the Single Action Revolver
Dec 9, 2021 // By:admin // No Comment
Let’s look at a Colt Single Action Army Revolver (Colt SAA)
As always, begin by confirming that the revolver is unloaded. With a Colt SAA, there is enough space between the rear of the cylinder and the recoil shield to permit a check for cartridges before adjusting the hammer. You can also check the cylinder for drag lines found on the exterior of the cylinder caused by unwanted rubbing or contact against the cylinder during rotation normally caused by dirt or debris.
Step 2: The Hammer
Time to introduce the “Four Clicks”.
There are four distinctive sounds made when drawing back the hammer of the gun from the fully lowered position to the fully cocked position. If working properly, the first click should be heard when the safety notch on the hammer engages, the second click when the half-cock notch engages, the third when the cylinder stop pops up to engage the notches (note: the stop pops up before the cylinder has completed its rotation, hence why partial drag lines are found even on otherwise nice Single Action Army revolvers), and the fourth when the hammer reaches full cock and the stop drops into the appropriate cylinder notch near simultaneously.
All three lock spots prevent the hammer from going forward.
only the last lock spot (fully cocked) will even allow the hammer to go forward, and only when the trigger release it.
Failure to produce an audible click at each stop, too many clicks, or other noises produced during cocking are all signs of possible damage. While the hammer check is performed, be mindful of the mainspring; looseness or excessive resistance both indicate trouble, the former from a badly worn, broken, or absent mainspring, and the latter a mainspring that is losing ductility, which could potentially become brittle and break during operation.
The safety notch, which produces the first click, is a short distance back from the resting position of the hammer. The design is meant to keep the firing pin from protruding through the recoil shield and potentially contacting the primer of a cartridge. While, in theory, a live round could be kept under the hammer set on the safety notch, the best practice for revolvers not equipped with a transfer bar or similar safety device is to leave an empty chamber in line with the hammer until shooting is just about to begin. When the hammer is on the safety notch, three things should be true:
- The firing pin should not be visible through the recoil shield when viewed from the side with a good light source.
- The hammer should not move if the trigger is pulled.
- The cylinder stop should still be engaged to the cylinder, preventing rotation.
Failure on any of these points indicates that something is wrong. Point one and point two would both suggest damage, while the third would suggest that the safety notch is completely gone, and the first click was actually the half-cock.
Click number two, the half cock notch, is about halfway between resting and full cock. This is the loading position for the SAA, permitting access to each chamber in turn without having to fiddle with the hammer during the process. When checking the half cock, note the following:
- When pressure is let off the hammer, it should not travel a significant distance forward.
- The hammer should not move if the trigger is pulled.
- The cylinder stop should be disengaged and the cylinder free to rotate in a clockwise manner as viewed from the rear.
Much like with the safety notch, failure at any of these points indicate notable wear or a flat out loss of function of the notch. While a failure in the safety notch is more or less made irrelevant by best handling practices, a failure in the half cock notch is more ominous, as it can make the loading process complicated or even dangerous, increasing the chances of a negligent discharge. A Single Action Army with a disordered half cock notch can be physically capable of firing, but is not recommend.
Click number three, the cylinder stop, happens shortly before the full cock notch. At this stage, the hammer has not engaged; if released, it will drop back to the half cock (if the trigger is not being held down), the safety notch (if the trigger is not held and the half cock is excessively worn or damaged), or all the way to the resting position (if the trigger is being pulled, or both notches are damaged). Letting the hammer down in a harsh or uncontrolled fashion is sometimes a cause of excessively worn or damaged notches and should be avoided.
The final click is actually two clicks at once, as the cylinder stop engages the cylinder at about the same time as the full cock notch engages. Being able to hear a “fifth click” suggests that one or the other has gone a bit out of order. With the full cock, note the following:
- The hammer should be as close as possible to the maximum possible rearward travel, with no significant “let down” once thumb pressure is removed.
- The cylinder stop should be fully engaged, possibly with a small amount of “play” in the cylinder, but not permitting any significant rotation.
- When the trigger is pulled, it should move without an excess of force, and the hammer should drop cleanly to the resting position without friction or interference from the other notches, and the cylinder stop should continue to be engaged.
Failure at this stage could indicate the handgun is non functioning, or is one that is dangerous to shoot. A hammer that hangs up could result in a later than expected discharge, and a cylinder that fails to remain properly locked could cause a misfire as the hammer fails to hit a primer. Even worse, it could hit the primer while the bullet is positioned to strike the edge of the barrel throat instead of straight on, causing the gun to explode in the shooter’s hand.
Step 3: The Cylinder
Once the hammer is checked, the cylinder comes next. On a well made revolver, the cylinder is a subtle yet critical demonstration of precision engineering. The proper engagement of the cylinder to the working parts of the frame is a complete necessity in terms of revolver function.
In order to make sure the cylinder hasn’t suffered wear or alteration that would affect function, rest a thumb of the off hand against the side of the cylinder, applying light pressure, and then ease the hammer slowly back to full cock. Once the revolver is cocked, try moving the cylinder clockwise and counter-clockwise with said thumb. The cylinder should remain locked, no new clicks should be audible, and there should not be an excess of play in the cylinder. Gently ease the hammer down, and repeat the process five more times, each time maintaining light thumb pressure and slowly cocking the hammer. An audible click on the clockwise rotation indicates that the cylinder didn’t fully advance to the appropriate stop. Continued rotation clockwise indicates that the cylinder rotated too far, and the stop failed to engage the appropriate notch.
A failure in these tests on one or two chambers suggests that the problem is with the cylinder, with an individual stop notch or tooth on the sprocket experiencing wear or damage, but a failure on all chambers suggests that the problem is in the guts of the revolver instead.