Repairing Winchester's Model 12 Shotguns
John M. Browning designed almost every firearm produced by Winchester over a 19 year period, so it is rather ironic that he had nothing to do with one of the company’s most famous shotguns, the Model 1912.
John M. Browning designed almost every firearm produced by Winchester over a 19 year period, so it is rather ironic that he had nothing to do with one of the company’s most famous shotguns, the Model 1912. That honor belongs to one T.C. Johnson.
From 1912 until 1980, more than 2 million of the Model 12 shotguns were produced in 12, 16, 20 and 28 gauges. Barrel lengths ranged from 26 to 30 inches. In recent years, U.S. Repeating Arms Co./Winchester has been exploring its long company history and has found that a lot of its famous products still draw interest today. That interest prompted the reintroduction of the Model 12. The gun is available only in 20 gauge.
The Model 12 Takedown Process
As far as takedown is concerned, this new Model 12 is virtually the same as its predecessor. Pull back on the forearm and visually inspect the chamber and magazine to make sure there are no shells in either. Push the magazine lock pin, located at the front end of the magazine tube, down as far as it will go. Use the longest protruding end of this pin as a lever to rotate the magazine tube 90 degrees toward the left side of the barrel, or clockwise. Hold the action slide handle while sliding the magazine tube toward the muzzle until the stop lug on the magazine tube hits the barrel band. Hold the receiver with your right hand and turn the receiver extension toward your chest 90 degrees clockwise. The extension and barrel can then be slipped forward and out of the front of the receiver.
Horizontally clamp the barrel and magazine assembly in your vise with padded jaws, inverting them as you do so that the magazine tube faces up. Push in on the magazine lock spring with a small blade screwdriver and pull the magazine lock pin up and out.
Two screws on the forward end secure the magazine plug to the tube. Before removing these screws, insert a slave pin into the hole where the magazine lock pin fits. I use one made from a brass rod that is 1/2 inch in diameter and 3 inches long, with one end turned down to 0.250 inch at a length of 11/2 inches. This pin keeps the magazine plug from launching forward from the tension of the magazine spring. #150-3 magna-tip bit fits these two magazine end cap screws well. Holding the magazine plug, ease it forward slowly after removing the slave pin until the magazine plug is free of the tube and the tension from the spring is gone. The magazine spring can now be removed from the tube. This spring may have a wooden dowel inside it that is used as a plug, which, depending on the length, limits the number of shells that can be loaded into the magazine. You will often find the ends of the magazine spring bent or crimped inward so that they won’t hinder the spring’s movement. The wooden dowel can be removed if necessary by bending the spring in the middle at a 90 degree angle.
Removing Barrel Band
The magazine/barrel band can be removed next by removing the right and left screws with a #340-3 magna-tip bit. Lift the band up and slide it forward off the muzzle end of the barrel, being careful not to lose the flat retaining spring. Insert the slave pin into the holes for the magazine lock pin and rotate the magazine tube 90 degrees counterclockwise. This will disengage the interrupted threads on the rear of the tube from the receiver and allow the tube to be moved forward and out of the receiver. The action slide is removed along with the magazine tube. A spanner wrench can be used to turn the action screw cap off the action slide. The cap can then be slipped off the front end of the magazine tube and over the stop lug. The action slide can also be pulled forward and off the threaded end of the magazine tube. Clamp the action bar in a padded vise and slide the forearm forward and away from the flange at the rear of the action slide. Up to this point, the magazine follower has been held inside the threaded end of the magazine tube by the shoulder. The follower can now be taken out the front end of the magazine tube. The inside of the magazine tube usually needs a liberal scrubbing with a brass brush and solvent. Use a brush one gauge higher than the bore size. For example, a 12-gauge shotgun magazine tube should be cleaned out with a 10-gauge bore brush followed by several dry patches. The action slide recoil spring, found on the rear of the magazine tube just behind the collar, can now be removed for replacement, if necessary.
Place the receiver in your padded vise, with the trigger guard down. Turn the barrel/receiver extension 90 degrees clockwise to disengage the threads from the receiver, then pull it forward and out the front of the receiver. There is an adjusting sleeve threaded onto the chamber end of the barrel in back of the receiver extension. The sleeve is adjustable, so, if the fit has become loose, a tighter joint between the extension and the receiver can be achieved.
