1911 Slide closing on empty chamber

I cannot give you an exact speed number.
But, you can hear the hard metal to metal contact when you drop the slide on an empty chamber, and it doesn't sound good.

By design, slide velocity is slowed a good deal by the friction of stripping a round out of the magazine.
Without that friction slowing it down, the barrel lugs hits the slide a lot harder, the cams hit the slide stop pin a lot harder, and the hammer hooks to hit the sear a lot harder as the slide flies forward and slams to a stop.

When I was building National Match guns for Uncle Sam years ago, dropping the slide on an empty chamber might get you whacked up side the head with a bastard file by the nearest national match armorer.
It could undo hours of trigger work & slide fitting in no time flat.

I have to also think it had lots more to do with all the rattly loose & worn out GI issue 1911's then shooting them did.
It was common to drop the slide on an empty chamber at inspections, manual of arms drills, etc., and it most certainly was doing the guns more harm then good.

rc

The breach face should contact the barrel and rotate it until the lugs are engaged.

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The barrel of a 1911 doesn't rotate.
/Bryan

I think he meant the barrel link rotating and moving the barrel up or down into the lugs.

The round doesn't "bobble around" as it feeds. The 1911 operates on the controlled feed principle...or at least it does when all is in spec and proper magazines are used.

The slide isn't stopped by the breechface and barrel hood. It's stopped by the lower lug feet slamming into the slidestop pin. Remove the barrel and slip the slidestop through the link..then swing the pin and link to the in-battery position to see just what a small area of steel is bringing it all to a halt...then look at it closer...and then think about it a bit.

I think in some 1911's, the barrel "feet" don't contact the slide stop pin.

I know my Kimber deos big time. Huge barrel foot wear marks on the top of the SS pin. But my DW has no marks on top of the pin.

Better look again, Zero. Better yet, find an old barrel and remove the feet...just the curved part that the slidestop pin fits...then let'er slam to battery and watch the slide fly off the front of the frame.

I'm just going to say...rcmodel and 1911Tuner comment in the same thread. What a good day!

Yeppers!!

Lug wear on top of the pin indicates it is doing the lock-up on the pin, as a fitted match gun should.
But even on a sloppy loose link-locked GI gun, all that stops the slide from flying off is the barrel lugs hitting the back of the slide stop pin at full in-battery position.

Bottom line is, the name "Slide Stop Pin" has a double meaning!

rc

What I don't quite get yet, is how hammering on the barrel feet affects the sear and trigger group.

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It doesn't.

But the higher slide velocity slamming it shut empty without the trigger pulled allows the hammer hooks to smack the sear edge really hard.

When you shoot it, with the trigger pulled, the disconnecter prevents the trigger bouncing against the sear, partially or fully unseating it.
And it isn't hitting the hammer hooks nearly as hard either due to the lower slide velocity from magazine friction slowing it.

rc

:banghead:Nevermind, I found the marks. I was holding the SS lever upside down.:banghead:

One things for sure, I'll never have one of those beveled/recessed SS pin holes cut into my frame knowing this.

The problem with the sear isn't so much the faster slide dropping the hammer onto it, or the trigger bounce moving the sear part way out of the hooks. (The same dynamics are in play every time the trigger is pulled.)

The problem is the trigger's inertial bounce bumping the disconnect, which moves the sear just far enough for the sear to escape the hooks...and then get stopped by the half-cock notch. It damages the finely-honed sear crown if a match-grade trigger job has been done. Some aftermarket hammers have a modified half-cock notch that can only contact the sear in the center, where it has no effect on hook engagement. Holding the trigger keeps the disconnect out of the way. The trigger stirrup never actually touches the sear.

Many moons ago, when all the smiths had to work with were steel triggers, this was a real concern, and the standard wisdom of the day was to hold the trigger rearward whenever the slide was released to load the top round. It seems unsdafe, but in reality, this causes the sear and disconnect to function in exactly the same way as when the gun is fired.

It only becomes unsafe when the sequence gets mixed up and goes from:
"Pull trigger/Release slide" to "Release slide/Pull trigger" before the gun is pointed downrange.

Lightweight/low mass triggers have done a lot to eliminate this occurrence.

1st fraction of the travel at or near before the slide picks up a bullet to slow it down, the hammer has already been released fwd,

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No. The slide doesn't release the hammer to fall back to the sear until it uncovers the hammer. When the slide is on top of the hammer, it's actually holding it in an overcocked position. The hammer doesn't cock smoothly. It gets slammed back and rebounds off the grip safety tang and hits the slide.
If the hammer were to fall directly back to the sear, it would destroy the hooks and the sear crown quickly.

if the slide does NOT pick up a bullet it accelerates faster, hammering into the barrel feet harder.

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Correct...and the barrel lug foot isn't the only part that takes a pounding. Because the barrel foot stops against the slidestop crosspin, the holes in the frame also get whacked.
I've seen these holes egg-shaped and LW Commander frames crack in the bottom of the slidestop pin hole from people getting into the habit of letting the slide fly without ammunition to slow the slide down.

Another reason I'm glad I didn't buy an Aluminum framed 1911.

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It doesn;t do that if the gun isn't abused by getting into the habit of letting the slide slam to battery without feeding ammunition.

I still wonder how much slower the slide is, just dropping, vs bouncing off the aft stop (steel does bounce) and being propelled fwd during live fire.

