View Full Version : AD from M1911A1 Series 70 dropped on muzzle.

April 21, 2001, 10:04 PM
I am involved in a very detailed and extended discussion on the subject that Series 70 Colts and other like M1911A1s are not as safe as Series 80 Colts because of no "firing pin lock". The other side has gone as far as saying that current Springfield Armory handguns have a "safety concern". I am of the opinion that there is no AD firing pin drop problem with any Series 70 type M1911A1 pistols, as long as they are maintained with quality servicable parts. And especially none with the Springfield Armory handguns. I can not find any source / reference material that covers any drop testing of the weapons, any ideas? I do need some help in showing that the other side is full of mud.

April 21, 2001, 10:16 PM
I can't remember the name of the study, but this has been examined. It's possible, though highly unlikely, to cause the series 70 pistols to AD (or ND) if you drop them just right from a sufficient height.

Joe Gulish
April 22, 2001, 12:14 AM
You might try looking at http://www.1911.com or
http://www.sightm1911.com. Their is a link on The
Firing Line link page for the second one.

Both have a lot of info on 1911's.

Jim V
April 22, 2001, 05:23 AM
IIRC, the US Navy studied the question and found a drop of about 15 feet was required to have the pistol fire with a muzzle down drop.

James K
April 22, 2001, 06:24 PM
Hi, Clem,

Sorry to contradict you, but the 1911 type pistol does have a safety problem in that if dropped on the muzzle, there is enough firing pin creep to set off a chambered round. Whether the gun is cocked or not is irrelevant, as hammer fall is not involved. This is the problem that Colt addressed in the Series 80 and as other makers have also done.

As for tests, take a look at the NIJ report at this address:


That having been said, the cases of that type of AD happening are rare indeed. The pistol has to drop at just the right angle, at enough distance, etc. Most accidental discharges are due to user stupidity, not a failure of the gun or gun design.


April 22, 2001, 07:14 PM
While you can get an AD in rare instances by dropping a series 70 1911 on the muzzle, it's not likely. AFAIK, only Colt and ParaOrdnance have the series-80 firing pin block. I don't lose any sleep over my 1911 firing if I drop it, my Garands and AR-15's also suffer from the same "problem". :D

April 22, 2001, 08:44 PM

Have to ask, just downloaded that file and actually READ it, the only gun that "fired" when dropped was a Sig 229. All 1911 pattern guns tested (Colt and Kimber) passed. The Colt was a Series 80, but the Kimber does NOT have the Series 80 style safety.

April 22, 2001, 09:43 PM
Jim & others, thanks for the info and source material. Now, if anyone knows of any reference to the FBI testing and accepting the Springfield M1911A1 for their SWAT & HNT agents, that would help.
I feel that if you put a Heavy Duty firing pin spring and a titanium firing pin in a series 70 Colt, you should be okay because titanium weights 62% of a like item made of steel. I have titanium in my Colts and the firing pin weight feels like it's a tooth pick.
Anyway, thanks again.

April 23, 2001, 03:24 PM
The sheer mass of the M1 makes muzzle-down discharge quite unlikely. Most surfaces, even concrete, will "give" a little when smacked by the muzzle, decreasing the relative decelleration of the gun/cartridge and the unrestrained firing pin.

A to-pound pistol is another matter. The M1911 drop-fire "feature" is quite rare, but I have read at least three firsthand accounts of such events, and references to maybe five more. Hearsay to you, but I believe it. The physics is sound, but don't ask me to run the calculations!

April 23, 2001, 04:59 PM
The DOJ piece reports passive firing pin safeties on the Kimbers.

Note: The thick rubber mat makes it an "easy" test. They should repeat it using that fake-wood laminate flooring. It's essentially 5/16-inch tempered Masonite or particle board (depending on maker), over a 3/32" foam piece.

Much more likely to "jar off" a sear. Much more realisic test. How many dropped guns DON't happen on carpet?!?!?!

April 23, 2001, 06:28 PM
Interesting, thought these were production guns. The test was done in 2000. Kimber has just now started listing ONE model with a passive firing pin safety, and it isn't one of the ones tested. I KNOW that my Ultra CDP doesn't have one. That still leaves the question, the poster put this article up as "proof" that the 1911 has this problem, and the only gun listed that "fired" isn't a 1911 pattern gun. Whether the ones tested have firing pin safeties or not, what was the point of the posting of this article. As for the original question, yes, it can happen, IF all things happen just right (or wrong - depending on your point of view). The gun has to drop far enough, land on a hard surface squarely on the muzzle, etc. Since most 1911 pattern guns tend to be butt heavy (when fully loaded at least) I find it unlikely that they would fall far enough and then land squarely on the muzzle. Certainly not going to worry about it myself (and neither of my 1911 guns has the firing pin safety).

