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Glock Spring Deformation

PostPosted: Tue, 01 Jan 2013 08:46:47
by gunderwood
There is a never-ending debate about leaving mags loaded and springs getting weak because of it. The standard engineering answer is that as long as the spring is operated in it's elastic range (i.e. not deforming), it's state of compression or elongation does not cause wear, but rather spring cycles (loading/unloading for a mag spring) are what wear a spring out. However, with manufacturers trying to fit every last round into the mag, it is likely that they purposefully deform the spring so it breaks in to an "exact" fit. This would seem to fit with the experience of many mags "loosening" up after a few uses. I now have a picture illustrating this very deformation for a Glock 19, Gen4 15rnd mag.

There is approx. 1/4" or 6mm of deformation in the spring after only a few uses. However, after the initial deformation, it appears that no additional relaxing of the spring occurs past this point. I'm going to pull apart a CC mag that's been loaded/range tested for years to verify this.

A practical application of this information would be, IMHO if you intend to use mag extensions, you should not load the magazine to capacity even once before installing the extension (or at least have new springs). Why deform the spring so much when you don't need too?

Re: Glock Spring Deformation

PostPosted: Tue, 01 Jan 2013 10:35:46
by Chasbo00
In addition to Gunderwood's excellent info, I'll add the following:

I shoot a Glock 19 in IDPA competition and I find I need to replace my magazine springs about every year and a half or so to ensure solid reliability. I have 8 magazines that usually each get used in a match, and it's only rarely that I load more than 10 rounds in the 15 round capacity magazines. I normally load up all the magazines the day before a match. I don't keep them loaded all the time.

The magazine is a critical component affecting the pistol's reliable operation. It's easy to forget that and not give the magazines the care and cleaning they may need. I've been guilty of this. My failure to properly inspect and clean my magazines following a match held on a sandy range cost me during my next match with a couple failure to feed stoppages. The springs were past due for a replacement as well. Take proper care of your magazines!