Amazing!!!!!!!!!!!!!

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Hey Tuner, what you are describing is not double blind -- maybe you did it, but just have not described it, here.

I just wish we were closer together, we could set up a test in short order to prove this thing one way or another. Basically, neither the shooter nor the person administering the test can be allowed to know which gun is which. Then, in a random manner, the shooter(s) fire the weapons and try to identify which is which. Enough rounds must be conducted to allow enough guesses to be made to determine if there is a statistically valid pattern (can you really tell which is which, no foolin'?) , or if it is just guessing (which would be my guess!).

And I would even be willing to wager a shilling or two on the outcome!!!!

:p
 
I wouldn't think it would be that hard to check measurable recoil with a recording gauge attached to the trigger guard with a Ransom Rest.
But felt recoil is another matter,as it varies from person to person.
You would have to use the same gun and ammo,with the only difference being the firing pin stop to really be scientific about it though.
Regards,Robert,
ga anamedpersonontheinternet machinist
(with apoligies to wild fillintheblank alaska))
 
At one time the Old Fuff conducted some experiments with a Colt equipped with a .22 conversion kit. The main problem with these kits was that the slide was too heavy for the little rimfire cartridge to move. There was a marked difference if the firing pin stop was fully radiused across the bottom, and it and the hammer face were highly polished. The intention here was to reduce the effect of the hammer (and its spring) acting as a brake, which is the opposite effect that you'd want on a service pistol firing ball loads or hotter.

While some may find a difference in felt recoil, that isn't and wasn't what I was interested in. Better reliability and less battering of the frame and slide was, and still is.

As a side note: Browning's earlier pistols, and the blow-back .25, .32 and .380 pocket pistols all have a small radius engagement in the slide where it contacts the hammer face. This feature that Tuner has pointed out was a standard procedure with Browning, and not limited to the 1911 design.
 
Stop

The feel of the recoil is all I am interested in. If it feels less,it must be less.
I didn't intend to test anything when I went to the range. I thought the Norinco recoiled less from earlier firings but had never shot the two of them together.
At this time ,I did shoot both of them together and proved to myself that the firing pin stop did make a difference.
I suggest that if you have any doubts,that you make your own tests.

I am happy with my results and do intend to put the same stops in all my 1911's :neener:
 
the rest of the story?

Just curious...does anyone know why the Army dictated the radius change to the original Browning firing pin stop design? Seems to me that the larger radius might improve reliability under battlefield conditions...might also increase service life by reducing forces on the hammer/pin...all at the expense of sight recovery and general shootability. I guess if one had to choose between reliability and about anything else under the most adverse conditions imaginable then reliability would win! For me, any improvement in shootability would be appreciated more, however, as a fairly heavy lead user I'd still be concerned about service life...if that's an issue here at all.

bullseyeboy
 
Why?

bullseyeboy asked:

>Just curious...does anyone know why the Army dictated the radius change to the original Browning firing pin stop design?<
*****************

It was done to make the gun easier to hand-cycle with the hammer down.
The biggest majority of the soldiers who were authorized to carry the pistol were restricted to Condition 3 carry...Magazine loaded, hammer down on an empty chamber...which required that the slide be cycled to ready the gun
for action. Some of the lads complained that it hard to do in a hurry, and
the Ordnance Department went back to the drawing board.

Rumor has it that several of the custom smiths who build the gun in 10mm
have found that the original radius on the stop allows the gun to be used with
18-20 pound recoil springs rather than the more common 22-24 pounders...
with no loss in frame protection. Seems like I also heard that the final recoil spring rate was determined by the mainspring rate. I may not correct on this point, but it does make sense.

There's also a "clew" there for the folks who lighten the mainspring load in order to lighten the trigger action...without compensating for the reduced
braking effect of the lighter mainspring. :uhoh:

Think about it... :scrutiny:
 
I agree with Tuner again. (I would have had the answer, but his keyboard is faster ... :scrutiny: )

The Army had experimented with Browning designed/Colt .38 automatics, and then a whole bunch of .45 prototypes. All were carried in full-flap holsters, and quick draws weren't on the program. Before a change was made on the firing pin stop some would draw the pistol (slowly), cock the hammer, and then cycle the slide. Of course someone complained, and the change followed.