April 24, 2001, 06:49 PM
Cheapo, we'll have to agree to disagree about all the other military guns that don't have any firing pin lock. I don't know about the concrete around your way, but around here it doesn't give much from a 2 pound gun or a 10 pound gun! How about my 5 pound M1 Carbine? Or, perhaps the 6 pound AR? I also have a problem with all those AD's from dropped 1911's that you claim. If I knew that many clumsy people, I'd move. :D

As far as firing pin safety's on Kimbers, I own one and have looked at lots of different models, and I've yet to see one with a firing pin safety. There may a gun equipped with one in their product line, but it's sure not a common feature of most of their guns.

April 29, 2001, 12:03 PM
Kimber's 2001 catalog describes how their models will be phased in with the 'series' II modification. It uses the compression of the grip safety to disengage the firing-pin safety plunger. Therefore, this design will not hinder a really good trigger pull as it can in the Colt's.

IIRC, the old Army testing showed that the 1911 must be dropped from a height of 21' feet onto a hard surface to generate enough inertia for discharge. But, what if your firing pin is slightly overlength? Or, your firing pin spring is old/weak. What if this is present in a gun with a tuned target trigger, with a minimum of sear/hammer engagement? Hmmmmm, that changes things a bit, yes?:D

A Muzzle down discharge doesn't seem to be much of a concern. Afterall, isn't that a relatively safe direction for the bullet? Unless, of course, you are on other than the bottom floor or deck of a ship.:o What if it were to land on the tang of the grip safety, with the muzzle UP?

April 29, 2001, 01:45 PM
Attaching a firing pin block to the grip safety would seem to remove 1911 compatibility for a bunch of parts... I'm not sure I'd be that eager to buy a Kimber if they do that to them...

May 3, 2001, 04:46 PM
Johnwill, I said that I've READ firsthand accounts. Never been there for one. Don't plan to.

I really like the idea of linking the firing pin safety to the grip safety. The only disadvantage, which really doesn't apply to the M1911 unless you're silly enough to want to carry it chamber loaded, hammer down, is that you must release your grip safety while lowering the hammer in order to get the safety margin afforded by letting off the trigger after releasing the hammer (as on a Series 80 Colt or any modern revolver).

As I understand the physics, the "give" and compression/flex of and friction between the many parts between the muzzle and the firing pin, as well as possible deformation of the muzzle's metal and crunching of the concrete, will ALL combine to absorb some of the impact energy and make less firing pin energy available to set off a chambered rifle round.

But I do agree that a muzzle-down rifle with floating firing pin (or even with a return spring like some AKs) WILL go bang if dropped from a sufficient distance. Anyone know how far of a drop it takes?

Read the DOJ report where it describes the rubber mat. ONE INCH??? Hardly realistic.

May 4, 2001, 01:20 PM
I recently replaced a barrel in a 1911, (I believe it was an 80 Series). The owner claimed that he'd dropped the pistol on his concrete garage floor and that the pistol went off. The end of the barrel was bulged so much that I had to cut the barrel off to remove the bushing.

I didn't really believe the story, but don't have any other theories as to how the barrel was bulged. There's a possibility that it's a 70 Series. It was a nickled Government Model, whatever it was.

May 4, 2001, 03:51 PM

Talking two different types of AD here. The original reference was to the inertial firing pin going far enough forward under impact to fire a chambered cartridge. Action had nothing to do with anything. You are talking the hammer falling off the sear. Assuming proper maintenance and fitting (no home gun smiths please), a working grip safety, a working thumb safety, and proper half cock notches the second should never happen. If it does someone has butchered up the insides of the gun in more than one area.

James K
May 4, 2001, 09:20 PM
Hi, SW627pc and guys,

Sorry for the misunderstanding. I cited that NJ study because they did the drop test and one gun failed, not because most guns passed. The situation, as I noted, is rare, but it can happen. My 1911 type pistols are all pre-Series 80 and I don't worry about what happens if I drop one because I don't go around dropping my guns. As I said, most AD's are due to human error, not to any deficiency in the gun.

