40 S&W 4 shot J-frame

Ronny99

Member
Joined
Jul 1, 2010
Messages
6
Reaction score
0
With a short barrel the .40 S&W has greater energy than the .357 magnum. The four shot revolver has proven to be a seller with the Taurus Judge. I'm requesting that S&W test market a four Shot J-frame in a serious .40 caliber. This revolver will directly compete with guns such as the Kahr PM 40 and have the advantage of perfect reliability.
 
Register to hide this ad
Interesting...
Minor nitpick, the Judge is a 5-shot.

I do wonder about how cylinder advance and timing would be handled with a four-shot cylinder, though. Having to rotate through 90 degrees for each trigger pull is going to mean the hand has either a fairly long travel, or a short travel with a relatively high effort to do it. It also seems to me that there would be significant wear issues with the hand and pawls...
 
Never mind the cylinder, you can't put a .40 barrel into a J-frame and have any metal left to hold it.
 
I'd be interested in a 5 shot .40S&W J-frame. I don't think the cylinder would be too fat.

There is only one size cylinder for J-frames, they just bore different size holes in them. The issue isn't that the cylinder would be fatter, it would be the same size but the walls would be too thin for the pressures. That's why they made the 646 with a titanium cylinder. There was so little metal left over after boring 6 .40 caliber holes in an L-frame cylinder it wasn't strong enough, so they went with titanium.
 
I like the way everyone's thinking so far. A 5 shot K-frame seems like it would be too big to comfortably pocket carry unless you have cargo pants. I own a K-frame model 67 with 4 inch barrel and even it it were a snub I can't imagine pocketing it. My 642 j-frame is just small enough it pockets easy and doesn't print the way an auto does. A larger gun just wouldn't do and I think would lose that market segment. I know in my gut if they could do a 4 shot .40 it would sell more than enough units to make it viable for at least a few years until a secondary market sprouts up. If it were 5 shots in a larger frame I think it would still sell some, heck look at that Taurus judge, 9 inches long, and it sells. I just don't see the larger k-frame selling to the type of consumer that I am, which is a CHL holder that has to be discreet and can't afford to be "made" carrying at the office or around town.
 
The attached picture is a great example of a 646 performance center. It is a masterpiece of workmanship and style, but was a horrible marketing disaster. The problem with it was zero CCW interest and negligible interest from most gun guys due the extremely high performance center price premium.

What I envision is smaller, concealable, has a reasonable price point, and reliable CCW weapon. Avoiding the mistakes of the past is easy as long as we know what they were. Thinking about what this revolver could be and the comments thus far has me thinking that a .40 in a J-frame may not be technologically feasible. I'm not a machinist or engineer so I can't comment on those specifics. I do know it is possible to engineer a gun no larger than the size of a colt detective special to fill this niche with either a 4 or 5 shot capacity in the cylinder. If such a weapon is produced I do believe it would sell reasonably well to the CCW market.
 

Attachments

  • s&w.jpg
    s&w.jpg
    40.5 KB · Views: 51
I'm at work so don't have my calipers handy, but here's the rough numbers coming to mind:
A J-frame cylinder is ~1.30" diameter.
If we go with a 4-shot design, that leaves less than .50" for the center hole with ejector and the chamber walls.
If the center hole is 0.25", we've got about 0.20" for the total chamber wall thickness, or 0.10" each. From that 0.10", the cylinder latch points have to be machined in, and those are probably 0.05" deep... leaving 0.05" inside and out to hold the pressure of a .40S&W (35,000psi SAAMI spec, same as a .357Mag). If the chambers were not 180 degrees, it *might* be possible, but that moves it into a 5-shot K- or L-frame.

For comparison sake, all other things equal, a .327FM cylinder is six shots so the latch points are also right over the cylinders... but there's an extra .08" or so of space to work with.

With some crazy metallurgy work, and super careful machining, it might be possible... but honestly, for the effort and cost that'd be involved, I'd stick with a 5-shot .357 or .38 +P.

Snubs (particularly J's) are a tradeoff, but I bet you know that already. They're easy to conceal, but that means limited shots and cartridge diameter. If you really want a .40 deep-concealment CCW, the Kahr PM40/MK40 models are tough to beat: 5/6+1 capacity, 0.9" thick, an inch shorter than a J-snub, and comparable weight (16/25oz empty).
 
zercool,

Thank you for that information. You're more technically astute in this area and I learned a lot from your post.

Regarding the Kahr PM brand I've had a bad experience and don't trust them. I meant to replace my 642 with a bigger caliber. I spent almost $800 for a Kahr PM45 with the diamond black finish and night sights. I am a 45 guy and all things being equal a 45 makes a larger hole. The PM 45 is roughly the same size as my J-frame and I have a pocket holster that makes it print like a large wallet or blackberry. The problem is that when I was doing the 200 round "break in" with standard pressure 230 grain fmj rounds I had issues with failures to feed. The round would end up at an angle against the feed ramp with the slide closed jamming it. This was not the big problem though. At around round 160-165 I started experiencing a failure of the trigger to reset. This became progressively worse until about round 185 when the trigger would not reset at all. I had a heck of a time even cleaning it because you need to pull the trigger when it is reset to remove the slide. I've learned on other forums that the trigger reset is a failing common to the PM line. Right now the gun is back at the Kahr service department and I'm waiting for it to be returned or replaced. I can not trust this gun, even if they replace it with a new one, to be reliable enough for carry. I don't want to get killed for lack of shooting back. At this point I'm not trusting the extremely small small autos in a serious caliber, expect for maybe a Glock, and the G27 size Glock is frankly too large for my pocket and I'm hesitant to IWB carry one for fear of an accidental discharge while holstering, as happened to a student of my CHL instructor.
 
The Glock 27 is an ideal gun for IWB carry, I've been using mine that way for almost 15 years. Any gun can have an AD if handled incorrectly. The key is ALWAYS keep your finger off the trigger and out of the guard, especially when holstering, unless you are planning to fire. No amount of safety features can override poor gun handling. If you follow the four basic rules of safety you should be fine.
They are as follows:
1. There is NO SUCH THING as an unloaded gun. Even if there are no cartridges in it.
2. Never let the muzzle cover anything you are not willing to destroy.
3. Keep your finger off the trigger until you have made the decision to fire.
4. Be absolutely sure of your target and what is front of and
beyond it.
Most of us who have been handling guns for years know these rules. They work. I wish you all the best.
 
Back
Top