Storing semi-autos with slide locked back?

[awaveritt]

My wife has acquired a Beretta 84FS 380 auto which she plans to use in case HD situations arise. Being a blowback design, she has to really work hard to rack the slide - not conducive to quickly bringing the gun into battery. I've tried to convince her that the gun is entirely safe to have a round chambered and left in decocked/safety on mode. But for now, she would rather just have the slide locked back, where she can simply insert a loaded magazine and close the slide to make the gun ready.

Since the gun is so difficult for her to operate, she is shopping around (maybe a Sig Sauer P238). But I really like the Beretta and it'll probably find it's way into my stable of handguns. But until I can convince her to do otherwise, will storing the gun with the slide locked back weaken the mainspring?

[LarryFlew]

Just an opinion but usually springs don't mind being compressed without losing spring. It's the actual use of compressed - release - compressed release that eventually wear them out. In other words actually using the gun weares the spring out much more than storing - GO FOR IT.

[DPris]

I wouldn't.
Denis

[TBT]

Yep. Locked back or fully forward, shouldn't matter.

[RickB]

Maybe a little Tueller Drill, to demonstrate the different reaction times for loaded vs. unloaded? The value of having a gun that can be put into action with one hand (while locking a door, holding a phone, throwing a frying pan, etc.).

[awaveritt]

Maybe a little Tueller Drill, to demonstrate the different reaction times for loaded vs. unloaded?

RickB,
I agree! However, while I've been a gun enthusiast for 40 years, my wife is taking baby steps to get comfortable with the idea actually using a gun to defend herself. I've decided to eventually get her a gun she can, at least, learn to easily operate.

Of course, the Tueller Drill scenario is a sobering reminder to us all, experienced or not

[RonR6]

I would just keep it chambered, safety on. Keeping it open leaves a space for dirt to enter, possibly making it inoperable. If you do keep the slide back, I'd like to see the look on that bad guys face when he hears that slide klunk forward.

[carguychris]

A few points about the 84...

I've purchased a used police surplus 84 that came with a badly rounded-off slide stop notch. When shooting, it would only lock back on roughly 2 out of 3 empty magazines. I have no idea whether this problem is commonplace; however, I believe it was caused by a prior user repeatedly dropping the slide with the slide stop, so I recommend against this practice. (FWIW I eventually fixed it by carefully reshaping the stop notch with a Dremel.)

If you use the overhand method- which I generally prefer regardless of the type of pistol- the open-top slide design gives you little to grab hold of. I've futzed several overhand speed reloads with my 84- something that's virtually never happened with the other pistols in my stable.

Bottom line: With this specific pistol, I don't like the idea of having to drop the slide to bring the pistol into action, particularly in a stressful SD situation.

[TunnelRat]

I wanted to mention making she she's doing a push with her dominant hand and a pull with her off hand. A lot of people try just using their off hands to pull the slide back. If you break it into both a push and a pull I find it makes a big difference for some shooters.

[Boncrayon]

Not wise on two fronts. First, the spring should not stay compressed for extended periods (days) of time. Second, if needed for self defense, the time to move a clip into the semi-auto and rack the slide is too time consuming in self defense. Most semi-autos have a safety and should have ready-to-use ability when safety is off. If the firearm is being stored, especially in unsecured areas, the ammo should always be separate especially around youth.

[Andrewh]

it is no different than keeping your mags fully loaded.
compressed fully is no different to the spring fully extended.

as said above, use wears springs out, not sitting in one state or the other.

if you don't think you should keep your slide locked back, why keep mags full?

[Walt Sherrill]

Just an opinion but usually springs don't mind being compressed without losing spring. It's the actual use of compressed - release - compressed release that eventually wear them out. In other words actually using the gun weares the spring out much more than storing - GO FOR IT.

There have been a LOT of discussions on spring life on this forum, and a search for MAG SPRINGS will probably give you the details, but here's a summary -- and keeping the springs compressed DOES make a difference in the case of certain mag springs, and it PROBABLY makes a difference with recoil springs. Normal cycling will cause some deterioration over time, but if the springs are properly matched to the task, not much.

The following is NOT just opinion, and there are plenty of technical sites that will substantiate the claims. Recoil springs and mag springs will deteriorate, over time, if kept fully compressed. Springs have design limits, and if they're kept compressed to or beyond that design limit, they deteriorate. Longer/deeper compression means faster decline.

Lots of mag springs aren't fully compressed (or near it) when loaded; some are. Most RECOIL springs probably ARE near full compression when the slide is locked back.

