Polymers in your gun, especially in the role of a spring.

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mcb

mcb

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Spun out of the Remington Bankruptcy thead so as to not get that thread to far off topic.

The RM-380, as @chicharrones found out recently, uses a small slug of elastomer as the spring for the extractor. This started a discussion of elastomers and their use in firearms and rather than go off topic there I wanted to start this thread.

I personally don't have an issue with elastomer springs but many see this as a way gun companies are going cheap. I would certainly concede that price is a driver in this but elastomers also offers function, in the form of damping that a spring alone cannot do.

Not only did the RM380 have a pure elstomer spring for its extractor so did the DPMS Gen II. I have shot both a fair amount and never had an issue with them. Not to mention the elstomers in just about every AR-15 buffer weight that we never think about.

They certainly do not have the shelf life of a metal spring but they always performed well or better than a spring for me in places were it was designed for properly.

As for exposure to gun cleaners and lubricant I have never had an issue with that exposure and good modern elastomers/polymers. There are lots of gun using polymers for many things now and its been a non-issue on their exposures to nearly all gun related chemicals. Polymer frames, magazine followers, grips, handguards, stocks, etc.

Polymers specifically elastomers are everywhere now, my guns, my bikes, my vehicles, everywhere.

So is it space age technology? Just being cheap? or some combination of both when used in guns?
 
Space age technology and, if properly engineered, can last much longer than springs in applications like this.

My favorite example of "can elastomers handle the stress of real world applications" is helicopters.
489092_1_En_6_Fig2a_HTML.png

The "flexbeam" in this drawing is a set of elastomeric beams and bands (one part is shown below) that replace several bearings. Much longer life, something like 90% less maintenance (you still have to crawl up there and inspect, but that's easier, and there's no lubing, etc.).

YES, this is a different application, but have been in use for decades. Properly selected, and ideally with the system around it designed to take the best advantage, elastomeric parts can be very useful. They should have much LONGER service life than springs, especially in the difficult way springs are often used in guns, with far too much compression causing premature wear and replacement every few thousand cycles.
 
The loads on those strap-packs/flex-beams in helicopters is amazing. I have worked on rotor-craft in a former job and was amazed at the loads generated on a rotor hub.

Even more mundanely my down-hill mountain-bike back when I was racing use stacks of elastomers for the spring and damping in the suspension. By changing the stack of elastomer slugs you could tune both the stiffness and damping ration of the fork to match both the rider's weight and the type of riding.

I know our vehicles are still primarily spring over oil damping but everything else in a cars suspension is elastomers, all the joints for swing arms, shocks, struts etc have elastomer lined isolation bushings and the over travel stops are all elastomers.
 
Probably both; without the all-in cost comparison of each choice, one cannot say. Old school will say “cheap”, new thought will be improved and less expensive - I do not know. I do know that real change always follows a coffin - if “X” doesn’t work, move onto “Y”, then onto “Z”. Most people are uncomfortable with change and ironically, it is the only guarantee in the universe. I like steel firearms and I have zero complaints about synthetic materials - I like the heft and the feel - it is my personal choice that does not reflect on other’s choice.
 
I really don't mind polymers, elastomers, or whatever for grips or furniture. Clearly I have to put up with them as buffers in many autoloading guns, especially blowback guns.

I don't like that Remington has chosen to use a small button of elastomer solely as an extractor spring in the RM380 whereas the original design of the parent gun made by Rohrbaugh uses a steel coil spring in the same location. For the record, I bought my RM380 new in May of 2016.

The Remington RM380 parts diagram on page 33 here.

Considering pocket guns are typically carry a lot and shoot a little, it may be some time between the last successful range session and a potential self defense situation. In my case, I didn't notice the extraction issue with my RM380 until after I was doing a regular dust bunny cleaning session yesterday. Now the gun is sitting in the safe until I get a parts order together.

Now, starting with a clean gun and chamber the little RM380 should extract well for at least a couple magazines even if the extractor was removed. However, if you have to perform a tap-rack drill, you're screwed. Might as well carry an extractorless Beretta tip up barrel in that case.

As much as I really like the RM380, this elastomer spring makes me doubt carrying it anymore. Which is exactly why when people bring up survival guns and air guns in the same paragraph, I can't fathom ever relying on something that requires modern o-rings in an airgun for over a couple years old. I've repaired several of my airguns that suddenly develop blowout leaks, and those are all simple low pressure spring piston, pump, or CO2 airguns.

Plus, my experience in my industry with o-rings and molded/machined "rubber" materials has shown me that anywhere from a couple of years to 2 decades that these materials have to be replaced. Usually noticed due to hydraulic/pneumatic leaks or chemical break down "melting" material or dried out material.

