Mechanical Feeding
The mechanical process occurs during recoil from firing a round. The process happens as if the slide were forward and pulled to the rear manually, only faster and without action from the shooter. The following table describes the steps in the mechanical feeding process.
Stage Description
1 As the slide moves forward under pressure from the compressed recoil spring, the front of the stripping rib catches the rim of the top cartridge. Click here for figure 2-3.
2 The force of the recoil spring pushes the round straight forward.
As the cartridge moves forward, its rounded tip meets the inclined feed ramp on the receiver. Click here for figure 2-4.
3 The bullet tip inclines up toward the chamber of the barrel. The magazine lips still restrain the rear of the cartridge, but now, the tip of the round contacts the feed ramp that directs the bullet into the barrel. Click here for figure 2-5.
4 As the slide continues to move forward, the rim of the cartridge finally clears the magazine lips. The magazine spring continues to push the follower and any remaining cartridges upward. This has the effect of kicking the rear of the cartridges up into alignment with the barrel, completing the feeding process.
Chambering
Process The following table describes the chambering process.
Stage Description
1 As the cartridge kicks free of the magazine and aligns with the barrel, the rear of the cartridge rides up the face of the slide.
2 The rear of the cartridge then moves into the cartridge head closure (half-moon cutout) on the slide face. Click here for figure 2-6.
3 The cartridge head enclosure guides the rim of the cartridge behind the extractor hook, pushing the extractor outward and compressing the extractor spring. The chamber-loading indicator is now
visible.
4 The slide continues forward until the face of the slide meets the recoiled barrel. The round is now fully chambered.
Locking
Process Once chambering is completed, locking begins. The following table describes the locking process.
Stage Description
1 When the slide meets the barrel, they both begin to move forward as one unit. As they move forward, the cam lug of the locking block is forced against the cam support block of the frame. This forced motion smoothly and gradually lifts the lugs of the locking block into the cutouts in the slide. Click here for figure 2-7.
2 Then, the bottom of the locking block reaches the top of the frame’s cam support block, and the locking lugs are fully engaged into the slide.
3 At this point, continued forward motion pushes the locking block plunger cam against the beveled portion of the locking block plunger, forcing the plunger away from the locking block. Click here for figure 2-8.
4 The flat rear area of the plunger protrudes from the rear of the barrel; at this point, the barrel and slide are locked up.
Firing
Two Methods Firing may be done either single or double action. Single action occurs when the hammer is already to the rear before the shooter pulls the trigger. Double action begins with the hammer at rest against the slide. When the shooter squeezes the trigger, the hammer first moves rearward before falling forward.
NOTE: The advantage of single action is that it makes for a shorter, crisper, and lighter trigger pull than double action.
Single Action Firing
The following table describes the process of single action firing.
Stage Single Action Description
1 As the shooter squeezes the trigger, it rotates around the trigger pin. The post of the trigger bar, engaged with the post hole in the upper part of the trigger, pulls the trigger bar forward. Click here for figure 2-9.
2 As the trigger bar is pulled forward, the trigger bar lug contacts the sear cross bar, pushing the sear forward. Click here for figure 2-10.
3 The sear rotates around the sear pin, compressing the sear spring and pulling the nose of the sear out of the hammer’s full cock notch. The shooter’s finger continues to travel rearward a short distance before stopping. Click here for figure 2-11.
4 The hammer strut compresses the mainspring as the sear nose cocks and holds the hammer. Without the sear engaging the hammer’s full cock notch, the mainspring expands against the hammer strut. Click here for figure 2-12.
5 The strut, resting in the lower rear of the hammer, forces the head of the hammer forward against the firing pin.
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Firing,
ContinuedDouble Action Firing
The following table describes the process of double action firing.
Stage Double Action Description
1 As the shooter squeezes the trigger, it rotates around the trigger pin. The post of the trigger bar, engaged with the post hole in the upper part of the trigger, pulls the trigger bar forward. Click here for figure 2-9.
2 The trigger bar lug engages the double action notch on the bottom of the hammer. As the trigger bar moves forward, the lug pulls against the double action notch of the hammer causing the hammer head to rotate away from the slide. Click here for figure 2-10.
3 As the hammer rotates rearward, the hammer strut moves down compressing the mainspring.
4 As the hammer continues to move to the rear and the half cock notch passes above the sear nose, the sear spring swings the sear in against the hub of the hammer. The sear is now ready to stop the hammer from falling should the shooter release the trigger before pulling it completely to the rear.
5 When the hammer has traveled far enough to the rear, the lug of the trigger bar contacts the crossbar on the sear, rotating the sear nose forward enough to clear the cock notches on the hammer.
6 The trigger, at this point, slips off the double action notch. The mainspring is now free to expand allowing the hammer head to travel forward.
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Firing,
ContinuedCompleting the Firing Process
The remainder of the firing cycle is the same for both single and double action. The following table describes the completion of the firing process.
Stage Description
1 During trigger pull, the disconnector arm of the trigger bar meets the lower arm hook of the firing pin block lever rotating the firing pin block lever counterclockwise around its pin. Click here for figure 2-13.
2 The upper arm of the lever lifts the firing pin block up out of the way of the firing pin before the hammer is released.
3 The head of the hammer coming forward strikes a sharp blow to the firing pin striker protruding from the rear of the slide.
4 The striker, being in line with the firing pin, moves forward against the rear of the firing pin and applies its forward energy to the firing pin.
5 The firing pin then strikes the primer of the cartridge.
6 The impact of the firing pin ignites the fast burning chemical in the primer.
7 The primer flash then ignites the propellant powder in the cartridge case.
8 Rapidly expanding gases from the burning powder force the bullet down the bore of the barrel and start recoil, completing the firing process.
Unlocking
Process The barrel needs to be locked for a short time to give the bullet time to leave the barrel. If the barrel were not locked, much of the projectile's energy would be lost to recoil before the projectile could leave the barrel.
Remember, during locking, pressure from the recoil spring holds the barrel and slide unit forward. The following table describes the unlocking process.
Stage Description
1 When the weapon fires, the barrel and slide move slightly rearward bringing the rear face of the locking block plunger into contact with the back wall of the locking block cavity within the frame.
2 The barrel and slide, still locked together, continue rearward.
3 The locking block begins to clear the rear of the cam support block.
As the locking block clears, the beveled portion of the locking block plunger forces the locking block down into the locking block cavity.
4 The locking lugs are withdrawn from the lug recesses in the slide;
the support lug on the barrel meets the rear wall of the locking block cavity, halting rearward movement of the barrel.
5 The slide, unlocked from the barrel, continues its rearward movement thus completing the unlocking process.