Think about TAPPET springs in a car motor: some of them cycle millions of times over the engines life, but we almost never hear of a failed tappet spring. They've been functioning within their design envelope. Cycling alone doesn't make them fail.
-----------

Unloaded springs don't deteriorate, but with loaded mag springs the story is different and can vary. It depends on how the spring is used, the design of the magazine, and the work the spring is doing.

We've had a lot of discussions on this topic here on the TFL, and some of those participating were people involved in spring production and design, along with a few engineers familiar with steel. What they all say is that a spring that is consistently and frequently pushed to it's design limits will fail more quickly than springs that aren't pushed so hard.

If springs wore out from being worked (compression) alone, tappet springs in cars would arguably have to be replaced a lot more often than they are - which is almost never. Those tappet springs are designed for the task, and they are seldom pushed beyond their design limits. A 7-round 1911 mag spring seems to be about as reliable as any spring around, including tappet springs, but springs in hi-cap or compact mags often are asked to do more than other springs and may not live as long.

New gun designs have given us smaller guns that do what bigger guns do. The springs in those smaller guns have to cope with the same rounds, but must do it within tighter, smaller spaces, and sometimes with less material. In some gun designs, the designers clearly consider springs to be a renewable resource and, by design, sacrifice spring life so that the guns themselves can do more than they'd normally be able to do.

Coil springs differ from leaf springs in at least one important way: the material in nearly all of a coil spring does the work, while in a leaf spring just a key area or two does most of the heavy lifting. Because the "work" a coil spring does is distributed throughout the spring, coil springs start to degrade with microscopic breaks in a lot of places. A leaf spring will often simply break, because the work there is done in a smaller, more concentrated area. Coil springs can break, but most often start to soften or sag. Leaf springs can sag, but most often will break.

Leaving any magazine or recoil spring COMPRESSED at or near that spring's design limit will weaken the spring. That's because a compressed spring is a WORKING spring. In a loaded magazine, that spring is trying to lift a column of ammo! In the case of a recoil spring, it's generally pretty fully compressed, so it's probably being stressed a bit. But if, when fully loaded, the springs are NOT near their design limits then there's not likely to be a problem -- as the designers built in reserve power. With some sub-compact or hi-cap mags, however, the space for spring metal that would have provided that extra reserve power has been sacrificed to make room for more rounds. The same is probably true with recoil springs in sub-compact handguns -- as the springs must handle the same loads with less slide mass, and do it with smaller springs that must fit in more confined areas. (Some of the suggested service lives of sub-compact recoil springs are MUCH, MUCH shorter than their full-size brethern -- but they're not CYCLING more often!!)

• In the case of 7-round 1911 mags and most of the 10-round 9mm mags in full-size guns, there's plenty of reserve. With most fully loaded sub-compact and hi-cap mags, the springs are often FULLY COMPRESSED at or near (or even past) their design limit. There's no reserve left!

A 7-round 1911 magazine that has been left fully loaded for decades may still have a long life ahead of it, if later used. It's like that tappet spring in a car engine -- it's been used well within it's design envelope.

Note: Wolff Springs recommends downloading a round or two for most mags, when the hi-cap or compact mags are left loaded for long periods of time. That's advice intended to prolong spring life, not to sell more springs.

Another source (not me) with technical information provided:

Stress over time does cause relaxation/load loss/creep.

If designed properly, it will not impact the function.

[Note: The original post from which this is copied had a number of very informative links from the Spring-Makers-Resource website, but those links no longer work. The site is still active, however, so you can dig the details out here: http://www.seoprofiler.com/analyze/s...s-resource.net

These links DO work (now... had some problems for a few minutes after first posting them...):

http://en.wikipedia.org/wiki/Elasticity_(physics)
http://en.wikipedia.org/wiki/Plasticity_(physics)
http://en.wikipedia.org/wiki/Viscoelasticity
http://en.wikipedia.org/wiki/Stress_(mechanics)

Just a snippet, taken from http://en.wikipedia.org/wiki/Viscoelasticity

"All materials exhibit some viscoelastic response. In common metals such as steel or aluminum, as well as in quartz, at room temperature and at small strain, the behavior does not deviate much from linear elasticity. Synthetic polymers, wood, and human tissue as well as metals at high temperature display significant viscoelastic effects. In some applications, even a small viscoelastic response can be significant. To be complete, an analysis or design involving such materials must incorporate their viscoelastic behavior. Knowledge of the viscoelastic response of a material is based on measurement"

It's really not a question of if.... it's a question of will it impact the function.

Properly designed, not really a concern.

