Gun design questions.

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Depending on whether a SA EMP pistol fits her hand, my wife can't find a major caliber (9mm on up, though the .40 is her favorite) carry gun that is small enough for her hand. If you want to, I'm sure you can find the thread on it from a few weeks ago. Long story short, any pistol with a DA trigger is too big for her, including J-frame sized revolvers.

A full-size 1911 is about 1/4 inch too big for her to get her hands on. We're hoping that the EMP (short-frame 1911 in 9mm) will work for her, but based on measurements from SA, I'm not sure it's gonna work.

So she said to me "you've got a degree in mechanical engineering, why don't you design a gun for me?" So I thought I'd just play around with it and see what I come up with. I do see a lot of threads about women who can't find a gun that fits their small hands. And engraving "Lady Smith" onto a man's gun doesn't make it a woman's gun. Therefore, I'm toying with the idea of designing a woman's pistol from the ground up.

She gave me several things that must be on her pistol.

The pistol must be single-action. She likes my Browning Hi-Power trigger, and the trigger on a 1911, as well as her Colt 1903 hammerless and new Beretta 1934. All single action.

The pistol must have removable grip panels. She likes the idea of changing the style, color, and fit of the grip, like the 1911 and basically all the other guns she likes.

The magazine must be single stack. Any double stack mag is just too big for her hands.

The slide must have a rounded top, like the 1911 or BHP or 1903 or Beretta, not ugly like the Glock or Kahr.

The pistol should be striker fired instead of hammer fired, though this is negotiable.

It is this last item which causes me problems. Most striker-fired pistols are DAO or at most partially-cocked. How would you cock the striker on the forward slide stroke without soaking up too much of the slide momentum which ensures proper chambering?

In a hammer fired pistol, the hammer helps delay unlocking and is cocked as the slide moves back, and the slide moving forward is impeded only by the chambering of a round - essentially all the momentum of the slide is available to push the round into the chamber. However, in a cock-on-closing striker fired pistol, the striker would be cocked as the slide closes, using up the same momentum which should be ensuring that the round is chambered.

But then, a hammer fired pistol can have a weaker recoil spring because the hammer helps delay the unlocking, so the weaker recoil spring chambering the round is exactly the same as the stronger striker-pistol recoil spring being partially cancelled out by the cocking striker.

Of course, that leaves us with a striker fired pistol with a slide that is tougher to rack than the hammer fired pistol. As pax has pointed out though, it still shouldn't be a problem.

Gee, it seems that I answered my own question just by thinking it through enough to type it out. Thanks everyone for your help!

So... any suggestions?
 
It is this last item which causes me problems. Most striker-fired pistols are DAO or at most partially-cocked. How would you cock the striker on the forward slide stroke without soaking up too much of the slide momentum which ensures proper chambering?

Take a look at the Springfield XD line. They are classified as DAO by the BATFE, however, the striker is about 95 - 99 % pre-cocked (Glocks are about 60%), according to estimations I've read. My observations in use agree with that. The XD trigger is a bit long, but you feel it engage right at the end, and then it's a very short travel until it breaks. The XD would be worth handling and seeing how easy or difficult the slide feels for her to rack.

After that it would only be a matter of engineering a similar striker fired mechanism, and shortening the trigger to a true SA pull. A manual safety would of course be a neccesitity, but you already know that. I'm not an engineer, so I don't know how difficult engineering the firing mechanism would be. I would think that would be the hardest part. After that, you're dealing with building dimensions and contours around a single stack magazine. I think that would be the easy part, but you're the Mech. Engineer. Hope that helps you in the potential project.
 
Of course, that leaves us with a striker fired pistol with a slide that is tougher to rack than the hammer fired pistol. As pax has pointed out though, it still shouldn't be a problem.

Naw, slow down a bit. I would still say that an easier slide rack is better than a harder slide rack. A pistol designed around small hands should have the easiest possible slide action commensurate with reliability.

