Can we show Revolver's are not as reliable as today's Semi-Autos

Good Fortune

Awhile back I did this analysis:

Revolver vs Semi-Automatic Handgun Reliability Using FMECA Approach


Summary of Results:

Modern handguns are extremely reliable. They are capable of firing many thousands of rounds with no malfunctions. In evaluating the difference in reliability between revolvers and semi-automatic handguns, the primary difference is the dependence of the gun on external factors such as user, ammo, and magazine (if a semi-automatic).
The user's ability to properly manipulate and hold a semi-automatic is a key to semi-automatic reliability. Revolvers have less dependency upon the user than semi-automatics.

After the gun user, a gun system is most dependent upon the ammunition. Since ammunition is used once and an individual bullet can't be tested without "consuming" it, it is not possible to know with absolute certainty if a specific bullet will perform properly in a gun before using it.

Semi-automatics are more dependent than revolvers upon properly functioning ammunition since the stripping the bullet from the magazine, inserting the round into the chamber, discharge of the round, extraction of the used round, ejection of the used round, movement of the slide rearward due to ammunition discharge has significant dependences on the ammunition for properly functionality.

Semi-autos also require that magazines function properly for the gun to operate properly.

Semi-automatics have higher "first shot" reliability assuming a round has been properly inserted in the chamber.

Revolvers generally have slightly higher accuracy repeatability due to the barrel and sights being mechanically fixed.

Semi-automatics are generally less susceptible to fouling due to gun powder residue than revolvers. Hence semi-automatics generally do not need to be cleaned as often.

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System Description:
The handgun system consists of the following components:
-Gun
-Ammunition
-Magazine for semi-automatics
-User

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Assumptions:
1) The gun is being maintained properly. Proper cleaning, lubrication, tightening of screws, and replacement of parts that wear (like recoil springs) are performed at recommended intervals.
2) Proper ammunition is being used.
3) The magazines used in semi-automatics are compatible with the gun.
4) The gun has been "broken in" by firing the recommended number of rounds of the recommended type.
5) The user is familiar with the gun, ammunition, magazine, etc. and handles it per the instruction manual.
6) Revolver is being shot in Double Action mode

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General Operation:

Revolver: The user opens the cylinder, inserts the rounds, and closes the cylinder. He then points the gun at the target and squeezes the trigger. The action of squeezing the trigger rotates the cylinder to align a round to the barrel and retracts the hammer. Once the trigger has be moved back far enough to release the hammer, the gun discharges the round.

Semi-Automatic: The user loads the magazine with the ammunition and inserts the magazine into the gun. He then cycles the slide to load a round in the chamber which cocks the hammer/firing pin/striker priming the firing mechanism. He then points the gun at the target, releases any safety mechanisms, and squeezes the trigger. The gun discharges the round and then cycles the slide to load another round into the chamber. The cycling of the slide re-cocks the hammer/firing pin/striker re-priming the firing mechanism.

Note that in a semi-automatic that as long as there was a round in the magazine to load into the chamber, the gun is ready to shoot the next round. After discharge in a revolver, the discharged round remains aligned with the barrel hence squeezing of the trigger (or cocking of the hammer in a single action revolver) is needed to move a live round into firing position.

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Definition of Critically Levels:

Low: Round does not discharge and/or exits the barrel but the gun is capable of discharging on next trigger squeeze.

Medium: Round does not discharge and/or exits the barrel. Manual action is required to set the gun for next use.

High: Round does not discharge and/or exits the barrel. Gun system will no longer operate.

Severe: Round does not discharge and/or exits the barrel. Damage occurs to the gun system or injury to user.

Note: Normally a probability is given for each failure mode. However there are little statistics available on these failures, hence no probabilities are used in the analysis.


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A High Level Listing for Credible Failure Modes for Each Component:

The high level credible failures for reach component of the gun system (gun, ammunition, magazine, and user) are detailed.
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Gun:
The high level credible failures for revolvers and semi-automatics are detailed.

Revolver:
-Failure to properly align the cylinder to the barrel.
Results in bullet not discharging or not properly going into the barrel. Possible damage to user and gun.
Criticality: Low to Severe. Low if cylinder aligns properly on next trigger pull. Severe if injury to user or damage to gun.

-Failure to strike the primer with sufficient force to cause it to discharge the round.
Results in bullet not going into the barrel (light primer strikes)
Criticality: Low to High. Low if next rounds discharges when user squeezes the trigger to fire the next round. High if gun will no longer strike primer with enough force.


