MAG-NA-PORT’S Custom S&W 640 Magnum


First, as many GunsAmerica readers may know, I am a self-avowed, unapologetic, fan of the Smith J frame series of revolvers. I have carried a J frame, of one model or another, on a daily basis for more than forty years. They weren’t just carried. I put a lot of rounds down range over the years during agency qualifications and personal training. Over the years, I have also come to have an appreciation for custom pistols and the gunsmiths that do such creative work.

Being in the industry since 1984, I have had the pleasure of meeting many great people. One of those was Larry Kelly. Larry was a well-respected writer and renowned handgun hunter. Larry was the first hunter to take Africa’s Big 5 with a handgun. Larry also founded Mag-Na-Port International. Larry passed away in 2010, but his son, Ken, has continued his legacy and grown the business. Ken is one of those people who never meets a stranger and is very humble. He is also an extraordinary gunsmith.

What is Mag-Na-Port

Mag-Na-Port is a process where trapezoidal ports are cut in barrels using Electrical Discharge Machining. The process is very precise and does not damage the surrounding area or leave any burrs or machine marks. The ports vent gases upward which, in turn, reduces muzzle rise during recoil. Mag-Na-Ports do not reduce velocity, affect accuracy, or increase the report of the firearm.

The company offers a large number of services that include various port designs as well as custom gunsmithing options. For the past several years I have wanted to do a project with Ken. I was really waiting for the right pistol to send to him. When I received a new S&W Model 640-3, I knew the time had come.

This is the stock Model 640-3 that I sent to Mag-Na-Port. The makeover is stunning.

The Centennials

The current Model 640 is a J frame, five-shot revolver, chambered in .357 Magnum. It features the completely enclosed hammer that S&W first introduced, in 1952, as the Centennial. The Centennials were offered with both a steel frame and an alloy frame and, in 1957, they became the Model 40 and Model 42 respectively. Both were discontinued in 1974.

In 1989, Smith resurrected the Centennial, with the stainless Model 640 that was rated for .38 Special +P. In 1996, Smith redesigned and strengthened the J-frame to accommodate the .357 Magnum cartridge. The Magnum Centennial was designated the 640. The Magnum J-frames are most easily identified by the longer, 2.125” barrel and the underlug that encloses the ejection rod.

The Mag-Na-Port custom is shown with an original Model 640 that is chambered in .38 Special and rated for +P. Note the longer barrel and strengthened frame on the magnum model.

The factory finish on the 640-3 is best described as semi-polished. The 640-3 weighs in at 22.1 ounces and is 6.5” in length. The trigger pull, while heavy, is smooth and the MIM trigger is void of any sharp edges. The front sight on all Magnum J frames is a pinned serrated black ramp. The pinned design makes replacement very easy. The soft rubber stocks are reminiscent of the old Smith banana grips and extend below the frame. Smith & Wesson 640 Factory Page

Designing a Custom Centennial

First off, I like the sleek lines of the Centennial and did not want to do anything that would detract from the pistol. I also wanted to show off the capabilities of Ken and the Mag-Na-Port shop. After talking with Ken, we came up with a build that was stunning but still very practical as a daily carry and personal defense handgun.

The 640 received a matte bead blast finish that is attractive and non-reflective.
Side plate screws were polished to a bright finish and a narrow band was polished around the back of the cylinder.
The MIM trigger was rounded, smoothed, and polished to a mirror-bright finish.

My first request was to bead blast the entire gun to give it a matte gray finish that was both attractive while being non-reflective. The second item on the build request was to do a deep inverted crown on the muzzle. This is a nice custom feature but also serves to protect the bore from damage. To complement the matte finish, Ken polished the sideplate screws and the thumb piece screw. He also polished a ring around the rear of the cylinder. This prevents the cylinder stop from creating a drag ring and is also attractive.

The matte finish reduced excessive glare on the top strap and barrel.
The chambers were polished, chamfered, and numbered.
The factory front sight blade was replaced with an XS Standard Green Dot with a Tritium insert.

Going inside the pistol, Ken polished the appropriate parts and installed a lighter mainspring. To add to reliability, he installed a longer firing pin that was supplied by Cylinder & Slide. He also recut the forcing cone, honed the chambers, and chamfered and numbered the charge holes. The chamfering assists in reloads and the numbers are simply a nice custom touch. The factory front sight was replaced with a green XS Standard Dot with a Tritium insert. This is an easy modification since the factory sight blade is pinned in place. The result is a stunning little blaster that is suitable for a black tie event. He took the ugly MIM trigger and rounded the edges and polished it to a high polish. As a final touch, The Mag-Na-Port logo is etched on the sideplate.