It has been wisely said that when you change or modify something in this pistol at least two or three other parts and/or they're function will be affected. Unlike most handguns it was not designed - it was developed over a period of five years (twice that if you count the earlier .38 pistols) and as defects or problems were discovered they were corrected in the next prototypes. After the design was finalized in 1910 and adopted in 1911 few additional changes were made during the whole time it was used by the military services, and today's commercial guns are little different then the first guns except for cosmetics and materials.
 
It was done to make the gun easier to hand-cycle with the hammer down.
Click to expand...
BINGO!

Which is also the best way to test and prove the theorum.

Try it yourself and you will be able to FEEL the difference in the force needed to retract the slide with the hammer down.
 
Theory

BluesBear said:

Try it yourself and you will be able to FEEL the difference in the force needed to retract the slide with the hammer down.
*****************

Exactly so...and you'll notice that the extra resistance is at the very beginning of the cycle.

The mechanics are very simple. The slide isn't driven through its full travel...only during the first 1/10th inch of movement. There is a set level of energy produced when the gun fires...and that energy is established in the time during the first .100 or so inch of slide travel. Once established, only momentum completes the cycle.

The small-radiused stop...due to a lower point of contact and reduced leverage (mechanical advantage) against the hammer...causes more of that limited amount of energy to be used in moving the hammer, and it does most of that during the onset of hammer rotation...or in the first 1/10th inch of travel.

Since the hammer also has mass, its inertial resistance to movement is also
figured in...and like any other object...once motion is established, momentum
helps to keep it moving...BUT...the slide still has to work to start the process.
To simplify it...the slide has to work to accelerate it from a dead standstill, and some of the energy is dissipated in getting the hammer to move.
The more energy it takes to get the process started, the less momentum available to keep the slide moving...hence the reduced impact and felt recoil when the slide hits the stop surface in the frame.

Other factors must also be considered. Mainspring load...Hammer mass/weight...Even friction...but if all else is equal, the slide's speed and momentum will be reduced after the hammer is cocked.
 
Well, I bow out.

It seems I am heavily outnumbered by the "my subjective perception is reality" crowd.

Can't really argue with that. Nor do I want to.

Ya'll have fun now!!
 
Reduced Recoil?

I would say the reduced radius FP stop has the effect of slowing the slide down a "tad" due to the lack of mechanical advantage against the hammer and mainspring. This retards the shooter's impression of the whack that happens in a normal fitted out pistole when the slide hits the end of its travel. The whack is still there, it's just not as ABRUPT and it's partially taken up by the mainspring.

How'd I do, Tooner? :p
 
Sometimes the forest gets missed because of too many trees …

The original Browning-designed firing pin stop was intended to reduce battering between the slide and frame to insure greater longevity in the operational life of the pistol, and to better control the timing of the slide’s cycle to increase reliability. Tuner’s experiments and observations contained in an earlier post showed this is the case. (If plastic recoil spring buffers last substantially longer something is going on).

A side effect of using the small-radius firing pin stop is less felt recoil. This is subjective on the part of different individuals, but Ken is obviously sold. Others may or may not be, but it would seem likely that if the slide comes to a “softer stop†at the rear end of its travel the felt shock would be less. If one is using a pistol with a lighter slide (read that “sub-compactâ€) the effect might be more noticeable. In any case the mechanical principals are one thing, and subjective issues concerning felt recoil are another.

This thread has been, and continues to be especially valuable because it brings to light something that few 1911-pattern pistol owners know about, and for that we can thank both Ken and Tuner. One may, or may not decide to try a different firing pin stop, but for around $20.00 it offers an interesting option, and it is far more likely to be helpful then many other more expensive gadgets and gimmicks being sold as aftermarket accessories.
 
As part of my "Master Plan" (tm) for my Delta Elite my latest update has been going from the stock FP stop to the EGW peice, fitted, with NO radius. This was after going to a convetional 20 lbs recoil spring, a standard steel guide rod, and a 25# hammer spring to try to get the recoil impulse to be more comfortable.