[ShipWreck]

Great post Walt - I've had this discussion many times over the years - and some guys just start getting down right mean about the topic, sometimes.

I agree with ya. It can depend on different factors. I've had magazine springs start to wear out from being constantly loaded. I went back to my old habits from the 1990s - underloading by one for hi cap mags. Seems to work. I got tired of buying so many +10% Wolf springs to replace factory springs, so I went back to that.

[AH.74]

The bottom line for me is this: what condition is the gun intended to be in, for ready usage?

A- loaded with safety on, if applicable as in this case, or

B- unloaded, slide locked back.

I think the answer is clear. The gun is not intended to be left unloaded with the slide locked back. It is meant to be loaded and therefore ready to be used. You should not have to undergo any extraneous manipulations to make the gun ready if it's needed at a moment's notice.

[overhead]

It would appear tappet or valve springs in most engines don't mind being at full compression for long periods of time either or we would also end up with more broken/failed springs. When the engine is shut off, at least one of the springs is going to be at or near full compression often and maybe left that way for some time.

[Nathan]

So, ideally you would want to keep loaded and slide closed, but your wife's perception is that this is less safe. It is unfortunate that the student is controlling the instruction here, but that happens to a certain extent in lots of instruction.


The basic idea of a locked back slide and a loaded mag is not completely outside of the design limits for most handguns. It is outside of "normal" functioning, so I would suggest you look at it as something you have to address through PM's. I think if you had a pull gauge, you could pull on the slide and see the decline over time of spring performance. An easier way would by to buy a new recoil spring, measure it's length with a caliper, and measure daily. Every ~5% of shortening you should shoot and confirm function. When it quits functioning, use the next longest length(test fired) as your replacement trigger. The detail you go to will help you determine how to maximize spring life.

I'm thinking normally this type of gun never has its spring changed, so, I would guess monthly or quarterly is where your data will lead you. Even weekly is not bad as that is only ~$10 /wk.

[BuckRub]

Another one when you feel someone doesn't know how to operate the firearm, should they even have one laying around?

[TunnelRat]

Second, if needed for self defense, the time to move a clip into the semi-auto and rack the slide is too time consuming in self defense.

For carry yes. In my house I keep a magazine in my handgun with a round unchambered. If I don't have the time to pull the slide back to deal with an intruder in my home, the way it's built, the only explanation is he is in the room with me, and my two dogs. If he's already in the room with me and has "silenced" both my dogs and I don't have the time to rack a slide, then he is standing over me, and I am likely dead.

[TunnelRat]

Another one when you feel someone doesn't know how to operate the firearm, should they even have one laying around?

Different folks have different comfort levels. Passing judgement on who should or shouldn't own firearms is something I leave for folks like Diane Feinstein.

[Nakanokalronin]

What if she grabs the gun in panic to an intruder and accidentally hits the slide release some how? She has a hard time racking the slide and may not get the gun into a firing condition quick enough. Chambered is the only way to go for a HD or carry gun. Get her training and have her practicing a bit more.

On a side note, having some defense guns empty and some chambered is not a good practice. Safe queen guns in the safe, unchambered big deal. Home defense and carry guns, chambered always to keep the training and manipulation consistent. Sometimes you're not going to hear that "bump" that allows you to sit there for a few seconds determining where the sound came from.

Scared of a loaded semi-auto? Get a revolver and load every chamber. If you just have to have an empty chamber, have all of your defense guns with empty chambers while you get some training to do otherwise.

ETA: As far as the spring question goes, a good modern compressed spring will not wear out. It wears with use/compressing & decompressing.

Here's something from a physics forum who asked about mag springs in handguns, but it pertains to springs in general....

The phenomenon known as creep, as mentioned above, only affects materials at or above ~0.4x their melting point, in absolute temperature (kelvin). This is unlikely to be an issue in regular service unless your springs are made of something absurd like lead, which actually creeps are room temperature. (I am assuming the temperature increases as a result of firing the weapon are small)

Stress-strain cycles, on the other hand, play a major role in spring wear. Ferrous material like iron and most steels exhibit an infinite lifetime under a particular amount of stress amplitude - not the absolute stress, which is generally far less - (the so-called "fatigue limit"). Less ductile materials like aluminum and titanium have a finite cycle life regardless of the stress amplitude; however, parts designed with these materials generally have lifetimes in the millions of cycles and fail by different modes long before the lifetime is reached.

So obviously, the life of the spring depends on proper design and materials choice. The spring steel that your gun would most likely use is a moderately-high carbon steel, with potentially nickel, silicon and manganese alloying agents in small quantities. Properly designed, it would last far longer than the other components of the gun that are regularly undergoing thermal stress, diffusion, and much larger fatigue cycles.