IOW, don't sacrifice reliability for ease of use, but do keep ease of use on the table.

pax
 
The Colt 380 Goverment model is a good size. Not the caliber you want.

Start from there and "work up" if you are designing.
 
Why is she set on striker fired?
Which 1903 are you talking about, the 38 or the 32?
If it's the 32, why not just model the "hammerless" option?
 
It is this last item which causes me problems. Most striker-fired pistols are DAO or at most partially-cocked. How would you cock the striker on the forward slide stroke without soaking up too much of the slide momentum which ensures proper chambering?

It's a balancing game. First thing you need to do is determine how much energy you need to reliably detonate the primer. The .gov says the firing pin needs to indent a copper crusher .0118" minimum. So you need to determine the shape of the tip of your striker. Then make one, set it on top of a copper crusher, and start dropping a ball bearing down a tube onto the back of the striker until you get the indent you are looking for.

Remember, the purpose of the recoil spring is not to slow down the slide, but to strip rounds out of the magazine. The easier it is to strip rounds out of the magazine, and push them into the chamber, the weaker your recoil spring (or the balance between the striker spring and the recoil spring) can be.

Striker fired pistols also offer some challenges in providing a consistent gun to gun trigger pull, because the interaction between the slide and the frame becomes more important.
 
Why would you want to preload the striker on the return stroke of the slide?
If you try this, you will have much less energy (and force) to accomplish your task. By preloading the striker on the back stroke, which is what I believe everyone out there is doing, you are getting the energy from the slide before it is absorbed by the hand.

My opinion on strikers is that they are a way to simplify and reduce the cost of a pistol. Think of all the parts associated with a conventional hammer design and then compare to a striker system. However, this does not mean that a striker system is superior to a hammer system. I prefer a hammer system for a number of reasons that I won't get in to here.

If you are designing a pistol from ground up, good luck! I have spent four years, four thousand hours and an undisclosed amount of money designing and building something that is very close to what you describe - except is has a hammer!
 
Granted all that you say, add an unlimited budget and a skilled gunsmith willing to mess with you...

Take a Kahr K9
Make a new cocking cam that presets the striker at or near full cock which will allow a very rearward relocation of the trigger and shorten its travel to that of a "soft" pull hammer gun so she can reach it.
Design and install a manual safety to make that short action safe to wear.
Build up the top of the slide and remachine into a rounded contour so as to not offend her eye. It will also add mass to the slide and reduce the need for a stout recoil spring.

Plan B. Put on your black catsuits and sneak into the Colt company museum and steal the last prototype of the 9.8mm Colt Auto. It is a 3/4 scale 1911 and should do her very well. That last one was finished out of spare parts with a .38 ACP barrel because they had shot up all the 9.8 ammo in earlier trials.

Realistically, good luck on the ESP. Remember, it is a short reach grip with a long trigger to make it up for men. You would likely have to have the trigger modified to a shorter length for her. Not replaced, it is not a 1911 part.
 
My 2 cents:

If the EMP is close to fitting, send it off to a skilled gunsmith for something like Yost Bonitz's extreme grip reduction package (thins front strap, removes metal from rear of grip frame and under trigger guard, thins customer's stocks, and includes a custom made lowered thumb safety) and custom short trigger. Having something like Novak's "The Answer" machined for the EMP in conjunction with a grip reduction would likely make the grip even smaller. That might get it there, and it'd be a lot cheaper than custom designing your own pistol.
 
I'm a mechanical engineer, and a sucker for designing my own stuff (even if it never sees the light of day).

I was thinking about removing the grip panels (and bushings) from the EMP and slipping on one of those thin Hogue slip-on grips (similar to a section of bicycle inner tube) and maybe that'd work with a gunsmith-shortened trigger. Be worth a shot anyway, have the guys at the gunstore pull off the grip panels.