I'm also intentionally leaving the heavy stock hammer in place in the hopes that it's extra mass will assist in extending the unlocking time as well. I can't find anyone who carries an extra heavy version. People seem to be obssessed with their lock times and cycle time when it comes to aftermarket hammers :)

Changing the slide stop made more of a differance to me than raising the hammer spring pressure 2 lbs and I can shoot the gun accuractly with noticably shorter split times.

However, I'm still getting an occasional FTExtract. Particularly with my full power 135 gr loads when the gun is dirty. Perhaps I need to look at the chamber condition and I know I still need to check the extractor tension. Every 25-50 rounds one will just stay in the chamber. But I'm not going to hijack this thread with my problems, I already know where to look to narrow them down :)
 
Many Posts

Black Snowman...Don't leave the corner sharp. If you want minimum leverage, just lightly break it on a narrow bevel. Your hammer will thank you.
*****************

Close BigG...but it's not a perception. It really does soften the blow.
*****************

Egg! We're not tryin' to shout ya down. We're tryin to eddy-cate ya. :cool:
While I completely agree that felt recoil is subjective and varies from one person to another, there is a provable, mechanical reason that the recoil is reduced. Why is it reality and not a subjective perception? Because a
mechanical change has been made that reduces the available force necessary to propel the slide to full travel. More force required to cock the hammer means less momentum remaining AFTER the hammer has been cocked.
Less momentum means that the slide is moving slower. Less slide speed means less impact energy when it hits the frame. Simple physics.

Let's try an imaginary experiment and see if it makes more sense.

Fact: The reduced mechanical advantage in cocking the hammer requires
more of the slide's momentum to perform that function. Simple machine...The closer to the fulcrum (the hammer pin) that you put the force (the recoil momentum transmitted via the slide) to the load (the hammer's mass and the mainspring's resistance to compression) the less total force is available to
complete the cycle once the extra resistance has been overcome.

You, plus a theoretical friend and a basketball decide to put it to the test.

Your friend holds the ball between his hands in front of him at arm's length with just enough force to keep the ball from falling.

You punch the ball with a hard right cross of say...200 pounds feet of energy...and knock it into his chest. Assuming that the ball's mass and inertial resistance and the friction imposed by his hands absorbed 10% of
the energy...the ball strikes his chest with some 180 pounds feet of force.

In part two, your friend holds the ball again, but this time he presses inward
on the sides of the ball with all the strength that he has. You punch the ball with a theoretically identical right cross...200 foot pounds again. The force
that your friend is exerting on the ball requires more of the available energy to dislodge from his hands and send into his chest, but the force of your punch is the same.

Everything remains the same except the frictional resistance to the ball's acceleration imposed by the force that he exerts on the ball. Agreed?

Your punch is the recoil impetus. The ball is the slide. His chest is the frame's impact surface. His hand pressure is the difference between the two FP stops, and is thus the only thing that changes the ball's resistance to acceleration.

In which experiment is your friend's chest going to take a harder impact from the ball? Do you think that it's only his perception of less impact when he tightens his grip on the ball...or is it reality? After the punch...Will the ball
move toward his chest at the same speed in each case..or will it be slower
when he grips the ball tighter?

Do you reasonably expect that the ball's impact against his chest would be the same in each scenario...or do you expect that it would be reduced with a tighter grip on the ball?

Standin' by...
 
Tuner --

You have missed my point completely (I think!). My point is that it will be impossible for a human being to be able to perceive the difference in forces you are discussing during the act of firing a 1911 .45 acp pistol. Any one that claims to be able to do so is, in my opinion, deluding themselves. I have suggested a method to prove this one way or another.

However, OF COURSE changes in the design or specifications of things like the firing pin stop, and indeed any of the elements of the machine, will influence the operation of said machine in some way. I am not disputing that at all -- it would be silly to do so. I am focusing in on the fact that the changes you are discussing in this particular thread can't be detected by a human being -- they are too small for the human sensorium to sort out!!!!!!!

And with that, I really am out of here. The weekend is almost upon us, and I have some shootin' to do.


