Hi all,
Just wondering if a K frame barrel can be put into an L frame ?
Specifically a model 65 4" heavy barrel into a 686.
It would be done by a "real" gunsmith.
Thanks.

I would be inclined to say no. I just checked the barrel stub diameter inside the frame on my L frame 620 and it measures 0.523 inch, on my model 67 the same point measures 0.497. In addition, the K frame barrels have a flat machined on the bottom to clear the gas ring for the cylinder. That flat is a weak area on the barrel that limits the choice and use of 357 Magnums in a K frame. To be blunt, while the threads used might be the same, it's NOT a good idea.

From the sound of it, what you're looking for is a 686 Mountain Gun. It just happens that Lipsey's is currently having a sale on the 686 Mountain Gun, which would lead me to believe that they may still have some in stock. You might want to give them a call and locate a Lipsey's dealer near you. Following is a link to the listing.

Smith and Wesson 686 Mountain Gun 357 Magnum | 38 Special - SM150862 - LIPSEYS.COM

Thanks for the info.

Unfortunately I'm in Australia, so things aren't that simple :-(
I was really just thinking out loud.

If all goes well I'm getting a M65 that will probably be rebarrelled, and I was wondering if the original M65 barrel would go on a 686 frame as an easy way to get a 4" 686.

Stainless 4" guns are fairly hard to find down here.
Trying to get a stainless K frame is even harder!!

As noted, the barrel shank diameters are different. They are NOT interchangeable.

In addition, the dimension from bore centerline to extractor rod centerline is larger in the L frame, and the one will not fit the other.

john traveler has it right about the extractor rod to bore centerline dimensions being different. Some time back having more time than sense, I installed a L Frame 2.5" barrel into a Model 66. It was far more machining effort than was justified. I would not do it again. ..... Big Cholla