The idea of having the firing pin block operated by the grip safety is an old one, patented in 1937 by William L. Swartz. Colt made it standard on commercial Colts of that period, but dropped it during the war as it was not required on military production. After the war, they chose not to revive the idea and used a different design in the Series 80. The Swartz safety has been removed from many of the guns that originally had it, but a round hole beside the disconnector on the top of the frame and a corresponding hole in the slide show where it was. It does not affect the trigger pull and the shooter does not even know it is there.


May 4, 2001, 11:17 PM
I find it interesting that the barrel was "bulged". Was it bulged right at the muzzle? Don't you think the round leaving the barrel would kick the pistol muzzle off the deck? I've seen bulged barrels in my Marine Corps armorer days and they were mostly caused by, 1. another round in the barrel that was stuck (squib load), 2. oil or other fluid in the barrel (hydrostatic compression), or 3. something else in the barrel (patch, bug, mud). Now I know, anything can happen and I know we all have seen some strange stuff, but................? Oh well.

John Lawson
May 5, 2001, 02:51 PM
First, an "accidental discharge is caused by a part failing and the weapon firing, such as happens with a loaded and locked Luger when the projections on the firing pin shear from fatigue and the gun discharges. "Unintentional Discharges are caused by human error.
I have made personal drop tests, with a mechanical engineer from two different heights. In 1,000 drops from the height of a Chevy Blazer, as would happen if your pistol fell to a hard surface as you got out only four drops resulted in a hit squarely on the muzzle. All four resulted in a faint primer dent.
1,000 drops from a tall ladder to a gravel driveway resulted in onoly one hit directly on the muzzle and another light firing pin dent in the primer. A slightly heavier firing pin spring would have negated the denting of primers.
FIguring it out using the law of physics, it requires a direct hit on the muzzle from five stories to cause ignition with a standard, (worn out) G.I. firing pin spring.
Mostly, air pressure will prevent the pistol falling muzzle first, and proper maintenance will take care of the rest.
All of the U.S. Services have carried 1911 pistols for most of the 20th century. To date, I have been unable to find a case history of a dropped pistol firing. Several who claimed this happened were proved to have been caused by other circumstances.
I know of only one authenticated case under very unusual circumstances, where a hunter threw a loaded, locked 1911 at a "rat" in the corner of a log cabin resulting in a fired shot. The pistol was mine, but the thrower was not yrs truly. The "rat" was a terrified little squirrel and the firing pin spring was installed in the pistol by the COlt factory in 1917; the incident happened in 1993. The pistol was thrown end over end, hit squarely on the HAMMER. Evidently, rebound from the firing pin stop was sufficient to propel the firing pin hard enough to ignite the round.
Since I was not present, I cannot vouch for the veracity of the facts, and I have no idea what role Jack Daniels played in this.
If I wanted to, I could perform a set of drop tests with the notion that "I'm gonna make this sonofagun fire" and probably get ignition, but all lyou have to do is drop your old .45 1000 times from 15 feet to see that the Navy test was flawed. ANy test, to be believable, must be duplicated at will with identical results. Try it yourself.

May 5, 2001, 03:16 PM
what would happen to a pre-80 1911 that was cocked and locked, loaded chamber of course, and dropped and discharged
what would happen to the safety?would the slide sheer it off?I think the gun would have some major damage if manual
safety was on when AD happened?

John Lawson
May 5, 2001, 04:05 PM
Interesting question, which I cannot answer, since I was not allowed to examine the pistol I mentioned. SInce I had offered it to my friend, he immediately paid up and it disappeared.
However, when I was about fifty years younger than I am today, I obtained a DWM 1918 pistol, which happened to be the only handgun I didn't have to sell to pay the rent and buy groceries. It was kept loaded and locked, with Winchester hardball in the magazine and chamber.
At about 3AM one morning there was a loud pop from the direction of the hall in the apartment house where I was living. After several of us searched without result, I retired to my kitchenette for a cup of tea and had a horrible thought. Oops! Guess what? The pistol was in the pocket of a leather WW-I aviation jacket hanging in my closet.
On taking the Luger apart, I noticed that the firing pin's sear notch had sheared off and the stub looked grainy. The fired case was still in the chamber and the safety lever was still in the up position. I did not note any damage to the safety bar. This was probably due tot he fact that the Luger is a true locked breech action that was actually a reduced version of the Maxim machine gun action. The pistol does not begin to unlock until the pressure in the chamber has dropped to zero. Although the safety bar stopped rearward unlocking motion, the heavy 40 pound recoil spring had absorbed enough momentum to prevent damage.
The 1911, being not a locked breech design, but a delayed blowback (there is still pressure against the case head when the pistol begins to unlock and part of the rearward motion is blowback) there would be collateral damage to some working parts, such as the thumb safety if the pistol fired loaded and locked. As I said, I have never heard of this happening...it was certainly not in any of our ordnance manuals, and they covered every possible serious malfunction and accident known at the time of publication.