Semi-Automatic:
-Failure to properly strip a round from the magazine and insert it into the chamber.
Results in a jam.
Criticality: Medium to High. Medium if user can clear the jam and another round can be inserted into the chamber. Severe if jam cannot be cleared.

-Failure to strike the primer with sufficient force to cause it to discharge the round
Results in a non-discharge.
Criticality: Medium to High. Medium if user can cycle the slide to eject the unfired round and insert a new round into the chamber. High if unfired round cannot be cleared and new round inserted.

-Failure to eject the discharged round properly
Results in a jam.
Criticality: Medium to High. Medium if user can clear the jam and another round can be inserted into the chamber. High if jam cannot be cleared.

-Failure to prime the firing mechanism for the next shot.
Results in a jam.
Criticality: Medium to High. Medium if after user manually cycling the slide, the next rounds discharges when user squeezes the trigger to fire the next round. High if gun will no longer strike primer with enough force (light primer strikes)

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Ammunition
The high level failures of ammunition and its effect on each type of gun are detailed.

-Failure of the primer to discharge even when the primer is struck with sufficient force (dud)

Revolver: Same as a light primer strike.
Criticality: Low to High. Low if next rounds discharges when user squeezes the trigger to fire the next round. High if all subsequent rounds also do not discharge.

Semi-Automatic: Same as a light primer strike.
Criticality: Medium to High. Low if after the user manually cycles the slide, the next rounds discharges when user squeezes the trigger to fire the next round. High if all subsequent rounds also do not discharge.

-Failure of the bullet to travel fully out of the barrel due to insufficient force (squib)
Revolver: Results in cartridge discharging with bullet entering the barrel but does not exit.
Criticality: Low to Severe. Low if user does not fire next round or bullet is lightly
lodged and will exit if next round pushed it through the barrel. Severe if bullet is tightly lodged and next bullet causes barrel to explode.

Semi-Automatic: Results in cartridge discharging with bullet entering the barrel but does not exit.
Criticality: Low to Severe. Low if user does not fire next round or bullet is lightly lodged and will exit if next round pushed it through the barrel. Severe if bullet is tightly lodged and next bullet causes barrel to explode.

-Failure of the primer to discharge immediately (hang fire)
Revolver: Bullet still in shell casing
Criticality: Low to Severe. Low if user does not fire next round. Possible severe if user squeezes trigger for subsequent round and round discharges when cylinder is not aligned to the barrel causing injury to user or damage to gun.

Semi-Automatic: Bullet still in shell casing
Criticality: Medium if after user manually cycling the slide, the hang fire round is ejected, new round is inserted into the chamber properly, and the gun is ready for next use.

-Backing Out of Bullet from Shell Casing
Revolver: Can cause cylinder not to rotate
Criticality: Low to Severe. Low if bullet back out des not interfere with cylinder rotation. Possible severe if bullet backs out far enough to stop cylinder from rotating.

Semi-Automatic: Bullet stuck in magazine
Note: All most not possible because of the way the rounds are held in the magazine.
Criticality: Low to Severe. Low as long as there is not issue with feeding the backed out round. Severe if the next round cannot be fed from the magazine.

-Failure to present the round properly so it can be stripped off and inserted into the chamber.
Revolver: Not applicable
Criticality: None

Semi-Automatic: Results in a jam.
Criticality: Medium to High. Medium if user can clear the jam and another round can be inserted into the chamber. High if jam cannot be cleared.

-Not allowing the slide to lock back after the last round in the magazine has been fired.
Revolver: Not applicable
Criticality: None

Semi-Automatic: No Impact
Criticality: Low as user can eject magazine, insert a new one, and manually cycle the slide.

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User
The high level failures of due to the user and its effect on each type of gun are detailed.

-Not properly holding the gun so as to inhibit semi-automatic from recycling properly (limp wrist)
Revolver: No Impact
Criticality: None

Semi-Automatic: Gun fires but does not cycle the slide properly causing a jam.
Criticality: Medium after user manually cycles the slide.

-Not properly loading rounds into a magazine
Revolver: No Impact
Criticality: None

Semi-Automatic: Results in a jam.
Criticality: Medium to High. Medium if user can clear the jam and another round can be inserted into the chamber. High if user must eject magazine, insert a new one, and manually cycle the slide.

