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

[Shootcraps]

I did it!

Finally had time to sit down and try this out. Removed the fps from my Springfield V10 Ultra and started fitting the new one. I noticed that the original fps was strongly beveled. Compared the two so I wouldn't screw things up too much.

The main point was its width. Trimmed some off the left side and it finally slid all the way into place, with the firing pin hole lining up just right. Then I had to raise the shoulder a bit to clear the ejector. Broke the bottom edge to give it just a bit of bevel and things looked pretty good.

Took it to the range this morning. Boy, there seems to be a noticeable difference! For such a small gun, it barely moves. I know the ports help, but don't remember it being so smooth. Ran a few magazines through it, stopping after each to check for unusual wear and found none. After a bit I noticed two, equal marks on the hammer below the marks from the original fps. Looks like it's hitting nice and even. I"ll have to try it some more next weekend. If that looks good........

then my other 1911s may be getting new stops.

 

[1911Tuner]

Another Unrehearsed Testimony!

Excellent news there Crapshooter!

Have ya noticed any difference in your ejection patterns? The first thing that many people notice is that the brass hits the ground from 25 to 50%
closer to the gun than with the bad old stop...

Now...Ya wanna really feel "smooth"? Drop your recoil spring down 2 pounds and try it. Except for the extreme-duty beaters, I use 14 pound springs in all my 5-inch guns. Smoooooooooth!

 

[Shootcraps]

Thanks Tuner. I was at an indoor lane and the empties were bouncing off the side wall, so I don't know where they would have landed.

I'll order a 22 pound spring from Wolffs and see how it works.

 

[UberPhLuBB]

Just thought I'd let you guys know that you cleaned Brownell's out of their stops and the entire new batch they got in (81 pieces as of 6/3/05, Brownell's said their order came in May 28th) are all cut for 70- AND 80-series 1911's. If you have a 70-series, you should go directly to EGW to get one, either they sent the wrong ones to Brownell's or Brownell's ordered the wrong ones. They're ugly as sin on a 70-series.

Also, the picture at the Brownell's site is misleading on the -001 part. The image looks like untreated steel but they come blued or with a black oxide finish (actually I think the -058's have a black oxide finish).

I'm sending my FPS straight to EGW to have it exchanged with a 70-series stop. After George sees the Brownell's tag on the bag he says he'll try to straighten it out with them.

 

[1911Tuner]

Stops

I just ordered 6 S-70 type stops directly from George. They were a little rough around the edges...looked to me like a dull end mill was to blame, but a few licks with a smooth mill file cleaned'em up slick as a button. Haven't done anything else except cut the radius and put'em back in the drawer
to await assignment.

I sent one to a guy on another forum to fit to his chopped pistol, and he reports that it's like shootin' a different gun. Smooth cycle...Brass falls in a neat pile...Less muzzle flip and gets back on target quicker...An altogether worthwhile tweak, sez he...and he's gonna put one in all his pistols.

 

[ken grant]

Firing pin stop

Wish George would make some stops in Stainless Steel for Series 80's. Sure could use some for my Colts

 

[George Smith]

Ken

If the Sig GSR line starts up again in July or Aug. We can make some SS EGW OS Stops using the same materials. We will have to wait and see if a new PO is forthcoming.

Thank you all for the great post,
and thank you for the work

geo

 

[deker]

Wanted to say "thanks" for this thread

I spent a chunk of time today reading this thread and then took a look at the FPS on my Dan Wesson. It's WAAAY relieved and rounded (and consequently, I noticed today a tad loose and starting to slip down and drag on the frame on one side). I had switched to a stiffer recoil spring to calm my insane brass ejection, but I'm beginning to think that a properly fit FPS would do me more good and protect my frame from unnecessary battering in the long run.

So, George at EGW got my order today.

I wanted to take the opportunity to thank Tuner, Fuff, Riley, and everybody else for the info in this thread. This is honestly something I NEVER would have thought of with regard to my brass flying 15' to my right. For that matter, it might have been a while longer until I noticed the slightly loose fit of my FPS, but since this thread got me looking at it I noticed it while it was just a little rubbing rather than having actual damage to my frame.

thanks again for the great info folks,

-d

 

[Shootcraps]

You're welcome. We live to serve.

 

[Spartacus451]

Hi everyone, very interesting thread and modification. I will be trying it out as soon as I get the stop from EGW.

Would someone be so kind as to post a picture of an EGW stop with a radius that is appropriate for a 5-inch .45 shooting factory loads? I remember reading that the radius can be adjusted differently for every type of 1911s intended use and am not sure what would be most appropriate for me. I have some confidence in my filing skills and I am going to try and free hand it, and I need an image to compare my stop with so I know when I'm done.