Oh, and by the way Tuner, it has been proven conclusively by better men than you, that I am uneducable. :neener:
 
Small Changes

the Egg insists that:

The changes you are discussing in this particular thread can't be detected by a human being -- they are too small for the human sensorium to sort
******************

Nope...they are detectable, and you don't have to go to the trouble if fitting a firing pin stop to feel it. Just get one 21-pound and one 25-pound mainspring and swap'em back and forth. Use a fresh shock buffer with each mainspring to begin the test and see which one shreds first.

The difference between the two stops is about the same as the difference between a 14 and an 18 pound recoil spring...or the two above mentioned mainsprings. It really is that much. I'll conduct the test...but it'll hafta wait for a better time. Got way too many pinto beans on my plate right now.

And...the only man that I ever met that couldn't be educated was my brother-in-law. :neener:
 
Human?

I don't guess that I am a human being. The first time I fired the Norinco after Tuner installed the stop,I noticed the difference in the recoil feel. I fired it several times afterwards and always felt the same.
This week when I fired it along with my Colt of the same size,I could really tell the difference in feel.
Same ammo,same size pistol,same springs and same day. I didn't mention the fact that a friend was with me and fired both as well and he had the same feel as I did.(maybe he is not human as well)
No matter who is right or wrong as long as I like the feeling that I get,I am happy :neener:
 
EGW Firing pin stop.

Egg, dunno about a double blind test, but I do know for certain that a small radius firing pin stop was part of the solution to correct some timing/reliability issues in a Colt Officers Model.

That isnt a subjective opinion. Before the EGW firing pin stop was installed, the pistola wasn't reliable. After installation of the EGW part, it is reliable.

salty.
 
I'll take your advice 'Tuner. I'm refinishing the gun tomarrow so I've got it all apart anyway. Only excuse I have is I can't seem to find what I did with my stones . . . [shuffles feet through piles of junk on the floor while looking about]
 
re:

Loose brick...aka Field Expedient Abrasive Tool...but if you're not too far from a hardware store, a sheet of 320-grit wet or dry paper on a piece of glass will do. Hold the corner on a 45 degree angle and pull it sideways across the paper evenly to break the corner straight across.
****************

Saltydog mah fren! Good to hear that little beastie is still doin' ya right.
The FP stop was just a small part of the timing puzzle. Believe it or not,
I've got another OM that's more stubborn than yours was! I finally squashed all the bugs on the 3rd try. :rolleyes: It's runnin' and ready to go home now. :cool:
*************

Ken buddy! You and your range pal ain't the only ones to notice that little side benefit. I did one up for a guy a while back without tellin' him about it,
since I had to fit an oversized stop to keep the extractor from clockin', I figured..."Why not"? When he called me to report on the test-fire session, he remarked about how his new lot of ammo must be "weak", since the gun wasn't as bouncy as it was with the old lot. :D Sellier & Bellot hardball, I think it was.
 
Treat'em Right

Ken said:

Maybe if we sent a print-out of this thread to EGW, they would treat us right on prices for F.P. stops.
*********************

Yeah! Qualify for a 20% discount if ya tell'em...Toooona sentcha. :cool:

Money says that George is well aware that we're talkin' about his stops even as we speak. :p
 
Well, I am early to the party, but late to this thread. Not sure where I first picked up on the advantages of the EGW fps, but I am sure it was reading about different people's experiences with their Delta Elite's. Anyway, I ordered one, and had the good sense to follow Tuner's advice about breaking the edge. This was a used gun, but I estimate the mainspring to be about 25 pounds, definitely longer and stronger than stock. The previous owner's recoil spring was probably 28 pounds! Way too much!

Sidebar; Tuner, have you ever seen a change in recoil spring cause a change in point of impact? Like 4" at 25 yards?

To make a long story short, minor modifications will probably cause less problems than major modifications. The combination of a slightly heavier mainspring, a slightly heavier recoil spring, and a slightly less radiused firing pin stop all add up to a 10mm which shoots much better. If Colt had done this the first time around, I bet that the Delta Elite would still be in production. Of course, that tungsten recoil spring plug is just icing on the cake.

Yes, it is hard to rack the slide with the hammer down. No problem, simply cock the hammer first. ;)
 
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