size/dimensions. It's the first number that lets you know the material the frame is made out of:
386 - the 3 means the frame is made out of aluminum with a little scandium added.
586 - the 5 means it's blued carbon stuff (i.e., the good stuff to us old guys
)
686 - the 6 stands for stainless steel frames.
The last two numbers will tell you the caliber or sight arrangement.
696 - stainless L-frame in .44 caliber. Or 396 - aluminum L frame in .44 caliber. 686+ - stainless L frame in .357 with a 7 shot cylinder instead of 6. 581 - carbon steel L frame with fixed sights.
After a while you get used to it. Then you can start making posts with just a quick reference to a number, so you can confuse 50% of the readers, and let everyone know how cool you are.
I'm doing this off the top of my head, and others will probably add more. Like the rarely seen 242, where the frame is aluminum, but the cylinder is made of titanium. Or the 646, a stainless steel frame in .40 S&W with a titanium cylinder.
The important thing is an L-frame is an L-frame - same size and dimensions, although S&W did change the arc from the top of the frame at the rear sight to the top of the grip at one point.
Hope this helps, I need to get a drink.
