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Walt Sherrill · January 14, 2013, 02:45 PM

This topic pops up here fairly regularly, and we hear all of the same old arguments. I've just summarized some of the commentary in the following.
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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 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![/B] But if, when fully loaded, the spring is NOT near it's design limit 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.

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 COMPRESSEDat 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.

January 14, 2013, 02:45 PM	#33
Walt Sherrill Senior Member Join Date: February 15, 1999 Location: Winston-Salem, NC USA Posts: 6,348	This topic pops up here fairly regularly, and we hear all of the same old arguments. I've just summarized some of the commentary in the following. ----------- 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 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![/B] But if, when fully loaded, the spring is NOT near it's design limit 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. 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 COMPRESSEDat 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.