ABBOBERG, I agree completely. That's what I was trying to say, but you said it better. Except that nobody I know of preloads the striker on the back stroke. How could it be done? I'm definitely leaning towards a hammer fired pistol, but I do like the simplicity of the striker design. If I knew how to preload the striker on the back stroke of the slide, I'd go with that.

Sorry pax, I didn't mean to misquote you. I agree, easier is better. She doesn't want a hammer to get snagged on stuff, but I'm thinking maybe a shrouded hammer like on some S&W revolvers. You can still cock it by thumb but it doesn't get in the way of a draw.

I know that I probably won't ever get around to building one, but I was thinking more likely (though still unlikely) I could sell the concept to a gun manufacturer for a very generous offer (like a small percentage of royalties, and maybe one or two of the first production pistols). Heck, I sold a self-propelled vacuum cleaner design to an unnamed vacuum cleaner company for less than $250. Maybe I've got a chance.
 
What guns can she deal with ? Kahr ? Good gun design IMHO includes exchangeable backstraps like the HK P2000 to fit various hands .Has she tried the HK P7 M8 ? One of the finest pistols I've owned is the Rem M51 , though it's only in 380. The designer took great effort to make a grip suitable for a very wide range of hand sizes.
 
Other Thoughts

Just thought I'd toss out a few more ideas.

- STI LS9 / LS40. Extremely thin, highly modified 1911 platform. Kinda like an EMP without the hype. STI will very likely work with you on short triggers if you talk to them about the situation. Comes stock with extremely thin grips.

- Hammers; Almost all traces of spur removed like on the Kimber Aegis, or ring style like those seen on some BHPs if she needs to thumb cock to to help reduce cocking resistance.

- Grips. See what xMetal did here; http://www.thehighroad.org/showthread.php?t=244273. Maybe just a sheet or two of carbon over the thin plate backer and devise an alernative method to secure them.
 
What guns can she deal with ? Kahr ?

Ha! You make me laugh. The Kel-Tec P32 was too big for her. The Kahr are all Double Action triggers, the tip of her trigger finger wiggles around BEHIND the Kahr trigger. If the Kahr was single action with a short 1911 style trigger, it might work.

The STI appear to be still made on the full-length frame (instead of shortened around the 9mm/.40 cartridge). I doubt those would work.

As for designing a pistol, I'm kinda just toying with the idea. I think I can make a grip that is extremely flexible as to the shape and size, capable of being nearly as small as the magazine itself. Still don't know about the whole "preload on backstroke" striker idea. But I'm writing stuff down, maybe the ideas will take shape in a few years.
 
Think of developing a new pistol as a really fun hobby. Even if you can come up with something that hasn't been built and sold, published or patented before, you would be lucky to get 15 bucks a gun royalty assuming the manufacturer won't find a way around your patent or just decide to steal your design. Most specialty guns, like the micro-gun you are describing, will sell only a few hundred a year (look at Derringer). Kel-tec is the exception, and sells tens of thousands a year, because they are so cheap. If Mr. Kellgren wanted to, he could put out something smaller than a P32, but since a lot of people can barely hang on to it (including me), there would be a very small market for a gun that only the smallest of hands could hold.
 
I think mdao had the most practical solution, but the rest of this is sure fun. :)

pax
 
A bunch of good suggestions already. I would add Walther or equivalent Smith & Wesson are striker fired with different grip backstraps for different sized hands. Not really very color change friendly, though. Same with the Smith & Wesson M&P, all striker fired. There are different action choices among these.

My own personal fave is the H&K P7 M8 which is single action, extremely accurate, very safe to carry and pretty expensive. Fancier grips are available. Some of the other H&K handguns might also qualify based on action choice.
 
I'm surprised that so far nobody has suggested the CZ 75B-SA. This is the single action version (single stack). I have small hands, and there are very few pistols with a trigger that my finger can reach easily. This is one of them, the Hi-Power is another. It's worth a look.
 