Of course, I'm not talking about aircraft grade material with the high inspection rate of aircraft systems either. Especially when a shelf life limit or hours of use limit has been reached, which should dictate replacement right then and there.

Anyway, today I have my Taurus 85UL in my pocket. Sure it has a Crimson Trace polymer grip with "rubber" molded button inlay. But neither of those would prevent the gun from working if they degrade. ;)
 
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chicharrones said:
I really don't mind polymers, elastomers, or whatever for grips or furniture. Clearly I have to put up with them as buffers in many autoloading guns, especially blowback guns.

I don't like that Remington has chosen to use a small button of elastomer solely as an extractor spring in the RM380 whereas the original design of the parent gun made by Rohrbaugh uses a steel coil spring in the same location. For the record, I bought my RM380 new in May of 2016.

The Remington RM380 parts diagram on page 33 here.

Considering pocket guns are typically carry a lot and shoot a little, it may be some time between the last successful range session and a potential self defense situation. In my case, I didn't notice the extraction issue with my RM380 until after I was doing a regular dust bunny cleaning session yesterday. Now the gun is sitting in the safe until I get a parts order together.

Now, starting with a clean gun and chamber the little RM380 should extract well for at least a couple magazines even if the extractor was removed. However, if you have to perform a tap-rack drill, you're screwed. Might as well carry an extractorless Beretta tip up barrel in that case.

As much as I really like the RM380, this elastomer spring makes me doubt carrying it anymore. Which is exactly why when people bring up survival guns and air guns in the same paragraph, I can't fathom ever relying on something that requires modern o-rings in an airgun for over a couple years old. I've repaired several of my airguns that suddenly develop blowout leaks, and those are all simple low pressure spring piston, pump, or CO2 airguns.

Plus, my experience in my industry with o-rings and molded/machined "rubber" materials has shown me that anywhere from a couple of years to 2 decades that these materials have to be replaced. Usually noticed due to hydraulic/pneumatic leaks or chemical break down "melting" material or dried out material.

Of course, I'm not talking about aircraft grade material with the high inspection rate of aircraft systems either. Especially when a shelf life limit or hours of use limit has been reached, which should dictate replacement right then and there.

Anyway, today I have my Taurus 85UL in my pocket. Sure it has a Crimson Trace polymer grip with "rubber" molded button inlay. But neither of those would prevent the gun from working if they degrade. ;)
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Can't argue with you too much but I am still carrying my RM380 with no loss in confidence. I will replace the elastomer here in a few more years. Back when I was shooting my XD-40 a lot in competition I was running a lighter-than-factory recoil spring and I would have to replace it every ~5000 rds. I knew it was time to change when I could shake it out of battery, that was basically a new recoil spring each season. So replacing the RM380 extractor spring on a semi regular basis would not bother me. I wonder if the metal spring for the Rohrbaugh version would fit or if Remington changed the extractor design too much for the original spring to be installed?
 
I have considered myself fairly mechanically competent in the past but I have to ask, why does a spring (which acts as a dampener in certain applications) need to be replaced by a [polymer] dampening spring?

Sometimes reasons for change are thought up after the change takes place when the real reason for the change was being cheap (Ruger 10/22 and Remington plastic trigger groups) Sometimes design changes are cheaper solutions that time shows are adequate or sometimes superior alternatives (Savage barrel nut).

In my world, durability is paramount. Superior performance that is short term takes a back seat to acceptable performance and high endurance. Manufacturers have a dubious history with building items to be durable before all else and they often hide the reasons for building in short term durability for increased performance somewhere else.

The question needs to be asked, is the performance worth it? To me, usually not. For instance, accuracy. Accuracy has long been an overhyped benchmark of rifle construction.Apparently, if you can make the rifle accurate, then it is good to the superiority of all other measures. Well, Remington 783s, Savage Axes, and Ruger Americans are all accurate. But they are not much else but cheap. I would still buy one but they are what they are. Cheap.....and sell by the bucketload because and in spite of it.

I sometimes wonder if the manufacturers have the consumers best interest in mind when they build defensive weapons. When it comes to my life, I don’t exactly want the least expensive tool for the job and I definitely don’t want a gun full of parts that provide short term solutions that are marketed as “features”.
 
earlthegoat2 said:
I have considered myself fairly mechanically competent in the past but I have to ask, why does a spring (which acts as a dampener in certain applications) need to be replaced by a [polymer] dampening spring?

Sometimes reasons for change are thought up after the change takes place when the real reason for the change was being cheap (Ruger 10/22 and Remington plastic trigger groups) Sometimes design changes are cheaper solutions that time shows are adequate or sometimes superior alternatives (Savage barrel nut).

In my world, durability is paramount. Superior performance that is short term takes a back seat to acceptable performance and high endurance. Manufacturers have a dubious history with building items to be durable before all else and they often hide the reasons for building in short term durability for increased performance somewhere else.