James K
May 5, 2001, 09:16 PM
Hi, John,

With all due respect, the Model 1911 is not a delayed blowback. It is, like the Luger, a recoil operated pistol. Gas pressure has nothing to do with it except to move the bullet. If the barrel of a 1911 (or a Luger) is completely blocked so the bullet cannot move, the slide will not move and the gun will not open.

As to what happens if the 1911 is fired with the safety lock in the upward position, the safety lock is strong enough (as it was in the Luger) to prevent slide motion.

I have not tried extensive drop tests, but have done enough experiments to know that that type of firing can happen. If you provide the guns, I will, of course, try to duplicate your testing and hopefully confirm your results.

As to the difference between accidental discharge and negligent discharge, you have a point, but you might be trying to change the world.


John Lawson
May 5, 2001, 10:32 PM
If you remove the extractor from a Luger and fire a shot, the case will remain in the chamber and you can pick it out with a fingernail.
If you remove the extractor from a 1911 and fire a shot, the case will extract from the chamber and jam in the feedway, due to blowback from residual pressure, but it won't remain in the chamber as in the Luger. Been there. Done that. Will do it again. Come visit. I'll demonstrate.
If you entirely plug the bore in either pistol and fire a shot, the barrel will burst at the point of greatest strain, the chamber, after it melts the primer into the firing pin hole and launches the firing pin backward with ferocious velocity. The Luger always fractures upward beginning at the extractor slot while the 1911 fractures sideways at the ejection port. Been there and done that also, twice each, though most certainly not on purpose.
And, no,not on my guns you don't.

James K
May 6, 2001, 10:18 PM
Hi, John,

I am not discussing a case where a blockage in the barrel stops a bullet after it has begun to move; that will certainly result in a burst or bulged barrel. I am talking about preventing ANY bullet movement.

In that case, what happens is just what I said - the slide never moves. The pressure escapes with a slight "pfft". Can the barrel contain the pressure? Of course. After all, the idea of a recoil operated locked breech pistol is to contain the pressure until the bullet leaves the barrel, else why put on locking lugs. It is the recoil from the bullet movement, not gas pressure itself, that operates the gun.


Mike P. Wagner
May 7, 2001, 10:50 AM
My CZ-52 (circa 1953) has a little plunger that drops down into a groove in the firing pin, and locks the firing pin in place. The plunger is pushed up by a little "finger" on the sear when the trigger is pulled. I guess it's to prevent ADs from muzzle first drops. Interestingly enough, the most popular firing pin replacement kit disables that safety to give a lighter trigger pull.

I sort of wonder if the designer had empirical evidence of a "dropped on muzzle" problem, was just being clever, or somehow derived from the design that this was necessary/advisable.

Mike P. Wagner

John Lawson
May 7, 2001, 07:22 PM
Well, I have no idea how you'd set that one up without blocking the barrel, but I'm willing to bet that the primer would become the projectile with a bit more than a pfffft sound as it set back into the firing pin hole, propelled the firing pin forcibly backward and compressing the spring to maximum, imparting a horrendous blow to the firing pin stop.
Do you have documentation on this pffft result? I have never seen this kind of test even proposed. I do know that if you ignite the primer, oxidizers in the powder will rapidly burn the powder. If there is no place for the presures to go, there is no way for a slow bleedoff to happen and escalating, they will usually make their own pathway.
I'm refering to the SEE effect of light powder charges in a rifle, specifically when I say that this could result in detonation, not burning. Every scientist I know denies the effect, but I know of shooters who were maimed or killed due to the result.
"Recoil Operated" is a broad generic term that has to be further defined before it has any meaning. Luger and 1911 actions are nothing like similar in how they work...Compare a 16" Luger barrel with the 16" 1911 barrel. Now, the dissimilarities become more apparent. The Luger functions as it always did,as a locked breech, while the 1911 displays distinct signs of being a delayed blowback.
If you ignite the propellant from outside the case with an arc welding torch or a direct application of heat you get considerably more than a pffft. Been there; Done that.

May 8, 2001, 01:55 PM

You're missing a few of each others' points. The M1911 is recoil OPERATED, although there are signs of some residual pressure at the moment of unlocking. The Luger is also recoil OPERATED, but has such a long dwell time* as those parts move around, that no pressure strong enough to dislodge the case remains when the unlocking begins.