***EDIT***
I saw the pictures earlier in the thread, but they don't give me quite enough to go on. If I could see a side view it would let me see the angles of the radius better.

 

[1911Tuner]

Picture

Most certainly. NYCMedic over on 1911.org did his first one about as well as I've ever seen one done freehand...so I swiped his picture for ya.

I use a slightly smaller radius for mine. This one is probably as close to the original .078 as you'll get it with a file and stone.

 

[Spartacus451]

Perfect, per Canuck-IL's advice I will try to track down some sandpaper to do it with for more control. That is a very small radius indeed. What is the purpose of the small radius vs. the square edge that comes from EGW? Does it give the firing pin stop less "bite" into the hammer making slide movement require more mechanical energy?

 

[steveracer]

The squared-off edge from EGW...

...will be sharp enough to wear on your hammer. If it's MIM, like my old SA Champion, it could clean the hammer right off with hot enough loads. I shot it about 100 times like this, and there was a definite mark in the hammer. I radiused it very slightly, and the wear ended there.

 

[jungle]

Slowing the slide. We have had a few discussions of the effect of recoil springs on slide recoil speed and also about hammer spring weights as an addition to this effect.
The conclusions were that slide mass has the greatest effect on the initial travel speed and that spring weight had little to do with initial slide speed. The higher the recoil spring weight outside the factory spec., the higher the felt recoil because the spring ties the slide to the frame and as weight goes higher it tends to absorb less and transfer more recoil to the frame. The recoil spring is much more a feeding spring than a major impact on initial slide movement although it does serve to slow the slide as it reaches the end of it's travel and the spring's force increases to rated weight.
A simple way to quantify the effect of a more sharply radiused slide stop would be to measure the difference in length from the hammer pivot point to the two points of hammer intersection between the two stops and then multiply that by the hammer spring rate, which will be far less than the rated weight at the point of initial movement. I would be surprised if it amounted to one tenth of an inch.
To get an idea of the forces involved measure the base of the .45 ACP case, compute area and multiply this times 20,000 PSI. The number will surprise you and this is the number we are working against with springs and mass. You will find that springs are a small factor when compared to mass in controlling the initial slide acceleration. Otherwise we could build pistols with very light slides and stronger springs and end up with lighter weapons. This hasn't proven to be the case.

 

[BluesBear]

As I have said before, a properly sprung 1911 pattern pistol will fire and eject just fine with NO recoil spring at all.

The fired case will land in the same area as they did with the recoil spring in place.
The cases will not be bulged.
There will not be a more prominent ejector mark.


I agree that the name should be changed from recoil spring to slide return spring.
Can we get a Constitutional Admendment?

 

[1911Tuner]

Calculations

Well...Here we go again. Rather than use bandwidth with calculations, I'll try to explain the "why" part of how this thing works like this.

Felt recoil in the autopistol is in three distinct phases. The three events occur so close together, that they seem to be one.

Phase one is the actual recoil...the "kick" of the cartridge firing. That one can only be reduced by changing ammo or...as jungle noted...by increasing or reducing slide mass. It is what it is.

Phase two is the effect of the recoil spring providing its own "Equal and Opposite" push between the moving slide and frame. The heavier the recoil spring, the harder it pushes the frame into the hand. The slide's velocity rearward also plays into the total effect. The faster the slide accelerates,
the more sharply the secondary effect of a given spring's loading will be felt.

Phase three comes from the slide impacting the frame at the end of its travel. The harder the slide hits the frame, the higher the gun flips
on impact. Hence, the less slide velocity that is available for that impact, the less the gun will flip. Also hence...the slower the slide accelerates with a given recoil spring, the lower the recoil spring's effect will be during the secondary recoil.

The smaller radius reduces the slide's mechanical advantage in overcoming the
mainspring, thereby delaying the slide's initial acceleration during phase one.
Think of it as tapping the brake at the instant that you nail the gas pedal in a drag race. The elapsed time at the end of the race will go up, while the terminal speed in the traps will drop. No matter how hard the car accelerates
after the brake is released, it can't make up for the lost time and momentum.
If two cars that are theoretically identical...the braked car will lose every time.

In the case of the modified firing pin stop, the effect on felt recoil comes mainly in the tertiary phase...reduced muzzle flip when the slide hits the frame. It seems to be one of those things that fit the category of the whole being greater than the sum of the parts. The only suggestion that I can make is to try it for yourself. The proof's in the puddin' so they say...and arguing the point further won't convince anyone of anything until they give it a whirl.

 

[BluesBear]

Tuner,

Wasn't the small radius the original design?
Didn't the large radius we see so much today originate with the Colt Gold Cup in order to get it to better digest the "softball" 185gr target wadcutter ammo?