It's safe to say that storing your mag in a properly designed gun, will not wear out the spring prematurely. However, removing 1 or 2 rounds would increase the odds that you are maintaining the spring stress below the critical fatigue limit.

As a footnote, springs in regular circumstances follow Hooke's Law, which states that F=-kx (k being a materials, or "spring" constant and x being displacement). Thus, spring force is linear to displacement. I saw this forum post from an article on the main page, and as a 4th year materials engineer student I couldn't resist signing up to answer your question. Hope this helps!

[Walt Sherrill]

It would appear tappet or valve springs in most engines don't mind being at full compression for long periods of time either or we would also end up with more broken/failed springs. When the engine is shut off, at least one of the springs is going to be at or near full compression often and maybe left that way for some time.

Just because a tappet spring is pressed down as far as the push rods and rocker arms can push it doesn't mean it was fully compressed or that it has reached or gone beyond it's design limits.

Similarly, just because a magazine is fully loaded or a slide is locked back doesn't automatically mean that either spring is fully compressed.

In the case of some compact or hi-capacity mags, fully loaded/locked back clearly pushes those springs to or beyond their limits. In the case of some recoil springs in full-size gun, they can't be compressed much farther. But that isn't the case with every gun, mag, or recoil spring.

Fully compressed means just that -- it's a specific state in which the spring can't be bent or pressed down farther. Engineers familiar with metals and spring design tell us that springs that are FULLY compressed (or at or near their design limits) and kept in that state for longer periods, will not live as long as springs that aren't worked as hard. Go to the Wolff Spring website and check their FAQ area and see what they recommend for hi-cap mags, for example.

Talk to someone who works with spring-powered air guns -- and there are a few who participate here. They'll tell you that leaving such a gun fully cocked leads to relatively rapid degradation of the springs that send the projectiles down the barrel.

Better yet, read some of the technical info in the links above, or do that search on "mag springs" I mentioned originally -- you'll find a wealth of information here, some provided by engineers who have first-hand experience with the topic.

[overhead]

Originally Posted by Walt Sherrill

Psychologists tells us that we often see and hear what we expect to see and hear. We are all prejudiced in that manner. But prejudices can be overcome.

Just because a tappet spring is pressed down as far as the push rods and rocker arms allow to go doesn't mean it was fully compressed or that it has reached or gone beyond it's design limits.

Similarly, just because a magazine is fully loaded or a slide is locked back doesn't automatically mean that either spring is fully compressed. In the case of some compact or hi-capacity mags, they clearly are pushed ot the springs limits. In the case of some recoil springs, they can't be compressed farther. But isn't the case with every gun, mag, or recoil spring.

Fully compressed is a specific state in which the spring can't be compressed farther. Engineers familiar with metals and spring design tell us that springs that are FULLY compressed and kept in that state (or compressed beyond their design envelope for longer period) will not live as long as springs that aren't worked as hard. Go to the Wolff Spring website and check their FAQ area -- and you'll see that they state that simple fact very clearly.

Better yet, read some of the technical info -- starting with some of the links above -- if you doubt it.

Hi Walt, I was not disagreeing with you. Just as I don't assume a fully loaded magazine's spring is at a "fully compressed" state, I also don't assume that a valve spring is at is "fully compressed" state when in normal operation. Forgive me, as a non-engineer, I may have misused a term. Let me be more clear, if I can. I don't assume a magazine spring is going to be damaged in a compressed state anymore then I assume a valve spring will be damaged by being left in a compressed state.

As far as what a psychologist might recommend, you might want to take that advice yourself, sir

[brentfoto]

The bottom line for me is this: what condition is the gun intended to be in, for ready usage?

A- loaded with safety on, if applicable as in this case, or

B- unloaded, slide locked back.

I think the answer is clear. The gun is not intended to be left unloaded with the slide locked back. It is meant to be loaded and therefore ready to be used. You should not have to undergo any extraneous manipulations to make the gun ready if it's needed at a moment's notice.

Agree.

[Walt Sherrill]

I don't assume a magazine spring is going to be damaged in a compressed state anymore then I assume a valve spring will be damaged by being left in a compressed state.

As far as what a psychologist might recommend, you might want to take that advice yourself, sir

To keep folks from thinking one (or both) of us is/ are nuts... I removed the "read what you expect to read" comment about the same time as you wrote your reply. But, tell me: what do you think I expected to read that I misread?