-"Short Stroking" trigger (not pulling the trigger all the way)
Revolver: Gun does not fire but the cylinder rotates.
Criticality: Low as gun fires on next trigger pull

Semi-Automatic: Gun does not fire nor does the slide cycle.
Criticality: Low as gun fires on next trigger pull

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Other Factors to Consider:

"First shot" Reliability
A semi-automatic has an advantage over a revolver when firing its first shot (or subsequent shots if the gun has cycled properly after firing a round). The advantage for the semi-automatic is that to discharge a round, only the trigger release mechanism and the round have to function properly for the gun to discharge. This is because a round is in the chamber and the firing mechanism is "primed". In a revolver, the cylinder must cycle to align a fresh round to the barrel in order for the gun to function properly. If a revolver is being fired in "single action" mode, then this factor is negated.

Accuracy Repeatability
Assuming a gun is sighted in properly and the ammunition is consistent with what was used to sight in, there can be different point of impact based on the gun design.
Revolver: In most revolvers the sights (front and back) are structurally lined to the barrel. However the cylinder chambers are moved to alight with the forcing cone and the barrel. The alignment of the cylinder chamber to barrel varies with each chamber in the cylinder. This difference in alignment can affect the accuracy.

Semi-Automatic: Except for designs that have the barrel fixed to the frame, barrels on semi-automatics move after each shot and return to position for the next shot. Since the barrel and sights are not structurally fixed together, there can be variability from shot to shot with the barrel to sight alignment. However since the bullet is inserted snugly into the chamber which is part of the barrel, the bullet to barrel alignment is consistent from shot to shot.

Effect of gun powder residue on functionality (fouling)

When the cartridge is discharged, residue from the gun powder is propelled forward and out of the shell casing. This residue adheres to various parts of the gun mechanisms. The effect of the residue is different on a revolver versus a semi-automatic. Different ammunition produces different amount of gun powder residue. So the amount and effects of residue varies considerably between different ammunition.

Revolver:
In a revolver, the bullet is housed in the cylinder where it is discharged. The bullet and any gun powder residue are propelled forward thru the front of the cylinder, across the gap between the cylinder and the forcing cone, and into the barrel. Gunpowder residue is built up in the inside of the front of the cylinder starting at the top of the shell casing, on the front of the cylinder, on the forcing cone, around the forcing cone (and frame) and in the barrel. The effect can result in the inability to eject shell casing from the cylinder, inability to insert new bullets into the cylinder, opening of the cylinder, and the cylinder not rotating properly. This effect can be observed when firing a revolver that can use both .357 Magnum and 38 Special ammunition. Since the 38 Special bullet is shorter than the .357 Magnum, if it is shot before the .357 Magnum and causes built up inside the cylinder, then issues can occur when .357 Magnum ammunition is inserted into the cylinder-it may not go all the way into the cylinder. Hence the functionality of a revolver is significantly more affected by gun powder residueand more frequent cleaning is needed.

Semi-Automatic:
Since the bullet is discharged in the chamber which is part of the barrel in a semi-automatic, the majority of the gunpowder residue goes down the barrel and ejects out the gun. Some residue comes back into the slide, magazine, and frame. Some also comes out of the barrel and adheres to the front of the barrel plus the front and sides of the slide. The amount of gunpowder residue that adheres to critical parts of a semi-automatic is significantly less than in a revolver. Hence the functionality of a semi-automatic is significantly less affected and it can function reliability for more rounds before cleaning is needed.

Zogger52;
Drop everything, run, don't wast any time, get your application submitted to the finest, law school, of your choice! I feel sure that a scholarship awaits you at any law school. You have naturally, the required ability, needed by any fine lawyer to use 500 words to explain something, when 5 would suffice. You can be taught the other needed skills. Good fortune.
That's my 2¢ outlook on the matter.
Chubbo
 
A = quality revolver is always going to shine over a semi auto until you start talking about capacity. And that's because the semi auto is too reliant on the quality / condition of the ammo. You cant get around that.
 
Revolvers have more moving parts than semis, even double-action semis. Revolvers are more complex in operation. A semi is simplistic in operation. When a revolver fails -and revolvers will fail- it's usually catastrophic meaning it becomes a throwing weapon. While I've never had a good quality semi fail, drills I was taught to clear malfunctions took a few seconds and the semi was back in the fight. I have had S&W revolvers fail & were hopelessly useless until fixed/repaired.