This is about the third thread on the subject. EVERYTHING has been suggested. Nothing suits, the lady has tiny hands.
The SA EMP looks like her best chance in a 9mm; I keep promoting the Colt Government .380 but she wants More Power.
 
Racking the slides on hammer & striker-fired pistols

Naked_prophet wrote:
"a hammer fired pistol can have a weaker recoil spring because the hammer helps delay the unlocking, so the weaker recoil spring chambering the round is exactly the same as the stronger striker-pistol recoil spring being partially cancelled out by the cocking striker.
Of course, that leaves us with a striker fired pistol with a slide that is tougher to rack than the hammer fired pistol."

Scandium_Wheelgunner replies:
The slides are equally tough to rack if you cock the hammer when you rack the slide on the hammer-fired pistol.

Consider 2 pistols with similar strength springs:
a hammer-fired pistol with a recoil-spring strength of 10 lbs and hammer-spring strength of 5 lbs,
and
a striker-fired pistol with a recoil-spring strength of 15 lbs and striker-spring strength of 5 lbs.

On the hammer-fired pistol when the slide opens the resistance is
recoil spring + hammer spring,
10 lbs + 5 lbs = 15 lbs.
When the slide closes, the forward force is
recoil spring alone..
10 lbs.

On the striker-fired pistol when the slide opens the resistance is
recoil spring alone
15 lbs
When the slide closes, the forward force is
recoil spring - striker spring
15 lbs - 5 lbs = 10 lbs.

So the result is the same. Both slides take 15 lbs of rearward force to rack, and both slides give 10 lbs of forward force to chamber the next round, and both give 5 lbs of forward force on the firing pin to ignite the primer.

Basically, what you gain on the swings you lose on the roundabout.

But I should mention a couple of exceptions.
if the design of a hammer-fired pistol allows you to cock the hammer first and then rack the slide, and if you do it that way, then the work (= force x distance) remains the same, but the maximum force is less. That is, it is not a tough.
Another exception is those little Berettas with the tip-up barrels where you don't need to rack the slide at all. Not tough at all!
 
Has she tried the 3rd Gen Taurus Millennium Pro PT111 in SA/DA yet? (or any of the Taurus pistols with the SA/DA mechanism)

Many of her grip issues are probably mitigated by having a SA trigger that starts in a more rearward position.

My understanding is that the Taurus pistols default as SA striker guns (the 809 or OSS has a hammer AND a decocker/safety) which turn DA only in case of a failed primer. The PT111 is a little under the size and weight of a Glock G19, which should be very carry friendly.

If grip is the main concern, then the solution seems obvious to me... she needs to adjust her tastes to accommodate owning a revolver whose grip can be manipulated to fit her hand exactly as she desires.
 
People should shoot what they're comfortable with but it might be useful to discuss with her the ballistic trade-offs between 9mm and .380, especially with modern self-defense type ammunition. There's not all that much practical difference. (Enough difference to support man-centuries of gunboard discussion, but in terms of being shot by one of each at 15 feet, it's nil; ask anyone who's tried). There's certainly a difference in the available sizes of guns for the two rounds.

It's kind of like the difference between carrying a revolver and an autoloader with a big magazine: more might be better, but if you can't solve your troubles with six rounds, another eight probably won't help. If .380's not enough, 9mm is likely to be undersized, too! (You have maybe werewolves in the neighbrohood? Bears?)
 
small hands

one of the big name companies, i think springfield just came out w/ a 3" GAP 45 with the mag/grip sized down to the smaller length of the gap cartrage.....there's your 1/4 inch. They reinvented the wheel for you.
 
What?? If the Kel-Tec P32 is too big for her hands then what pray tell could possibly ever fit them? You want a 9mm with a soda straw for a grip?

I think this is impossible, unrealistic. Just for comparison, what type of object CAN she grip comfortably? I can't think of many things smaller than a P32. Is it the trigger reach or te grip itself that is the problem?
 
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