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

[mcb]

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.

Then you only have springs no shock absorbers or rubber bushing on your vehicle's suspension?

There are a heaps of applications where polymer springs out perform steel springs and some of them are even in guns.

 

[jmorris]

IMO anyone who uses polymer for any part in a firearm is only building firearms to sell - not to last

And we hear how a water bottle will be in the ocean forever and no one worries about sticks of wood getting there at all, does a number on metal parts as well.

Even in long traditionally steel/steel roles polymers are being used these days.

• 55,000 Lb Maximum Vertical Load
• 150,000 Lb Maximum Drawbar Pull

 

[MechAg94]

How long can the polymer parts sit on the shelf? I am pretty sure I can buy a few spare steel springs and they will still be good to use 10 years from now. If that elastomer can do that, I am fine with it.

The M1 Garand I got from the CMP worked with the original springs from the arsenal rebuild decades ago. Guns are generally looked at as lasting well beyond our own lifetimes often with original parts. Most people are not shooting 5000 rounds a year and changing out wear parts all the time. That is why I ask about shelf life. If someone just shoots a few rounds a year, how long with the polymer springs function?

 

[Drail]

And we hear how a water bottle will be in the ocean forever and no one worries about sticks of wood getting there at all, does a number on metal parts as well.

Even in long traditionally steel/steel roles polymers are being used these days.

View attachment 944695

• 55,000 Lb Maximum Vertical Load
• 150,000 Lb Maximum Drawbar Pull

Well, THAT is replacing a layer of grease - not a steel part.

 

[lysanderxiii]

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?

The R51 also uses an elastomer extractor spring.

 

[Fiv3r]

Polymers have their place. Heres the thing, many firearms owners seem to have an intrinsic need for a $500 gun to last a century. Everything is an heirloom. Everything is to be passed down to their grandkids sired by (in some cases) children they don't even have yet. Springs are to be replaced, of course! Foolish not to However! However, every other bob and widget must be made of steel and last until the sun goes Red Giant and swallows us in its galactic furnace.

Yes we live in a throwaway society. Yes plastics are often used to cut costs. However, there are thousands upon thousands of applications where polymer not only costs less but also is superior to steel.

Sometimes steel is just a "feel good" material. Take trigger guards. Plastic ones feel cheap and maybe you could break them. I mean, if I hit it with a hammer the steel should hold up better, Right? Maybe. How often have you seen a polymer assembly breakout? But I get it. Im the same way. The feel and look of a steel trigger guard makes the gun feel more high end. I know I felt a bit miffed about the "cheap" polymer housing on my Charter Arms Undercover. Then I considered that the gun cost under $300, Ruger has been cranking out revolvers with polymer frames for over a decade that are MARKETED for having such a feature, and all of the wear and tear was going to be absorbed by the steel frame, something a "higher end" 642 didn't sport.

So does steel make me feel better? Yeah. Does it add an appreciable strength? Probably not 2 decades in to the 21st century. With there be a lack of difference in durability between a Glock 19 and 1911 stored in a sealed safe for 100 years? I doubt it. How about between the two on a car dashboard in the desert taking in 100 years of UV?...what?.

As far as wear items go, IMHO, anything that is designed to perform as a spring or have buffer qualities should be treated, inspected, and replaced as such. Make up your own schedule. Base it on arbitrary number or empirical examination. The fact is that it probably won't get worn out fast enough and without warning to get you killed. A lot of things would have had to go wrong for THAT to be the reason your ticket gets punched that day.

Edit to fix typo in date. We do not live in 2200.

 

[hdwhit]

Following what mcb said, and borrowing from Rush, "...no change is permanent; but change is."

 

[792mauser]

Having family in Georgia and S. Carolina

Sometimes polymer is better than steel. I had a Rock Island 38super rust itself closed in very short order. The glock 26 I dragged through the muck the next year took it in stride and only had minor blemishes on the internals.

 

[chicharrones]

How long can the polymer parts sit on the shelf? I am pretty sure I can buy a few spare steel springs and they will still be good to use 10 years from now. If that elastomer can do that, I am fine with it.

The M1 Garand I got from the CMP worked with the original springs from the arsenal rebuild decades ago. Guns are generally looked at as lasting well beyond our own lifetimes often with original parts. Most people are not shooting 5000 rounds a year and changing out wear parts all the time. That is why I ask about shelf life. If someone just shoots a few rounds a year, how long with the polymer springs function?

In the case of my RM380 that I bought new, 4 years for that elastomer extractor spring. Maybe, fifteen 50-round boxes of ammo through it.

Compare that to my Chinese SKS that I bought new in the early 1990s that has the original steel coil extractor spring, which still works perfectly.

 

[goose1]

How long can the polymer parts sit on the shelf? I am pretty sure I can buy a few spare steel springs and they will still be good to use 10 years from now. If that elastomer can do that, I am fine with it.

The M1 Garand I got from the CMP worked with the original springs from the arsenal rebuild decades ago. Guns are generally looked at as lasting well beyond our own lifetimes often with original parts. Most people are not shooting 5000 rounds a year and changing out wear parts all the time. That is why I ask about shelf life. If someone just shoots a few rounds a year, how long with the polymer springs function?