I'd bet that the S&W Model 5904 was more reliable than ANY revolver EVER produced by S&W.

For self-defense, I'd take a Performance Center 3" Model 1911 9MM over ANY revolver.

I'd pit a Sig P229 against any revolver in competition of reliability.

Antiquated beliefs die very slowly. Some hand gunners, especially six shooters, refuse to believe that a semi is more reliable that their beloved revolvers. I'm good. It's their business, not mine.

The reality is revolvers are far more persnickety and vulnerable to catastrophic malfunction than are good-quality semis.

BTW, I Love J-Frame revolvers.
 
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You're going into a life or death duel. There are two of the best handguns you can think of on the table; one is your ideal double-action revolver, the other is your ideal semi-auto pistol. You have first choice. Your opponent, who is as equally skilled as you, will use the other.




Result of the duel: you're both dead. ;-)


PS.
No man can whip me in a fair fight.

That's because it's not fair to chase a man down and then whip him.


God bless,
Birdgun
 
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For full size semis intended for professional use, I would agree that semis in this class are very reliable. For small concealed carry handguns, I don't think semis are as reliable as revolvers, especially when you get down to pocket size handguns.
 
I'll make this short/sweet. A VERY knowledgable firearms instructor once told me this:

"Look at nearly any situation where a good guy failed to stop a bad guy during a shootout and you'll find it's most often a lack of marksmanship, not equipment failure."

Are there exceptions to this rule? You bet. Is lack of marksmanship often the failure though? Yup.

I don't focus on the variables...I just can't. Modern day, well known manufacturers of firearms and ammo make great products. The ONLY way to sort out the few lemons is to spend tons of time with the product. When it comes to ammo, this is a complete and unpredictable variable...you pick the best you can find and hope you don't get the 1:1,000,000 dud round. Even data about "stopping power" is all over the place...there are tons of shootings where a typically lethal hit will not stop someone for some reason or another. Again...I cannot focus on this as is is just another variable.

After that, once I cycled a single firearm enough to be relatively sure I don't have a lemon in my hands...the only constant is me and my lack of shooting ability.
 
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Reading the comments I see people are not looking at how often does a semi auto have a malfunction versus a revolver. I have a Rossi clone to the S&W 36 that in the 30 years I have had it I have never had the gun malfunction.

If a round doesn't fire in a semi auto then it has to be racked to clear the dud round where as the revolver same scenario just take another pull of the trigger for it to go bang. Yeah if you don't have both hands available then racking a SA slide to clear a misfire or jam can be quite a problem.

How about a safety malfunction? Much more prone to that with a SA than a revolver. Why? Revolvers basically don't have a safety to fail or get moved out of position.

SA are known for feeding problems and having a stove jam. How often does that happen with a revolver?
Okay a revolver can have a jam due to the bullet coming forward from the casing due to recoil and jamming the cylinder to the frame but how often does that happen? I shoot mostly just revolvers and in the past 30 years I have had that happen only once. The casing had a hair line crack in it.

HMMM A SA having a jam due to a magazine feed problem, Oh yeah I have experienced that more than a few times. How many times I have read where the magazine release button got hit and dropped the magazine. If the magazine doesn't get locked into position then what happens? Gee I have yet to read of that happening with a revolver.


Sorry but from my experience the revolver scores a nine for being safer and more reliable than a semi auto reliable/safety rating of a six in my book of experience.

Funny how some perspectives don't look at the whole picture. From my experience over many years the revolver is still the most reliable.

People say a Glock goes bang every time. From experience I know that is a myth.

I will continue to carry my revolver and the SA can sit in the safe.
 
I believe why the military chose the SA over the revolver was because of capacity and reliability in bad conditions. I believe that also applies to police forces. But that's my opinion.
Then again there is a big difference between a military or police application versus a citizen protecting themselves where there is probably less than a 1% chance of the citizen having to use their gun of choice. Granted a semi auto very possibly could function better in very dirty military situations.
 
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Statistical Reliability Comparisons

No this is not spam.

I was hoping for a more 'engineering' based answer. I am not a mechanical engineer, but have electrical and software engineering experience. My knowledge of mechanical reliability is basically none.