The author installed a set of high horn custom stocks from Craig Spegel. Unfortunately, the wait for new Spegels is well over a year.Spegel Grips

A custom pistol requires custom stocks. I was fortunate to have a pair of Craig Spegel high horn boot stocks put back. They completed the transformation and are the perfect stocks to compliment Mag-Na-Port’s work. Unfortunately, Spegel stocks are extremely hard to obtain and his waitlist is over a year. Other options would be Altamont J Frame Stocks or Hogue Grips.

Range Time

On the range, I kept the shooting to .38 Special +P ammunition. I have shot Magnum loads from a J frame and it was harsh for both me and the pistol. Recoil was punishing and, regardless of what Smith chambered the 640 in, magnum loads are totally impractical for personal defense. However, for those who must know, Speer’s .357 Magnum 125 grain Gold Dot Short Barrel load averages a blistering 1,232 fps, from my Model 640 Pro.

The author shot his standard 5x5x5x2 drill using Speer Short Barrel Gold Dot ammunition. His score was a disappointing 98/100 after dropping a round in the eight ring.

I personally prefer a +P load that is specifically formulated for short barrels.

I chronographed three of the most popular personal defense loads through the 640, with the following results. It is important to note that not all loads will hit to the point of aim. Both the Speer and Federal loads hit close to the point of aim while the lighter Hornady load shot approximately 3” low at 10 yards.

LoadAverage VelocityAccuracy
Federal +P 130 gr. Micro HST834 fps2.2”
Speer +P 135 gr. Gold Dot Short Barrel905”3”
Hornady +P 110 gr. Critical Duty880 fps3.5”
Velocity measured at 10 feet/Accuracy from 7 yards

To Port or not to Port?

So, what about the ports? I shot my 649-5 as a comparison to the ported 640-3. Recoil and muzzle rise are both subjective and subject to grip, pressure, and the size of the hand. Being as consistent as I could, I found that the porting reduced muzzle rise by about 25% or so. This reduction was especially noticeable when shooting timed drills. When fired from a close retention position, the blast from the ports was noticeable but was not debilitating and I was not struck by any powder or jacket fragments.

Mag-Na-Port ports are trapezoidal ports that are cut using an EDM process. This photo also shows the recessed crown on the muzzle.

The XS dot front sight takes some getting accustomed to. The dot is approximately twice the diameter of the rear sight notch. For close distances, inside 10 yards, the bottom of the dot ring can be placed in the rear sight notch. The hits will be slightly high but well within the vital area. For more precise shots, the Tritium insert is centered in the rear notch, with the lower half of the dot concealed.

Final Thoughts & Carry Options

The Garrity Gunleather IWB holster is made from horsehide and trimmed in alligator skin. It is the perfect holster for a custom pistol.

Part of the joy in owning custom pistols is sharing them with your friends. The Mag-Na-Port 640 turned heads at the range and with my friends. Of course, a custom revolver deserves a custom holster. I carried the 640 in a custom IWB holster from my friend, Mark Garrity. The rig shown is gorgeous, comfortable, and durable. Garrity’s Gunleather

I wish to thank Ken Kelly and the entire crew for providing me with a truly custom revolver that will become a family heirloom. Mag-Na-Port offers a wide variety of options, port designs, and gunsmithing services. Visit them at Mag-Na-Port.

The 640 proudly wears the Mag-Na-Port logo that is etched on the sideplate.

{ 32 comments… add one }
  • charlie December 27, 2021, 8:58 pm

    no loss of velocity? so a free lunch?

  • Larry December 25, 2021, 10:10 pm

    Rob? I love the revolver because of what Magnaport and Ken did. My 640 will be headed that way in March. Thank you for a great article

  • swimmer December 13, 2021, 10:51 am

    Bought my J frame S&W model 60 around 1980. Didn’t have any custom work done on it except for painting the front sight with some red fingernail polish.

  • Dexter Winslett December 13, 2021, 10:09 am

    Will not buy a Smith with a Clinton hole.

  • Mike in a Truck December 13, 2021, 9:00 am

    Those that have a beautiful revolver and holster made then stick it in a inside waistband must be hit with a wet mop across the chops. No wait, a wet mop thats been used to mop the floor of a public toilet that has overflowed. Take that hider of nice things. Pow!

