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ArmaLube
June 10, 2004, 01:25 PM
Pistol Recoil Springs

Pistol recoil springs should, as a general rule, be of the heaviest rating that does not impair functional reliability of the firearm. A simple way to judge the suitability of recoil spring tension is to observe the ejection distance of fired shell casings. It is said that ejection distances of 3 to 6 feet indicate appropriate spring strength. Ejection distances significantly beyond 6 feet indicates the need for a heavier spring. Note that the correct spring strength is influenced by ammunition load characteristics, firearm design, buffering devices, and other factors. Unduly light recoil springs increase the probability of serious firearm damage occuring.

Spring Fatigue

Wolff Springs states that their springs will last for a minimum of 3000 to 5000 rounds before replacement would be necessary. Assessment of recoil spring fatigue may be accomplished by monitoring shell casing ejection distances (taking into account cartridge load characteristics) on a continuing basis. However, it would be even better to measure spring compression strength, using a suitable scale and test jig.

Magazine Springs

Considerably divergent viewpoints exist relative to proper management of magazine springs. Some believe that long term spring compression results in fatigue. Considerable evidence and respected experts generally represent that long term storage of fully loaded magazines does not result in weakened springs. A variety of reports indicate that loaded magazines stored for several decades performed perfectly when placed in active use. In fact, it is frequent cycling of springs that predominantly causes gradual weakening.

Spring References

http://www.ist.org.uk/fatigue_tester.htm
http://www.dawsonprecision.com/allabout/recoilsprings.aspx
http://www.yarchive.net/gun/spring_fatigue.html
http://www.gunsprings.com/1ndex.html
http://online.cctt.org/physicslab/content/PhyAPB/lessonnotes/springs/lessonsprings.asp
http://www.sportshooter.com/gear/wolffspringsfaq.htm

An Extensive List Of General Gun Related Reference Links

http://yarchive.net/gun/index.html

LawDog
June 10, 2004, 08:44 PM
If you don't mind, I'll just scoot this one over to the gunsmithing section.

LawDog

Handy
June 10, 2004, 09:12 PM
Armalube,

I must disagree. I don't know where your information hails from, but changing spring strengths from factory settings for no good reason is a mistake. The manufacturer carefully designed the slide and barrel mass along with the spring strength to function correctly in a variety of environments and provide a slide velocity that affords good engagement of the fed round, buffering at the rear of slide travel and a reasonable velocity as the slide returns to battery.

A higher strength recoil spring will often increase felt recoil and increases the velocity that the slide closes at. There is no reason to slam the slide closed any harder than it already is - it does no service to the locking surfaces that arrest that movement.

While 3 to 6 feet of ejection might seem dandy at the range, the spring is now limiting the guns ability to eject when dirty. Add a little sand to a gun with overly strong recoil springs and that designed in reliability goes away.


By all means, replacing gun springs periodically is a good idea (and Wolff a good brand), but the assumption that every gun makers engineers don't know their business is laughable. 14 lbs springs do not cost more than 12 lbs springs - those springs were chosen as the correct weight for that gun by people who know alot more about such things than you or I.

1911Tuner
June 11, 2004, 06:48 AM
Handy nailed that one. The thing to keep in mind is that springs work both ways. Increasing the loading of the spring to buffer the impact in recoil
causes increased battering of the slidestop crosspin and the lower lug feet.
Slower backward means faster forward. A heavier than standard recoil spring
makes magazine timing more critical. If the slide outruns the magazine, you
can get Bolt-Over-base stoppages...aka Rideover Feed. Those can be dangerous. This little glitch generally happens on the last round.

The 6-Foot rule assumes that everything in the gun is optimized, and the
point that the brass hits the ground can be changed with a slightly different shape on the ejector nose, or as little as .001 inch difference in extractor hook length. The shape of the extractor hook...especially at the bottom corner...can have a signifigant effect on where the brass lands. The effect
of the mainspring is also a player in the slide's rearward speed and momentum. Get your pistol to drop the brass exactly 6 feet away, and go to a heavier mainspring for a demonstration. Use a firing pin stop with a small radius, and it gets even more interesting.

The other rule...Using the heaviest spring that will allow slidelock with a
loose grip is also only half the story. Several pistols will do that trick with a spring loading that is off the scale...but it tends to make the pistol grip-sensitive. Choosing the spring that will allow the pistol to function through
two magazines while gripped with the thumb and index finger with your wrist
broken on two planes is a better test of the correct spring rate.

Luck!

Tuner