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

[HSMITH]

Jungle, racking the slide was a LOT harder, not a big deal though. Loads used were constant through all of my fiddling, a 180 JHP loaded long with a very fast powder. They chrono at 970 most days.....

Yes, it was a gun that I am very familiar with, that is why I hesitated to post what I saw and also question the validity of the results I had. I am curious as to what others have seen. I think I know what happened and what I saw, but I wouldn't put any money on it.

Tuner, I do pull the gun down out of recoil. I know I do, I have seen myself do it LOL. I can adjust from 40 to 45 to 9mm and so on very quickly, so I don't know how much emphasis to put on pulling the gun down out of recoil. Also, the type of shooting I am doing with this gun and the speed that I am doing it at isn't applicable to what most people are doing. The differences in time I am seeing are insignificant for most people too, a few hundredths of a second from shot to shot is all. Even the gun I am working with is not what most people are using, this is a fat 40, bull barrel, lightened slide, 1.5 pound trigger, yadda yadda yadda. It is a purpose built machine for playing gun games, and the shooting games are a whole 'nuther ballgame in many respects....

I did try a recoil spring change, I had a 12 in it and tried a 13, 10 and 11. Ended up liking the 11 and stuck with it for now, with the long radius stop. I could not tell much difference with the short radius stop in between the 10 and the 13, but I honestly didn't give it much of an effort. 20-25 rounds with each is all.

"Don't fix it if it isn't broken" is one of the unwritten rules concerning guns for competition it seems, and that is part of why I stopped testing different things. I don't want to sacrifice performance today, or tomorrow, unless I know paydirt lies ahead and I just didn't get a warm fuzzy about potential gains in performance. It certainly felt better, felt recoil is reduced by a large amount, so I was surprised to see the timer tell me I was slower. It felt like it HAD to be faster, especially with how much more stable the gun appeared to be in firing.

At any rate, I like talking about guns and can't help but fiddle with them....

 

[jungle]

Tuner, Thanks again for the friendly offer. I will try one as soon as the pipeline fills back up, and can do the fitting myself with no problem.

One has to wonder why the major makers, semi-custom, and custom smiths haven't adopted this across the board. The concept has been around for quite awhile, they are aware of it-even to the point of using it in a few exceptional cases. So what is the downside? More difficult manual operation of the slide, possibly more sensitivity to the odd light load, and of course the need to bring the mainspring up to 23 lbs and the recoil spring down to 14 lbs to recieve the full benefit. No sweat, plenty of springs around.

Don't fix it if it ain't broken is a written rule for defensive weapons, but in this case there is enough curiosity to try it on the range.

 

[Old Fuff]

So which is it?

The Old Fuff suspects a bit of both. Clawson usually goes into great detail concerning changes, but on this one he simply mentioned it in passing. I too have read about complaints from the horse-troopers, but I'm still trying to find it.

The importance of the cite I posted is that Colt (and obviously the Army) knew that there was a relationship between the firing pin stop radius and slide velocity - at least in 1918.

There is no question that the 1911 platform (excluding sub-compacts) will work regardless of the firing pin stop radius - at least within reason. The advantages of the smaller radius come into play when, for whatever reason, you want to slow slide velocity without going to the ineffective use of heavier recoil springs.

 

[1911Tuner]

Custom Smiths

Jungle pondered:

>One has to wonder why the major makers, semi-custom, and custom smiths haven't adopted this across the board.<
**************

Many of them (Custom builders) have...but most use it on the 10mm pistols so they can drop recoil spring loads without sacrificing the buffering effect when the slide smacks the frame. Heavy recoil springs help buffer the impact stresses in recoil, but make'em worse when the slide goes back to battery. Slidestop cross pin holes in the frames get wallowed out and elongated...Frames crack adjacent to the crosspin hole...Lower lug feet take a pounding, etc. No such thing as a free lunch. Slides have been known to crack at the junction of the spring tunnel, where a sharp corner causes a stress riser. If the small radius reduces impact by 10 or 15%, that equates to either a 10 or 15% smaller chance of a crack or failure...or it extends the service life of the slide by a like amount. Equate it with reducing your powder charges by 10% and it starts to make sense.
(Upping the recoil spring load/rate also makes magazine timing and function more critical because of higher return to battery speeds.)

Again...Buffering impact is the real reasoning behind it. That it also changes the recoil charactistics of the gun is a side-effect, and since no two people grip the gun exactly the same, the resulting "feel" will vary from shooter to shooter.

 

[jungle]

So they have come to the conclusion it is neither needed or desirable on 1911s that are not 10mm, or other higher than .45 ACP energy rounds?

Shockbuffs seem to be a more widely used remedy to decreasing the slide to frame impact, and I notice you use them on your range guns.

 

[1911Tuner]

>>So they have come to the conclusion it is neither needed or desirable on 1911s that are not 10mm, or other higher than .45 ACP energy rounds?<<

No. I never implied that. You jumped to a conclusion. Some use'em on .45s too. One local smith will use nothing but...even on 9mm pistols.
******************

>>Shockbuffs seem to be a more widely used remedy to decreasing the slide to frame impact, and I notice you use them on your range guns.<<

Nope. I never use shock buffs, and never have very much...beyond curiousity when they first emerged. I used buffs to see if there was any difference in the life of the buffs between the standard stop and the small radius stop. There was. I drew the conclusion that the slide doesn't hit the frame as hard with the small radius stop.