  • Dave October 22, 2021, 11:38 pm

    I have a j frame 442 that’s been Magnaported. It is one my carry rotations and I love it. Mine was blued but now is cerakoted black. You ave a nice looking firearm there and congrats! Thank you for a well written and informative article.

  • jim October 19, 2021, 8:39 am

    After owning and shooting a lot of moon clipped ammo I have determined that I would like a J frame (owned mine for 50 years), that was fitted for moon clips and chambered in .38 super. Ported as well. Good write up.

  • Willie-O October 19, 2021, 2:36 am

    I’ve always been extremely partial to S&W “pre-locks”. I’m “old school” – ok, old. If I want a gun “locked”, it will be in my safe. Otherwise I’ll be carrying it. I will never own a S&W with the internal lock – purely a personal choice and political statement made with my money. That said, I do have a mint condition model 629 with a Magnaported 4” barrel with all the desired features – red ramp from, white outlined rear, etc. Love it almost as much as my model 657 with 3” barrel, although it’s factory original. Also have a model 36 “Chief’s Special” with 3” barrel. Like I said, I’m partial to my S&W “pre-locks”. Anyway, that’s a damn good looking piece – love the upgrades. Thanks for sharing it with those of us still appreciate the classic wheel-guns (with or without the locks).

  • FirstStateMark October 18, 2021, 9:29 pm

    As an owner of the 640-1 made in 1999, all I can say is that being 66 years old, shooting factory 357 magnums hurts like hell. After 3 rounds I had to put the damn thing down. After I got the feeling back in my hand, I fired the last 2 rounds. OUCH! Shooting 38 specials are much nicer.

    • Garrett Rob October 21, 2021, 10:34 am

      I’m right there with you Mark. I’m old enough that I have nothing to prove and I don’t shoot guns that hurt anymore!


  • Somebody else... October 18, 2021, 5:55 pm

    I have a few S&W’s J-frame included…. It is an easy modification to remove the lock mechanism and install a plug. I did this to all of my Smiths… keep the locks around to re-install in case you have to send them in for warranty work. We shouldn’t have to do this after all these years but I enjoy working on them and find this level of modification needed to be acceptable…

  • Michael Kemble October 18, 2021, 2:18 pm

    I Have a 357 mag Ultra light J frame (about 14 oz.) S and W. As a small frame “person” I like the pistol and always carry it usually on ankle or IBW. I have to say that I have long since learned that a controlled 38+p is a much better load to use for carry. The 357Mag is EXTREMELY painful for my slight frame (ok skinny) arms and wrist. I can shoot them but I can have much more control with the lesser load. I have to admit though…. the 357 mag out of a 1 3/4″ barrel makes a hell of a lot of noise and about a two foot flame out the barrel. Enough to scare someone without actually having to shoot them!!

  • Edgy October 18, 2021, 1:53 pm

    It looks like the handle is made for right handers . Does it come with left hand wood grips ? Tks

    • Garrett Rob October 21, 2021, 10:36 am

      Thanks for the question. The stocks are relieved on the left side to facilitate reloading, especially when using a speed loader. They work for left and right handed shooters.

  • OldProf49 October 18, 2021, 1:38 pm

    Sorry, Rob, I just can’t make the numbers work. Approximately $800 for the Model 640-3 and $500-ish for the Mag-Na-Port work. That’s over $1300 for a beautiful gun that doesn’t do anything more than my $500 model 642 38 special or Ruger LCR 357 or SP101 does. I like j-frames but that’s too much money. And the polished ring on the cylinder didn’t prevent the obvious turn ring. Check the pictures. (Why doesn’t anyone time revolvers correctly anymore?) Complements on the Spegel stocks and the Garrity holster.

    • Garrett Rob October 18, 2021, 4:36 pm

      I understand. Custom firearms are a very personnel choice much like cigars and scotch. Right now, you could almost buy a new 642 for going price of the Spegels alone. Fortunately, I got them several years ago for a fair price. I should have said the polished cylinder ring minimizes the turn ring.

      Thanks for the comments.

  • Jeremy October 18, 2021, 11:12 am

    As a big fan of S&W revolvers and the proud owner of K, L and N frames, at the moment I–oddly enough–do not own a J-frame currently. That will change one of these days, however, and the 640 Pro Series is right up there at the top of my list.

