Taking down and assembling a Ruger Mark III .22 caliber pistol for cleaning is not difficult, if done in the proper steps. If not done properly, it can be frustrating. If I let a long time pass without doing it, I forget how to do it.
Items needed are: a Mark III pistol, a paper clip, as soft plastic hammer, and a needle nose plier or a small screwdriver.
If I am not mistaken, the procedure is the same for a Ruger Mark II pistol.
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Step 1: Safety First
Remove the magazine. The magazine release button is under my left thumb. Hold it down and pull the magazine from the bottom of the pistol handle.
I am working on newsprint to protect the table surface and to protect the gun parts.
Step 2: Safety Continued
Pull the bolt (rear end of the barrel) back about 3/8 of an inch and look into the receiver to be certain there is no bullet in the chamber. This pistol has no bullet. See the yellow arrow.
The Mark III has a thin wedge on the left side of the receiver that protrudes from the side of the gun if a bullet is in the chamber, but I prefer to look, anyway. A red dot is visible on the wedge when a bullet is in the chamber.
If the pistol cocks when you pull back the bolt, pull the trigger*, or you will not be able to remove a vital part in the next steps. If the bolt does not return to its closed position, find and press the bolt (or slide) release at the top of the left side handle. Then pull the trigger, if you have not already released it. You may need to insert an empty magazine to accomplish this. Remove the empty magazine when the pistol is no longer cocked.
*Note: While dry firing a firearm is very much discouraged, the Ruger's manual says it is no problem to dry fire this gun if the internal lock is disengaged, the safety is in the F or "off" position, and the firing pin stop has not been removed from the bolt. See the manual for further details on any of these items.
Step 3: Open the Mainspring Housing
The mainspring housing is located in the pistol's handle. It's latch is the point of metal in the oval indentation. See the tip of the yellow arrow.
Step 4: Open the Latch
Hook the round end of a paper clip over the mainspring latch and pull toward yourself. It pulls a little hard. Use the thin nose pliers to pull the paper clip.
Step 5: Latch Released
Here you see the mainspring latch fully extended (yellow arrow). Notice the red arrow. This points to part of the mainspring bolt stop assembly as it begins to protrude from the pistol handle after the latch is released.
Step 6: Remove the Bolt Retainer
Grasp the whole mainspring bolt stop assembly as shown and pull it downward as shown by the yellow arrow to remove it from the pistol. It comes out fairly easily, but will require a little force.
Step 7: Remove the Bolt
Pull the bolt out of the pistol in the direction shown by the yellow arrow. If it binds and will not come out, the hammer or hammer strut may have moved to make an obstruction. See step 8 to resolve this.
Step 8: Clearing the Way
The hammer and hammer strut tend to move around as the pistol is held at different angles. This can obstruct the removal of the bolt from the barrel.
The view in the photo is into the back of the pistol's handle. The yellow arrows identify the parts. Much of the hammer is in shadow. When the hammer moves, the hammer strut easily falls forward of the crosspin. Push the hammer in the direction of the red arrow. The tips of the needle nose pliers or a small screwdriver work well for this. Point the barrel of the gun upward so the hammer strut can fall toward the rear of the gun out from in front of the crosspin (as shown in the photo). Now the bolt should be free to slide out if it was not before.
Step 9: Remove the Barrel From the Pistol Frame
Use a soft plastic hammer to remove the barrel from the pistol frame. Pound in the direction of the yellow arrow. Pound in the area marked by the green line. Pounding in the area marked by the red line means you are pounding on the pistol frame, which will not remove the barrel from the frame.
When the barrel releases from the frame, it will do so quickly and will fall. Grasp it between your knees or hold it low over the table to prevent damaging anything.
Step 10: Position the Hammer Before Installing the Barrel
The photo shows the top of the pistol frame. The yellow arrow points to the hammer. It should be pushed down so it is flat and level with the top of the pistol frame.
The safety should be set to its lower position so the "F" shows in the opening. See the red arrow for the location of the safety.
Step 11: Pound the Barrel Onto the Frame
Use the soft plastic hammer to pound the barrel back onto the pistol frame. There are two wedge-shaped catches between the frame and the barrel. Begin with the barrel a quarter inch or so forward of where it will be when seated so the catches engage. Pound fairly forcefully.
Step 12: Align Barrel and Frame
It is critical that the rear end of the barrel is even with the rear of the pistol frame. When pounding the barrel back onto the frame in the previous step, the barrel probably went a little farther toward the rear of the frame than is desirable. Pound so the hammer face overlaps both the rear end of the frame and the rear end of the barrel to make them even with one another. The reason why can be seen in the next step.
Step 13: Hole Alignment
The holes in the frame and the barrel for the bolt retainer pin must align or the bolt retainer pin will not go into place. The bright metal in the hole is from the pistol's bolt and this piece has some freedom of movement. It is not a problem. Hole alignment is the reason for the previous step.
Step 14: Insert the Bolt
The factory manual warns against damage to the firing pin if the bolt is installed without the firing pin stop. This is a pin that runs from one side of the bolt to the other. I have not yet disassembled the bolt. Unless you do, this will not be a problem to watch. The bolt will not go into the barrel upside down. There is only one way it fits.
If the bolt does not slide into the barrel, wiggle it a little. If anything obstructs it, check step 8. Turn the pistol handle up and see that the hammer and the hammer strut are not in the way.
Step 15: Install the Bolt Retainer Pin
Hold the gun with the barrel pointing to the floor. Check to be sure the hammer strut is above the crosspin, not forward of it, that is below it. Insert the bolt retaining pin into the holes for it and push on it until fully seated. (Notice how the rounded end of the bolt retainer pin extends above the top surface of the barrel.) Also, place an empty magazine into the pistol's handle. Snap it into place.
Step 16: Finish the Process
Now hold the pistol with the barrel pointing upward. Pull and hold the trigger. Rotate the mainspring housing stop assembly back into the handle. Close the latch. This should all go smoothly. If the mainspring housing stop assembly does not swing easily back into the pistol handle, the hammer or the hammer strut may not be properly positioned. See step 8 again. Close the latch when all is as it should be.
Any problems I have had in the assembly of the pistol or in its operation have been due to the hammer or the hammer strut being out of their proper place.
Finally, wipe away any fingerprint oil you might have left on the gun.