For what it's worth, I think that the shock buff is a solution to a non-issue.
Either that, or an ingenious marketing ploy for the man who invented'em and then convinced some of us that we were destroying our guns without'em.
A little like the Para PXT extractor, the full-length guide rod, and the Tripp Cobra magazine that corrects the "flawed" feed angle. Oh, how DID we ever manage without such things?

PS

None of my long-term/hard-use beaters suffer any slide or frame impact damage...and two of'em have collectively passed the quarter-million round mark. Back in the days before George Smith introduced his tuneable, square-bottomed stops...when I couldn't find any originals, I made my own. I drink a
toast to ol' George every time I need a few. Instead of takin' hours to make'em up, I just pick up the phone and the mailman brings'em.

George...SALUTE!

 

[Old Fuff]

So they have come to the conclusion it is neither needed or desirable on 1911s that are not 10mm, or other higher than .45 ACP energy rounds?

I'm not sure that too many of our current cop of clone builders and custom smiths know anything about the firing pin stop effect - and care less if they do. Considering the reliability problems that seem rampent in some of their products it would seem that they aren't too knowledgeable about some other things either.

Shockbuffs seem to be a more widely used remedy to decreasing the slide to frame impact, and I notice you use them on your range guns.

Again, relatively few .45/1911 owners outside of this forum are aware that they can control slide velocity to a degree with the firing pin stop. The conventional wisdom is to use plastic buffers, sometimes in combination with stronger recoil springs. As for myself I don't want to buffer the slide at the end of its stroke, when it needs a kick in the butt for reliable feeding. What I do wnat is to slow the slide at the beginning of the rearward cycle. I also don't want to batter the slide stop pin when the slide goes into battery with an over-loaded recoil spring.

Last but not least - over the long hall the firing pin stop will last and be more economical then changing expendable plastic buffers.

 

[jungle]

Don't have any use for buffers, but as Tuner pointed out, they can give a rough guide to slide velocity at frame impact when trying different combinations of springs.
Can't really say what the custom builders are thinking, but it was a question not a conclusion.
Don't worry Tuner, you won't have to roll your eyes skyward anymore, I will try it and report back. Well, maybe you will have to roll them skyward again.

Ya'll have a good one, enjoyed it.

 

[1911Tuner]

re:

Lordy! Let's put this one to rest...Please!

Sorry Jungle. ya gotta admit though...It's a little wearisome havin' to say the same thing over and over again.

When ya try it out...be sure to use a fresh recoil and mainspring. It's a system. Always has been...even with the 7/32nds radius.

 

[jungle]

Tuner, I understood what you were saying before you said it. Repetition and counting of cadence was not required. Results have been mixed when reviewed by some VERY experienced shooters, but of course I have faith in your experience. Enjoyed the conversation, as always.

 

[BluesBear]

You can't shine light through a closed door.







and





You can't teach anything to a person who already knows all.

 

[medmo]

Okay I have had enough.... I have been following this thread from the get go. It is simply the coefficient of friction related to surface bearing. Please, I beg you, don't make me do the math. This trick was shown to me around 1983 in a class at Yavapai College in Prescott Arizona from a guy who was a retired USAF armorer. He was the guy that built the guns for the USAF shooting team and what a gold mine I found when picking his brain. God rest John's soul. John was a genius with the 1911 and if God competes with a 1911 in "Divine Shooting Matches" I know who works on his guns. If something is real then it can be proven with math. This can be proven with math and friction coefficients.

Okay layman terms:

You know that one part of the freeway that you really dig driving on because it has sharp turns and it's kind of fun? Now imagine doing it at the same speed with tires 1/8th of the current width and no tread. What happens? You slide off the road missing the turn. That is it in general terms. In order to calculate it specifically you would have to measure or guesstimate Ra on the contact surfaces, measure bearing surface area and throw quite a few Greek alpahbetic characters in a formula to measure and compare the actual forces. Not fun but certainly do-able.

 

[jungle]

medmo, That is some math I'd very much like to see, but I can understand your reluctance to share it.

 

[1911Tuner]

Re: Ra

Medmo...Not bein' an advanced mathematician, I can't dispute it...but it's got more to do with simple leverage than friction. The smaller radius lowers the contact point on the hammer, and moves the force (slide) closer to the fulcrum. (hammer pin) While that'll probably increase the frictional resistance during the hammer's rotation, it's not the primary mechanism in delaying the slide.

Get on a see-saw with a small child. When the fulcrum is in the center, the little'un remains in the air. Move the board to get the fulcrum close enough to you, and the wee one can keep YOU airborne. Leverage.

And...This one's probably best laid to rest. Fatigue is starting to push a few of us some toward a flamefest...and that ain't good. One day, I hope to have Jungle and some others over for a range trip/turbocoffee/BS session and if we get all gnarly over somethin' like this, it'll never happen. I've made a few lasting friends through these forums, and hope to continue the tradition.

And with that...

Goodnight Chesty..wherever you are!