Been playing with a few of my 3rd Gens, the 4586 lately. As mentioned in another thread, I'm setting it up to shoot 45 Super & have been trying different springs; heavier recoil & mainsprings.

After swapping some springs around today I decided I needed a way to more realistically see what the changes were doing so I made a homemade setup (sorry, no details, it's patent pending ) to use. Nothing scientific or laboratory accurate, but something that's relatable.

This is my observation:

Increasing the hammer/mainspring, to add resistance to the slide's rearward movement, is a helpful way to slow it's initial movement. After the slide has pushed the hammer down the mainspring's resistance appears to be neglible to the slide's movement.

In fact, the initial movement & unlocking of the slide/barrel has a higher reading, than say at mid-cycle, because of both the recoil spring's pressure (on the slide) as well as the mainspring's pressure (on the hammer against the slide). At the end of the cycle, with the slide approaching fully rearward, the full power of the recoil spring is seen only. So your reading goes up at the beginning, drops for a bit, then goes back up as the slide comes to a stop.

Here's the readings I came up with for the springs installed.

Initial readings = start peak in lbs. pressure, to move slide rearward, at ~ unlocking.
Final readings = end peak in lbs. pressure, at ~ fully rearward.

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Note: All springs are Wolff round wire springs, unless otherwise noted.

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M4586
springs:

recoil, 22#; (ISMI flatwire, GLC-22)
hammer, 22#

Initial: 17# reading
Final: 19# reading

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M1076
springs:

recoil: 22# . . . . . . . . . . . recoil: 22#
hammer: 20# . . . . . . . . . hammer: 23# (heavier)

Initial: 16# reading . . . . . Initial: 19# (increased because of hammer increase)
Final: 20# reading . . . . . . Final: 20#

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M4013
springs:

recoil, 22#; (ISMI flatwire, GLC-22)
hammer, 20#

Initial: 19# reading
Final: 18# reading

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M4516-1
springs:

recoil, 21#;
hammer, 17#

Initial: 15# reading
Final: 19# reading

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M1911 Government
springs:

recoil, 24#;
hammer, 28#

Initial: 26# reading
Final: 24# reading

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On the M1076 I increased the mainspring weight to compare the difference. I was surprised that it was a one-for-one increase of the initial peak reading. I didn't expect that.

Some of the pistols had the same weight springs installed but because they were in different models, & barrel lengths, the readings were different.

A heavier hammer spring also increases the trigger pull weight. On the M1076, the single action pull increased by ~1# when I changed from the 20# to 23# spring. This wasn't really very noticeable.

On the M4586, & M1076, the heavier hammer spring also changed the double action pull. This seemed more noticeable than the single action's change but unfortunately my trigger pull gage doesn't go high enough to read any of my pistol's DA pull so I can't state how much it changed.

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