Wheelgun Wednesday: Homemade Modifications To A S&W 625 JM

    Homemade modifications of S&W 625 JM

    TFB reader, Steve, contacted me after seeing my recent review of the Smith & Wesson 625 JM .45 ACP revolver for the TFB Wheelgun Wednesday series.  He had purchased the same model for his wife, but ended up doing several modifications to customize it to their liking.  Steve gave permission for me to share his photos and process with you.

    modifications to a S&W 625 JM

    Factory S&W 625 JM as tested and evaluated by the author.


    For those that are familiar with the S&W 625 JM, you may have noticed the spurless hammer.  S&W’s factory rigging of the 625 JM only comes with a spurred hammer that allows for double action or single action firing.  Since Steve bought this as a defensive, nightstand gun for his wife, “double action” was the name of the game.  Steve documented his process on the Brian Enos forum, of which you can read several excerpts about the hammer modification below:

    I’ve read every post multiple times about cutting hammers to allow for lighter trigger pulls while still maintaining reliable primer ignition. I was inspired by 4mike’s work on his hammers and decided to let my Dremel loose. How difficult could it be, right? Famous last words.

    I knew from my reading here that I had to reduce the weight of the hammer by half in order to achieve nirvana. Needless to say, since the Dremel was impatient to begin, I failed to weigh the hammer prior to beginning surgery. Luckily, I had also read that the final weight of the hammer should be between 250 and 260 grains.

    When I’d finished, the hammer by itself weighed in at just a smidge under 300 grains. Not good enough! But where else was there material that could be removed? I wanted to maintain the funtionality of the external safety lock and I didn’t want the hammer slot in the frame to be a gaping hole. So, I fired up the Dremel and ripped through the top of the hammer. When I threw in the towel the hammer was down to 268.8 grains as measured on my Dillon beam scale.

    Homemade Modifications to a S&W 625 JM

    Homemade modifications to a S&W 625 JM

    Steve also changed out the factory sights and did a lot of internal work to lighten the trigger pull, while still maintaining flawless functionality.

    I added an SDM .250″ fiber optic front sight and a Weigand rear sight blade to the revolver. The JM grips were replaced by a set of Hogues from which I had to remove the lower finger ridge since it did not comport well with my wife’s hand.

    I also substituted in a Wolff Type 2 – Reduced power Power Rib mainspring and an 11 lb rebound spring after I’d spent several days smoothing everything I could find in the action that rubbed against anything else in the action. As an aside, I knew a gunsmith in Austin in the early 80’s who told me he smoothed revolver actions by filling the mechanism full of toothpaste, puttng the sideplate back on, setting the gun in a home built fixture that allowed the trigger to be pulled repeatedly by a small motor, then letting the motor run for however long.

    Steve guessed the new trigger pull weight was around half that of the factory trigger by the time he’d finished the project.  You can read his original forum post HERE.  Steve did have a few teething problems with certain brands of ammo, but he eventually got everything hammered out.

    Personally, I’m a little leery of modifying a defensive gun too much, but I’m quite impressed by Steve’s skill, patience, and determination.  I have crudely cut a hammer’s spur that was too sharp from being chipped, but removed as little material as possible.  What do you think of Steve’s homemade modifications to his wife’s S&W 625 JM?  Feel free to share some of the mods you’ve done as well.


    Doug E

    Doug has been a firearms enthusiast since age 16 after getting to shoot with a friend. Since then he’s taken many others out to the range for their first time. He is a husband, father, grandfather, police officer, outdoorsman, artist and a student of history. Doug has been a TFB reader from the start and is happy to be a contributor of content. Doug can be reached at battleshipgrey61 AT gmail DOT com.