You apparently think "compressed state" and "fully compressed" are the same -- and I never wrote anything that suggests that to be the case. A mag with one round in it has a "compressed" spring. On the other hand, your comment that some tappets springs remain compressed while the engine is off adds nothing to the discussion UNLESS you believe some of those springs are fully compressed (or are compressed near or beyond their design limits). My point was that they likely aren't fully compressed, 'cause the engineers, as good engineers will do, build some slack into the spring's design. That's what Wolff Springs call the "design limits."

I mentioned tappet springs because others have suggested that springs only wear out from being worked. Working the springs isn't necessarily an issue, either -- as tappet springs see many millions of compression in their working lifetime, and darn few of them fail. I've never had to replace a spring on most of my standard 9mm (10-round) full-size mags. and the stories about WWII 1911s kept fully loaded in a drawer for 40-50 years that later function perfectly when fired, abound! Those old GI 7-round mag springs aren't pushed beyond their design limits.

On the other hand, I've had quite a few magazine springs for sub-compact and hi-cap mags give up the ghost. Those springs have to do more work than others springs, and if kept loaded, they are kept at or near their design limits. The springs in those applications lose on both counts: trying to make springs do more than they're normally asked to do, both while they work and while they're loaded and not working.

I was a big CZ fan for years -- and still am -- but don't have as many CZs as I once did. Did you know that the springs used in the 9mm full-size CZ 10-round mags, and in the 15, 16, and 17+ rounds mags all use the same spring? Only the followers and base plates are different on the higher capacity versions. Keep those mags fully loaded and tell me which ones are likely to fail first...

[overhead]

With regard to the "read what you expect" -- I removed that in a edit, about the same time as you wrote your reply. What did I expect to read that I misread?

You apparently conflated"compressed state" with "fully compressed" -- and I never said anything that can be interpreted to suggest they meant the same thing. They aren't the same. Yet your argument that some tappets springs remain compressed while the engine is off is meaningless UNLESS the springs are fully compressed. My point was that they likely aren't fully compressed, 'cause the engineers built some slack into the design.

Personally, I've had many magazine springs on sub-compact and hi-cap mags give up the ghost. Never had to replace a spring on most of my standard 9mm (10-round) full-size mags. I don't hear of many folks replacing springs in 7-round 1911 mags, either.

(I was a BIG CZ fan for years -- and still am, but don't have as many CZs as I once did. Did you know that the springs used in the 10-round mags, the 15, the 16, and the 17+ rounds mags all use the same spring? Only the followers and base plates are different on the higher capacity mags. Keep those mags fully loaded and tell me which ones are likely to fail first...)

The only mags I leave fully loaded, nowadays, are my carry gun and the gun kept in the gunsafe bolted to the floor near my bed. Everything else is left unloaded. And I shoot the other two guns at the range periodically, to assure myself they're still working properly.

What I meant was that I was not trying to disagree with you, I just did a poor job of explaining myself and defining terms. You assumed, maybe rightfully so, that I was disagreeing. I was comparing, rightly or wrongly, a magazine spring compressed within it's design limits with a valve spring compressed within it's design limits. It came to mind due to recent experience rebuilding a Continental engine from a 52 Ferguson tractor. The motor had been sitting for 6 or 7 years, only being run from time to time to circulate oil. The original valve springs were still installed. After some carb work and some valve adjusting the motor ran fine and the springs were still within specs as they are listed in the manual. I did not trust them enough to use them after I rebuilt the engine, but really I probably could have.

I do not own a CZ, I never have, so I cannot speak to their springs. They make fine weapons, I just have never owned one. And honestly, I have not ever researched which springs are used in which magazines for any pistol. The only magazine springs I ever had to replace were GI mags I used in my AR's. I had two mags which were causing issues so I replaced the springs and followers. Being that I replaced both, I cannot even say with any certainty that the springs were even the issue.

At one point I had a Browning Hi Power 9mm magazine that stayed loaded for over 10 years, but that was not intentional. I "lost" the magazine, I thought, while shooting. But it turns out I dropped it in a box and accidentally sealed it and put it in my attic. I did not find it until I happened to decide to go through all the boxes to reorganize. If I recall correctly, the magazine was in the box from about 1995 until sometime in 2005. I replaced nothing and it is still working today. That certainly does not prove a thing, but I was surprised it still worked. I keep other magazines loaded from time to time, but never for more then a year or so without unloading them at the range.

I apologize to the original poster here for taking things off track. Personally, I would have no issue leaving a magazine loaded, but I would not be comfortable leaving a slide locked back. I can change magazines fairly quickly if one fails, I am not so sure about recoil spring.