The comments here agree with my experience. I have found Glocks, Pre-lock J-Frames and N Frame competition models with Locks to be extremely reliable. I have only had ONE J-frame fail due to a broken part and I have had my glocks fail in competition due to me breaking off a adjustible rear site.

However, other brands and firearm types have failed me right out of the box or shortly after. Colt's including double action revolvers and 1911s, Kahr's, and a Beretta.

I tend to watch reviews closely and am disheartened when I see brand new guns failing regularly or having minor issues that preclude their use in competition or self defense. The issue of the GP100 7 shot is an example of why I don't think most new revolver's can be trusted based on the engineering processes that bring them to us.

I am not saying all the guns today are bad, I am saying SOME of the processes used to make them are NOT suitable for creating a competition gun or self defense product. I think MOST revolvers today are relegated to the 'consumer' side of the house where the assumption is that these guns may require a customer service call at a rate higher than the Semi-Autos used in LEO.


For the record, I am a mechanical engineer, albeit not a specialist in mechanisms, but a firearms enthusiast, nonetheless, familiar and experienced in many of these issues of comparative reliability and durability. All of the recounts on this thread are anecdotal with zero control. I will confess to say that it is intuitively obvious that the simpler revolver mechanism is inherently more reliable in most situations, but that is my subjective opinion. This argument can never be resolved, for there are many classes of comparison. The one I see neglected is how reliable is the firearm to be drawn and fired six or eight times without reloading and not stop, the charging bear scenario. I wish somebody would sponsor me to evaluate this scenario. For most of us civilians I would assert that this case is the one that matters. We are not fighting a war (yet), battling street criminals (yet), or firing thousands of rounds in a competition without cleaning. Too many of these reliability assertions are predicated on one of these scenarios. Militaries and police forces need high capacity repeaters, which overwhelmingly bends the preference to semi-automatics.

Here's my controlled test. Pick a revolver and semi-automatic from similar price points (very important) with similar downrange ballistics from a similar caliber (no .22's against .45's). Procure five samples of each from a retail outlet, pre-qualify each break in each piece with ammunition that each will feed properly (important for the semi). Then bang away in an environment without variables that influence outcome like snow or mud. Five shots, reload, clean up with a simple wipe down. Repeat until a statistically significant number of failures occur, but a minimum of 1,000 rounds from each pistol, a total of 10,000 rounds. Count all the failures including stupid human mistakes like hitting a mag release in the middle of a string. From this data one can easily calculate the mean number of shots between failure. If you think this scenario is biased in favor of revolvers, I guess it is because there is virtually nothing that can go wrong, especially if you decided the scenario was to be single action only. Complexity is the enemy of reliability. Maybe double action only for the revolver is more valid if you define the scenario to be reasonably rapid fire, i.e. at the charging bear.

Any scenario could be evaluated that would have validity if properly controlled to eliminate extraneous variables. This will likely never happen because manufacturers don't want hard data out there to be used against them in their competitors' ad campaigns.

In the end the real statistical differences in reliability are probably de minimus for we civilians, which leaves us choosing pistols for reasons of personal preference, familiarity, suitability for the mission, emotion or whatever. Those reasons are more valid and pertinent than hard statistics that show up beyond the second decimal place of standard deviation.
 
HUH?

All I can say is that my response is now #151, and NOTHING appears to be settled. Truth be told, I CANNOT drink enough coffee to adequately participate in such a urination contest effectively... I just don't have the bladder for such things at my age.

SO, what I CAN SAY IS, make sure you bring your own towel, because all get urinated on and you are responsible for drying yourself off... :eek::mad::rolleyes:

BTW, watch out for fire hydrants because you will probably find competition around those more than you can handle... ;)
 
All 4 of my Smith and my 1 and only Colt revolvers.. I can honestly say have only failed due to screws backing out and it was only once. I had light strikes with BB .45Super ammo and Blazer Brass (same outing) in my M625. So one out of 6 chambers failed to fire with the first pull. A second pull and they touched off. A little purple Loctite on the strain and cylinder release screw and it never happened again.

I've had my 1911's fail to cycle due to spring fatigue and one M&P40 that locked up due to sharty Remington Green Box ammo bought out of desperation during the 13' ammo shortage. Magazine springs replaced and garbage ammo thrown in the s#it can and no more problems with my 6 semi-auto's.

All in all, I'd say my revolvers and semi-auto's are 99.98% reliable and on par with each other in that department. I won't have a firearm that isn't reliable.
 
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