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Quite a bit. Every little resistance that the slide encounters when feeding a round bleeds off speed and momentum. It's a cumulative effect.

Of course, when somebody installs an extra power recoil/action spring, it creates more forward slide speed and momentum...

Greg528iT said:

I'd like to see 4 different speed numbers. empty chamber chamber sling shotted, empty changer, sling shotted onto a bullet, and the slide bouncing off the slide stop pin after firing a standard 230gr, 850 fps round.

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That's only three different tests?

Empty chamber sling-shotted onto a bullet is the same as after firing a bullet. In both conditions, the slide starts from a stop, fully retracted with the recoil springs propelling it forward.

Empty chamber sling-shotted onto a bullet is the same as after firing a bullet. In both conditions, the slide starts from a stop, fully retracted with the recoil springs propelling it forward.

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Not exactly. When the gun is fired...assuming that a shock buffer isn't in the system...the slide smacks the impact abutment and rebounds. It gives the spring a little boost instead of having to accelerate the slide from a dead stop.

If we keep in mind that the term "Recoil Spring" is a little misleading, we can start to understand it. It's technically an action spring...just like the ones in your M1 and M14 rifles. Its primary function is feeding the next round and placing the weapon in battery. That it does decelerate the slide and buffer slide to frame impact is incidental, and a necessary function of being compressed in order to perform its real job.

Neither does it have anything to do with unlock timing nor containing pressure, and very little to do with slide delay. Ned Christiansen proved it by removing the recoil spring from a 10mm pistol and firing it repeatedly with full power ammunition. There was no damage and no indication of early unlocking. When reassembled, the gun functioned just fine.

To address the speed question, the entire sequence...recoil and return to battery...has been measured at approximately 20 fps during live fire. If we assume that the slide will be much faster going backward than forward...we're not talking about a lot of velocity on the return trip while the gun is feeding normally, and if we measure it starting from the point that it starts to encounter resistance from the cartridge...we may be talking about no more than about 3 fps.

Greg528iT- I know where most of your questions come from in another thread, And all i can say is most of what i said is stuff ive learned from reading 1911Tuners posts and my own experiences.
His experience is about the size of the Earth and mine is about the size of a baseball in comparison when dealing with 1911's. That doesn't go for just here, But gun forums across the net he helps educate people on. He may not be God, But he sure knows his 1911's and i take his word as 99.3% gospel when i read it.

rcmodel- For some reason i seem to have not recognized your name like i have with Tuners so forgive me for not giving your wisdom credit when due.

Tuner, if you could would you mind reading and responding to what you think in this thread?
http://www.thehighroad.org/showthread.php?t=584483
Its basically what started this thread, But id like to see your answers to know if im giving bad advice more than anything. If im giving good advice its mainly from what ive learned from you that taught me while i did my own 1911 trigger jobs.

I cant add much here as 1911Tuner has pretty much covered all the bases and i can only make things confusing or wrong as i don't explain things as clearly as he does as my mental thoughts don't make it to the keyboard from my brain like it does for him.

If not for Tuner id most likely still be letting empty slides slam home of freshly done trigger jobs and then judging the work as bad if the hammer was to follow with no round in the mag.

One question id like to ask is this. From my experience ive done a couple trigger jobs and started testing the work with an empty slide slamming home and the hammer would go to half cock. When a snap cap or live round was added if i was safely at the range the hammer follow would stop. After a few hundred rounds threw the gun flawlessly id take the gun home and clean it without disassembly and then retest it with no snap cap and the hammer follow would no longer happen on the empty slide.
Is this from the action wearing in and settling into place and that can stop a gun from having hammer follow on an empty slide that had it prior to being shot?

Now i know a slight adjustment on the sear spring can many times fix hammer follow IF the trigger job was done correctly. But when dealing with someone who cant adjust his spring due to lack of experience what are the odds of the issue going away if the only complaint was hammer follow on an empty slide/mag?
Of course once safe testing with snap caps was performed first and then with live fire testing with 1 round in the mag at a time and then moving on too two rounds in the mag to keep full auto issues from occurring if no firing pin safety is installed on the gun?

Cliff notes:

-Bad for slide stop pin. Barrel foot hits it much harder.

-Bad for the frames slide stop pin hole. Slide stop pin hits frame harder. May oval out Aluminum frames.

-Bad for Sear. The sears finely honed surface hits the hammer harder.

-Bad for Sear. Hard slam of the slide onto the frame can bounce the Sear over the first hammer notch on onto the secondary notch. The 2nd hammer notch isn't too good of a thing to have your sears surface hitting. (some 1911's won't have this problem)


About right? Let me know, I'll edit that out.

I'm still curious as to what the speed differential is. Just to know the numbers.

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Beyond the 20 fps measurement for the entire cycle, I don't know if they're available...or where.

Anyway...It's a mechanical fact that steel on steel impact causes deformation of the steel. It's a physical fact that the faster an object is moving when it impacts, the more damage is done. So, given those two undeniable mechanical and phgysical facts...there's just no good reason to let the slide slam when the gun is empty. You don't slam your car door. You don't slam the doors in your house. Why abuse the pistol just because ya can?

May oval out Aluminum frames.

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Seen some steel frames with wallowed holes, too.

Ever seen people at a shop or at the range excessive rack their slide with and empty chamber and then let it slam home....

I have seen it more than once and shops which is why I never buy the gun in the case if I can help it. LOL