Springing for a new idea.

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While improvements in metallurgy have led to some improvements in firearms spring life it does seem peculiar that the modern firearm is so dependent on a device that almost belongs in a Steam Punk book. Look at all the devices used to "help" the spring in the form of after market guide rods, plus all the aftermarket springs to "tune" a rifle or pistol from outfits like Wolff. Springs not only wear out they vibrate, generate harmonics, and "TWANG".
I was thinking about "a bad idea". The French 75 mm gun of WW I fame used a nitrogen filled cylinder to return the gun to battery after it was fired. So I'm wondering with modern manufacturing methods could a small gas filled cylinder replace the recoil spring in firearms

[PawPaw]

I'm sure that you could, but at what cost?

When I got my first 1911 and found that it had a full-length guide rod, the first thing I did was replace it with a GI guide rod. It's been working fine for a decade or longer. I have one 1911 from the early 1920s that, while I'm sure that the recoil spring has been replaced at some point in the last 90 years, I certainly haven't replaced it. It's still running fine, and a replacement would cost me less than $10.00 and last for years.

Springs work. Until they don't, and they're cheap to replace.

[MarkD]

I can think of a few reasons it would be impractical.

It seems to me most of the time, springs give some warning before they fail completely. They'll weaken, not be as reliable, etc before they actually break. If you blow out a gas cylinder or the seal it'll stop working immediately, and it can happen with no warning.

Plus, it's real easy to get a new spring for a different application, so if you want to shoot bullseye with your .45 using bunny-fart loads all that' really needed is a new spring, and you can make one to replace the old one. Compressable gas isn't so easy to fine-tune.

Springs are less subject to temperature change than gas. Yes, they're somewhat affected, but the gas would be much more so as the gun heated up.

Sorry, but my impression is that this is a "If it ain't broke don't fix it" situation.

Especially since your proof of concept is a French gun....yeah, someone had to say it.

[Vonz90]

A properly designed steel spring has essentially an infinite cycle life time. When they do not it means they either were not properly designed or some compromise was made (for weight, cost, something).

All of the alternatives would have both a higher cost and shorter life (although some have positive features too). As you get bigger, springs do not scale as well, so that is when other options start to look better.

Trade offs.

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As a side note: one thing I don't like is dual thumb safeties on a 1911. They tend to make it harder to take the pistol down for cleaning and repair.