The question needs to be asked, is the performance worth it? To me, usually not. For instance, accuracy. Accuracy has long been an overhyped benchmark of rifle construction.Apparently, if you can make the rifle accurate, then it is good to the superiority of all other measures. Well, Remington 783s, Savage Axes, and Ruger Americans are all accurate. But they are not much else but cheap. I would still buy one but they are what they are. Cheap.....and sell by the bucketload because and in spite of it.

I sometimes wonder if the manufacturers have the consumers best interest in mind when they build defensive weapons. When it comes to my life, I don’t exactly want the least expensive tool for the job and I definitely don’t want a gun full of parts that provide short term solutions that are marketed as “features”.
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So a classic wire wound mechanical spring offers almost zero damping. The elastomer spring can bring a specified amount of damping from a little to a lot and produce non-linear spring rates if desired. Both beneficial in many ways if designed correctly. They are also lighter in most cases and this is nice for the carrier and even better if on a part of the weapon that is reciprocating. That does not necessarily offset the real and perceived longevity issues in many cases but a elastomer spring can do things a metal spring cannot.
 
chicharrones said:
A coil spring supplemented with an elastomer bumper makes some sense. A small plug of elastomer used all by itself as a spring makes a lot less sense to me. Kinda why I dislike buffers in some autoloaders, you just can't count on them to last as long as other springs in the gun. Time and oils are not friendly to "rubber" types of materials.
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My Marlin rifles (Model 9 & model 60) have plastic buffers that have disintegrated . now I replace them at 5k round intervals.
 
mcb said:
Can't argue with you too much but I am still carrying my RM380 with no loss in confidence. I will replace the elastomer here in a few more years. Back when I was shooting my XD-40 a lot in competition I was running a lighter-than-factory recoil spring and I would have to replace it every ~5000 rds. I knew it was time to change when I could shake it out of battery, that was basically a new recoil spring each season. So replacing the RM380 extractor spring on a semi regular basis would not bother me. I wonder if the metal spring for the Rohrbaugh version would fit or if Remington changed the extractor design too much for the original spring to be installed?
Click to expand...

Considering the RM380 extractor button (their term) is an oval, and the cut out in the slide accommodates that oval, I think a conventional coil spring would simply slip sideways in the button's cut out. I thought of two coil springs side by side, but experience tells me that doing that usually leads to the springs intermingling together into one locked up spring.

View attachment 938036
 
earlthegoat2 said:
In my world, durability is paramount. Superior performance that is short term takes a back seat to acceptable performance and high endurance.
Click to expand...

I agree, but if the increase performance is actually proven by data and the decreased longevity is documented and an increased replacement regimen is studied and publicized, I have zero issues with “New and Improved”.

Like the fork shock analogy, there is no metal spring that can offer the same performance in that package. And like in the analogy, the bike is just a toy. I have a truck when I need to get somewhere. In a range firearm increased performance with an increase in chance of malfunction is acceptable.
A smoother ride on a bike is acceptable if the fashion in which It may possibly fail still gets me home.
This can not be said of the elastomer parts in a firearm.
The fashion in which they fail renders the gun useless, usually.
However, a metal recoil spring, broken, does the same. Except we would say to have replaced it before it broke.
There must be enough test-to-fail trials with the same replacement regimen, and way to test with accuracy, an elastomer rod spring of unknown repute, too.

I am a fan of New and Improved!

Just not in my carry gun.

A 1911 aught to be easy to do in rubber...

Whelp, these panels won’t put themselves on the custom wine cellar corking room walls, so...
I’d better get back to putting them on and wishing they were mine!:D
 
Not all plastics are the same. I've seen enough durability out of a lot of plastic parts to trust them over steel. In the right application, with the right plastics. Using plastics for springs is not something I'm familiar with, but steel springs wear out and have to be replaced periodically too. And sometimes bad springs come from the factory. It hasn't been too many years ago that every spring in new CZ pistols and magazines had to be replaced to get them to run reliably.
 
mcb said:
The loads on those strap-packs/flex-beams in helicopters is amazing. I have worked on rotor-craft in a former job and was amazed at the loads generated on a rotor hub.

Even more mundanely my down-hill mountain-bike back when I was racing use stacks of elastomers for the spring and damping in the suspension. By changing the stack of elastomer slugs you could tune both the stiffness and damping ration of the fork to match both the rider's weight and the type of riding.

I know our vehicles are still primarily spring over oil damping but everything else in a cars suspension is elastomers, all the joints for swing arms, shocks, struts etc have elastomer lined isolation bushings and the over travel stops are all elastomers.
Click to expand...
...and they rip/tear/fail CONSTANTLY in automotive applications, though I think this is more a case of the car manufacturers selecting the cheapest materials possible which will last just long enough to get out of warranty rather than the lack of a material which would last the life of the car. They just wont give you the good stuff- planned obsolescence and all that.