Designed properly the elastomer will outperform the steel but the elastomer life will degrade from Ozone and oxidation as it ages while the steel will only degrade from usage. If the elastomer is allowed to heat up it will degrade from usage faster than usage while cold. The designer should have included antioxidants in the formula and tuned the spring for optimal performance from cold to the cycling temperature but time will eventually win and degrade the material.

 

[silicosys4]

I bought a used desert eagle that came with two slides. One slide is original to the gun with a coiled wire extractor spring, the other slide is part of a conversion kit to .50AE and had the newer polymer extractor spring. When I tried shooting .50 with the newer slide installed, there was zero extraction. Empty brass still in the chamber after each shot.
Took the slide off and disassembled. The polymer extractor spring had degraded into a waxy substance that had to be scraped out of its recess in pieces. I took the much older coiled spring out of the original slide and installed it in the newer slide.
Guess what...perfect function with the coiled wire spring.
I ordered another polymer spring to replace the one that failed but that experience turned me off to the idea of polymer springs.

 

[chicharrones]

I bought a used desert eagle that came with two slides. One slide is original to the gun with a coiled wire extractor spring, the other slide is part of a conversion kit to .50AE and had the newer polymer extractor spring. When I tried shooting .50 with the newer slide installed, there was zero extraction. Empty brass still in the chamber after each shot.
Took the slide off and disassembled. The polymer extractor spring had degraded into a waxy substance that had to be scraped out of its recess in pieces. I took the much older coiled spring out of the original slide and installed it in the newer slide.
Guess what...perfect function with the coiled wire spring.
I ordered another polymer spring to replace the one that failed but that experience turned me off to the idea of polymer springs.

Yep. Springs for gun operation should be steel, IMO. Recoil, extractor, hammer, trigger, ball detents, etc.

Buffers, frames, grips, etc. can be some sort of polymer as those ultimately won't stop a gun from running if they happen to physically break down just from sitting around not being used.

Really, this whole thing of elastomer springs used as an extractor spring in a firearm is another case of Engineer vs. Field Tech. Where the engineers insist what the field tech is witnessing can't happen, won't happen, wasn't designed to happen. I've run across it several times in my many years as a field tech and always when a new technology is tried out. Doesn't matter if it is mechanical, electrical, or software.

 

[chicharrones]

And we hear how a water bottle will be in the ocean forever and no one worries about sticks of wood getting there at all, does a number on metal parts as well.

Even in long traditionally steel/steel roles polymers are being used these days.

View attachment 944695

Well, THAT is replacing a layer of grease - not a steel part.

Indeed.

One machine type I service started coming with a yellow version of that (UHMW) about 5 to 10 years ago with the intent of not needing lubrication of what used to be a steel on steel sliding motion. Originally sold to customers as being low or no maintenance, now it's probably being sold to customers as being better for the environment since oil or grease "isn't required".

Because of sales brochures, most customers believe no maintenance is required and never wipe the grit off of that UHMW that accumulates. So, the grit stays there and puts grooves in the steel that rubs against it. Then the steel cuts grooves in the polyethylene, which develops excessive clearance. Which means the polyethylene has to be replaced, but the sliding steel (now with grooves in it) cuts the polyethylene immediately. And the steel part is expensive and so is the labor to replace it.

The older machines with steel on steel and regular greasing intervals don't develop grooves, and those parts last for decades instead of being damaged in months. All due to lack of maintenance for something that was sold as being low or no maintenance.

 

[goose1]

Working with polymers and elastomers is what I do. Degradation from exposure is a factor of time and intensity. Firearms experience wide variation in both making it hard to design a perfect elastomer or polymer but people like glock do very well at it. Metal can take wider variation if properly protected with oils like most lubricants. I prefer Steel for firearms but I do have some made with other materials.

 

[chicharrones]

I finally got the parts for my RM380 from Numrich this weekend. The new elastomer "button" spring seems to have fixed the extraction issue. Hopefully, I'll get another 4 years out of this one.

View attachment 944507

A follow up to say the extractor issue of my RM380 returned. Maybe the "new" elastomer spring I installed in September was old stock?

After much investigation, I simply cut a small piece of emery cloth to go in the pocket that the elastomer button (spring) rides in. The emery is simply a shim trapped under the elastomer button.

Problem solved for now.

I sure wish this RM380 had a steel coil spring for its extractor or a flat spring like a KelTec.

 

[wiscoaster]

I think you should post that in the improvisations thread!!

 

[.455_Hunter]

I had no clue about this "feature" of the RM380 prior to seeing this thread.

Mine might need to go bye-bye...

 

[Demi-human]

sure wish this RM380 had a steel coil spring

Magnum research has a polymer ejector “spring” they sell as a part for the Eagle. Perhaps that one is a higher quality and could be cut to fit? It is, at least, bigger.

 

[mrmike7189]

Having family in Georgia and S. Carolina

Sometimes polymer is better than steel. I had a Rock Island 38super rust itself closed in very short order. The glock 26 I dragged through the muck the next year took it in stride and only had minor blemishes on the internals.

Not a big fan of plastic guns myself, but I do own a Glock26 and it is a fine handgun. When I ordered a replacement recoil spring assembly from Glock, I noticed that the old RSA had a polymer guide rod........the new ones are steel. That is a fine improvement imo (even Glock is using metal parts where it is needed)