The first big radius I ever recall seeing was on a .38 Special Gold Cup.
Up until then all I had seen was the old GI type.
I can't recall which my Father's first year Commander had.

 

[1911Tuner]

Radius

Howdy Bear,

The stop was changed by the Army Ordnance Department after receiving complaints from the cavalry that the gun was too difficult to hand-cycle with the hammer down...and it is harder to do...which will provide a clue as to its effect on the slide's initial acceleration. Once the hammer is slammed rearward, the effect ends.

 

[Spartacus451]

Otherwise we could build pistols with very light slides and stronger springs and end up with lighter weapons. This hasn't proven to be the case.

One thing that has always struck me is how light Glock is able to make the slides (I am making a big assumption that much of the weight is in the slide) on their guns and how light they make them in general. They seriously undercut even the polymer competition by 6 or more ounces for quite some time. The closest I have seen is the new S&W M&P which weight 24 oz with no magazine. The 17 is 22 ounces and the 26 is 19 ounces, and the 21 is 26 ounces. Do Glock slides weigh the same as everybody elses, say a 1911?

 

[Old Fuff]

Glock, like most other later automatics, use a cam on the barrel to control the dwell time - the time that the barrel and slide are locked together. By changing the cam surface dimensions the dwell time can be leghtened or shortened. Browning's link design works fine for its intended purpose, but one can't do much to adjust the dwell time, although some makers try by fooling around with the recoil spring. Within reason, if you can lengthen the dwell time you can lighten the mass of the slide. To my knowledge this was first done in the Browning Hi-Power in 1935.

 

[Walt Rauch]

I learn something everyday. thanks all.

 

[jungle]

It is interesting to examine the way factory engineers control slide speed with mass in the Browning style tilting barrel recoil operated pistols. Note the difference between the BHP in 9mm and .40. Heavier slide. H&K 9mm and .40. Heavier slide. Given identical guns within a group, one will almost always find that the engineering solution to controlling slide speed as bullet energy goes up is to increase slide mass. Colt chose not to do this with the Delta and ran into problems.
There is obviously a working range of weight and spring that is acceptable for a given energy. A 1911 in 9mm or .45 ACP will work with near identical springs, but the 9mm will have an easily felt slower slide movement. Colt's early solution was to introduce lightening cuts in the 9mm slide.Some people mistake the heavier spring in a heavier slide as a resistive effort at slide speed, but it is used to control the deceleration of a heavier or faster mass at the end of the recoil stroke.
If anyone has a Glock and 1911 and an accurate scale I think you will find the two slide weights very similar in .45 ACP caliber.

 

[Old Fuff]

jungle:

Part of this has to do with the fact that a larger cartridge (.45) usually requires a higher, and possibly wider slide because of the cartridge head size. But whatever weight advantage might be gained is lost if the slide is shortened to make a compact or sub-compact pistol unless other modifications are made to the shorter slides.

In his original link-based designs, Browning used the mainspring, hammer, and firing pin stop radius as an additional buffer on the slide. During the early 20th century it was not uncommon for individuals using the 1900 era .38 Colt's to cock the hammer before loading the first round into the chamber, and then lower the hammer on the chambered round. As Tuner noted, the Army didn't buy this for long with their new 1911 .45 pistols, but the design was good enough so that the pistol usually stood up to years of hard service.

During the development of the original Detonics pistol is was discovered that the slide - shortened by 2" from a Government Model - had a slide velocity that was increased by as much as 50%. But oher factors were at work besides lighter slide weight, including a shorter dwell time caused by the barrel dropping at a sharper angle.

 

[jungle]

Understood, but it is undeniable that modern designs use slide weight to control slide speed across the board. Compacts will be seen with thicker slide cross section than their full sized counterparts. The 1911 is a poor example of this, because the compacts keep the same cross section, but it is obvious that reliability suffers as slide speed increases due to lower mass.
In the case of Glocks, longer slides have lightening cuts to retain the same mass as standard sized slides. SIGs and H&Ks will be seen with thicker cross section through portions of the slide as the energy of the round is increased. Beretta quickly discovered reliability problems in previously very reliable pistols if slide mass was not increased in the move up from 9mm to .40. Rim diameter doesn't mean much, since almost any slide is wider than common rim diameters. Energy is the key and will have the most effect with respect to slide mass and velocity.

 

[Spartacus451]

I haven't gotten the part yet so I can't make any claims as to the efficacy of the modification, but maybe this thread is worth adding to the 1911 clinic.

As an FYI (don't know if it had been mentioned in this specific thread) but S&W 1911s require a series 80 firing pin stop.