*by this, I mean the TOTAL time between primer ignition and the unlocking movement. This includes the time that the barrel is moving backwards but unlocking for either gun has not yet begun.

Both the Luger and M1911 can be said to be recoil unlocked. Both undoubtedly get some measureable (but operationally insignificant) assistance in rearward motion from the gas-jet effect of powder gases escaping the muzzle after the bullet exits. And both might begin to move the barrel backwards more than .01 inch before the bullet leaves the barrel.

Air resistance? Your own example shows how unreliable that is. As anyone who has gigged for frogs knows, motion/spin imparted to a flying/dropping object can make it strike "just right/wrong."

I'll believe the tests when you have 5 or more impacts directly muzzle-down. On concrete. No pads. Even then, I'd rather see a statistics database of X height, primer ignition Y percentage.

If you want your ammo to be 100% reliable, would you also accept a .2% chance of the gun going off with a muzzle-down drop from four feet? 1% from 6 feet? 5% from 8 feet, as in the stairwell you climb every day? How light is the light primer strike, and what's the measured risk of getting a discharge?

May 8, 2001, 03:20 PM
I'm dumb for asking if thumb safety was on when 1911 was
droped and went off if the safety would be ruined or some gun damage, I bought a threaded barrel and the heavy fake supressor from Federal Arms Corp and the gun will not eject
if I fire the gun with the fake supressor hanging, the gun doesn't even open at all, and no pfft fart sound either?if
you lay the supressor on a rest the 1911 will rake and work as usual,should bought the aluminum fake thingy,they make some fair muzzle brakes too for the barrel.

May 13, 2001, 10:59 AM
Blowback-Found in automatic and semi-automatic guns where no mechanical locking system is used. When such a gun is fired, the weight of the hammer,slide and other mobile parts, as well as the recoil spring, combine to keep the action closed. Total weight of parts is greater than bullet weight,and projectile begins its travel before breech opens rearward due to residual pressure.(steindlers firearms dictionary).

Blowback Operation. Blowback operation (also called inertia action), in self loading weapons,uses spent case projection (cartridge case push-out) to force the bolt rearward, A primary characteristic of the weapons is the absence of any locking systems. Blowback operation may be divided into two types, which will be discussed in the paragraphs that follow.
(1) Straight Blowback. Straight Blowback weapons solely on the weight of the bolt plus spring tension to keep the breech closed until time of dangerous combustion chamber pressure passed and is most often found in low pressure ctg. weapons such as the M-3A1 submachinegun.
(2) Delayed Blowback. Delayed Blowback weapons have some sort of mechanical delay device by which the initial opening movement of the bolt is retarded slightly as the bolt overcomes the obstacle in its way. Examples of weapons using this type of operation are rifles and machineguns of foreign design since the US military insists on lock-breech high power weapons. (US Army definition from Ordnance manual verbatim)

Recoil Operation. This system uses the forward thrust (recoil) of the weapon to drive the barrel, bolt and other operating parts to the rear. The bolt is locked to the barrel and remains locked to the barrel until the bullet has left the muzzle and the gas pressure is reduced. After the bullet has left the muzzle, the bolt is unlocked from the barrel and continues to the rear. Various methods are used to unlock the bolt and actuate the other operating parts. The caliber .45 pistol has this type of operation.
(also verbatim from the same Army manaul as listed above)

I have seen example is .45s where with a broken extractor that the case sometimes stays in the chamber and sometimes does not. There are many factors involved in this: the rearward movement of the bbl.,case obturation and cooling of the case,tight/loose chamber,dirty vs clean chamber, & ammo pressure amongst other things can be the cause-not through blowback operation though.

I do not see where a M1911 meets any of the criteria for being a blowback weapon. It has a locked breech and does not seperate until the bullet has left the barrel.

This post is not meant to down any particular viewpoint but merely to illuminate operating systems.

May 14, 2001, 08:41 PM
Hi all, today I received a reply from Colt, it is as follows:

"Upon confirming with our Engineering Department, I was able to verify that we did not produce the model that you have in question. We did manufacture an M1911A1 during W.W.II, and in the 1970's we had the Series 70, however both pistols were never combined. I have also confirmed that we did not have any recalls or safety concerns on either firearm.
If you have any further questions, please feel free to contact me and I will assist you in any way that I can.
Maria Kilan
Customer Service"

My bust on the "model", I requested info on the M1911A1 Series 70. But, Colt appears to have not had any safety concerns about the pistol. So, the Series 80 was just to sell more pistols, I guess.