  • Frank October 18, 2021, 11:07 am

    I still have a Model 60 that I purchased in the early 90s. It’s among the few guns that I won’t part with until no longer breathing. Back in the day when many Federal officers were still carrying wheel guns, most were loaded with the “Treasury Round”. This was a .38 +P+ topped with a 110 gr. JHP. We carried the Model 66 as our duty gun, and the Model 60 was an approved backup. Although S&W didn’t PUBLICLY recommend the use of +P+ in the 60 (was restricted ammo anyway), Uncle Sam had assurances the little J frame would handle them… and it did! At least tens of thousands of Treasury Rounds were sent downrange from the 60s with no apparent ill effects (that I’m aware of at least). Modern improvements notwithstanding, the original J frames in stainless steel were/are TOUGH little guns!

  • Todd October 18, 2021, 10:52 am

    Having a much-loved 340-SC, I found the write-up very interesting.

    Most anyone who’s honest about them will admit that .357 through them is astoundingly abusive.

    In that case, I reload .357 cases to a generally agreed upon “+P” performance with the mandated minimum projectiles.

    That little Smith is my favorite drop-in-the-pocket gun and has been a true back-up as well for many years.

    I like th notion of running it through Magna’s outfit but will have to ensure that they will mess with stadium Smith’s as well.

    Your finish, the sight… most particularly the crown really struck me. I think I’ll opt for polishing the cylinder flutes and crown rather than the drag-ring sing the drag shows up in any case.

    I think I’d like them to bevel the chambers as well, as with only 5 rounds, I like to carry a speed loader. Hell, maybe even have mine cut for moon clips!

    In any case – your fine write-up has got me to thinking.


    • Garrett Rob October 18, 2021, 7:10 pm

      I think you will be pleased. Please mention the article if you don’t mind.

      • Todd October 20, 2021, 3:16 pm

        I certainly will mention it.

        I’ve been waiting for a bit more impetus to get mine customized making it something of a family *legacy* gun.

        A CCW *bar-b-que* gun, if you will.

        Let’s Go Brandon!


  • Charlie October 18, 2021, 10:36 am

    Would be very nice except for the Clinton hole in the side of the frame.

  • J October 18, 2021, 10:09 am

    As someone who carried a Mag-Na-Port .357 2 3/4″ Ruger Speed Six in the ’90’s, DO NOT fire it from a retention position. Personal experience, it was on a range, and it sucked. Otherwise, it’s a fine idea.

    • Jay Smith December 13, 2021, 7:47 am

      When you say ” retention” position. Do you mean welded/close to the ribs or hip ? ( if the action is that close , rotate the revolver on it’s bore axis so your ports point away from your body ) , which also naturally points the barrel “in” towards center mass of a close target … It’s what i do anyway, even without ports.

  • Ruger9 October 18, 2021, 9:18 am

    Well, aparently there are “jerks” in this world but the great thing about this country is that a jerk does not have to “accept” a firearm they are not happy with. And jerks have a right to say so (at least for the time being). For me personally, this is a great option to consider and I expect to be sending mine off to Mag-Na-Port soon.
    Great article Rob.

    • Garrett Rob October 18, 2021, 9:49 am

      Thank you for the kind words.

    • Garrett Rob October 18, 2021, 9:54 am

      Thank you for your kind words. I’m glad you enjoyed the article.


  • C J October 18, 2021, 7:50 am

    Love the J-frame. Was playing around with my 442 yesterday. Installed a Wilson spring kit & new Hogue stocks. I’d like to send my 2.5” M66 off to Magna-Port. Looked on their site quite a few times. Not too expensive either. Great article.

    • Garrett Rob October 18, 2021, 9:51 am

      Thanks. I don’t think you will be disappointed. Please let them know you saw this article.


  • doug October 18, 2021, 7:41 am

    I have a 640. I have had it for several decades. it is fine as is. I shoot it with 125 gr 357’s. It does bark.

  • Donald Chapman October 18, 2021, 6:46 am

    I carried a S&W model 10 as my off-duty for many many years. Because of the similarity to my service revolver. I really appreciate this article. I may have to employ the services of Mag-Na-Port for my next wheel gun.

  • Kb31416 October 18, 2021, 6:35 am

    I guess that i am a jerk, but I will not accept a firearm with a Hillary hole, and the fact that S&W still includes this disgraceful disability indicates that they are a long way off from repentance for their egregious sin against gun owners.
    It’s a shame that Magnaport wasted their work on polishing that turd 💩.

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