I kinda have to wonder if Remington didnt throw a little of the same thinking into those extractor balls. A big problem with most guns, from the manufacturers' view, is that they frankly last too long. If the extractor fails in 5-10 years, its the sort of failure that might convince an owner to replace the gun with a new one, but not cause bodily harm (and a lawsuit) to the shooter.

Another issue I have with poly parts in general, and especially in firearms, is that they are degrading at largely the same rate over time (with ambient temperature, humidity, and UV exposure variables of course), whether you are using the gun or not- whereas the remaining service life of a spring can be estimated by the number of work cycles (in this case round count) they have endured.
 
Trey Veston said:
Bought a new Marlin 1894 three years ago that was having feeding issues.

Took it apart and discovered one of the issues was that the tube magazine follower was polymer and was cracked. Brand new rifle. Replaced it with a stainless steel aftermarket part.
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I refinished my neighbor's Marlin 336 that was made in 1965. Part of it involved taking apart the whole rifle including magazine tube. Steel magazine follower. I was worried I might find a plastic one and might break it unintentionally. Not only was it steel, it had no rust on it. I do believe steel is better used in some places.
 
I am still unsure of the technicalities involving this dampening and how it is an improvement.

If it is anything like vibration dampening, Stihl and Husqvarma chainsaws went from polymer isolator vibration dampening to steel spring isolators for vibration dampening.

It was pretty well known that the rubber isolators broke down and tore faster (had to be replaced more often) and did not dampen as well as the newer metal spring isolators.

Also the metal springs do wear out and break just like any other spring. However, at least in the design of Stihl chainsaws, it is much easier to inspect the spring equipped ones for wear and breakage and much more difficult with the rubber equipped ones. When a spring is worn it is misshapen and should be replaced soon and a broken one is...well...broke. Either way, identification is swift and sure. Not so with rubber.

Hopefully this is close to a parallel example but I think that since the opposite conclusions were reached it will not be.
 
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There is “New and improved, space aged technology” in metals and composites. Some folks use materials because they offer advantages in performance others use them for cost reasons.
 
Better function using cheaper material & fabrication I don't have a problem with. "Hiding" it behind an extractor, well, hmmmmm .... I'll have to waffle on that. I do sometimes use cleaning materials and/or heat that will harm anything short of metal, and if I don't know that it's there where I can't see it, then I might have a problem with its use. It's my problem, it's my fault for not knowing it's there, but stil ....
 
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chicharrones said:
As much as I really like the RM380, this elastomer spring makes me doubt carrying it anymore.
Click to expand...

Chicharrones, if it makes you feel any better I put over 800 rounds through my RM380 with no defects or problems at all.

I recall the first time I discovered the mint green elastomer “spring” I was a bit perturbed. I called Remington and was told that it should last for many years and thousands of rounds. I asked “How many thousands?” The man I spoke with said he did not have that info.
 
Pat Riot said:
Chicharrones, if it makes you feel any better I put over 800 rounds through my RM380 with no defects or problems at all.

I recall the first time I discovered the mint green elastomer “spring” I was a bit perturbed. I called Remington and was told that it should last for many years and thousands of rounds. I asked “How many thousands?” The man I spoke with said he did not have that info.
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Green? I wonder which one is considered the stiffer "spring", yellow or green?

I only saw yellow "springs" online and the one in my RM380 was yellow from the factory in 2016.
 
Trey Veston said:
Bought a new Marlin 1894 three years ago that was having feeding issues.

Took it apart and discovered one of the issues was that the tube magazine follower was polymer and was cracked. Brand new rifle. Replaced it with a stainless steel aftermarket part.

View attachment 938037
Click to expand...
Exact same issue I had with a Pardner Pump 20ga youth fun that I bought for my wife.

And to that point, early in life I got a lesson that shoved me firmly away from the use of plastics and polymers in guns. I borrowed my grandmas H&R999 to go shoot a revolver before buying a gun to use as a deer hunting handgun. It hadn’t been shot in years and I figured I would shoot it, clean it, and return it which in turn would protect something I expected to inherit. Long story short, the hammer strut broke when I cocked the gun the first time. $30 and a month later I had bought the part and paid a gunsmith to install it (in his truck, on lunch break at his day job, with me watching). As a teenager, that meant 5 hours worth of work which was a whole weekend of me working at the YMCA as a soccer referee for the little bitty kids.
 
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IMO anyone who uses polymer for any part in a firearm is only building firearms to sell - not to last (and there's a lot of companies doing that today). A chrome moly steel spring doesn't cost THAT much and steel will ALWAYS wear longer and perform better. Always.
 
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