If the fit is good, these parts can be cleaned or blued as is. The adjusting sleeve must be taken off to remove the receiver extension. Don’t remove the extension unless you are replacing it or the barrel.
Removing Trigger Guard
When removing the trigger guard, the hammer should be in the cocked or rearward position and the safety in the on position. Remove the trigger guard screw in back of the trigger bow with a #210-3 magna-tip bit. Grasp the trigger guard bow in one hand and tap on the side of the receiver with a rubber-faced hammer as you lift on the rear of the trigger guard. Tilt the rear of the trigger group first, then lift up and out. Removing the trigger group will give you access to the inside of the receiver. Make sure the breech bolt is forward, then use a small flat-blade screwdriver to push the ejector away from the bolt and free the front end of the ejector. Insert the screwdriver blade between the ejector and ejector spring, then lift the head of the ejector out the left side of the receiver. It will then drop into the receiver and can be removed. Inspect the ejector and spring to see that the ejector is not bent or the spring broken. The spring is staked onto the ejector at the round rear end and must be restaked if it is replaced.
The cartridge stop is held in place by its front edge and a pivot stud in a recess on the left side of the receiver. Remove the cartridge stop, look it over for any irregularities, and replace if necessary.
The breech bolt is held in the receiver by a breech bolt retaining lever that engages a groove in the left inner side of the receiver. With the small flat-blade screwdriver, push the rear of the retaining lever up against the breech bolt. The bolt can now be pushed to the rear of the receiver. As you do this, tilt the rear of the bolt up and out of the receiver. The receiver should now be devoid of internal parts and can be cleaned with a good solvent.
Lay the bolt body left side up on your bench. Using a #150-2 magna-tip bit, remove the firing pin retractor screw. Lift out the retractor and then the retractor spring. If the retractor is bent or has heavy burrs, it may impair the retraction of the firing pin in the breech bolt. Remove the burrs and straighten the retractor or replace it if these conditions exist. You may need to invert the bolt and tap the top of it on your bench to get the spring to come out of its hole if there is an accumulation of debris around it. The firing pin should now come out the rear of the bolt. When a firing pin fails, it usually loses the very tip or section that comes out the face of the breech bolt. By placing the top of the bolt down on your bench block, you can gain access to the left extractor pivot pin. Drift this pin down and out with a 1/16-inch punch, holding the extractor in place as you remove the punch so as not to lose the extractor spring. Place the bolt down on its left side with the right extractor up. The right extractor is activated by a spring and plunger in a recess on the right side of the bolt. For removal of this type of plunger and extractor, I use an old screwdriver that has been heated and bent into a hook that will hold the plunger back while the extractor is removed. Remove the plunger and spring, then use a pipe cleaner and solvent to clean out the parts’ recess.
While the bottom of the bolt is facing up, the bolt retaining lever pin can be drifted down and out with a 1/16-inch punch. The bolt retaining lever can now be carefully pried out of its recess in the left side of the bolt. You should now be left with a bolt body that can be scrubbed with a good cleansing solvent and then dried with compressed air.
If the breech bolt does not lock, or is hard to close, see how the extractors are fitting into the chamber ring. The outside faces of the extractors may need to be dressed down with a file for clearance or the extractors may need replacement.
Clamp the trigger guard bow in your padded vise, with the top of the trigger group up and the right side facing toward you. Use a #240-3 magna-tip bit to remove the carrier screw. This screw has a left hand thread, so be sure to turn the screw clockwise for removal to avoid damaging the screw. Remove the screw and lift the carrier out of the trigger guard.
Push the front end of the cartridge guide outward and swing it down. This will free the spring lug end and allow the carrier spring to be removed from the lug on the cartridge guide and carrier. Check out the cartridge guide spring to make sure it is not deformed or broken.
On guns made before 1957, in the serial number range below 1650000, the cartridge carrier was manufactured differently, so some will have a cartridge guide rivet and some will not. If you need to remove the cartridge guide rivet, place the cartridge guide on a block so that the rivet hole overhangs the edge. With a 3/32-inch punch, drift the rivet down and out. If the guide is to be replaced, the rivet will need to be restaked in the new hole in the carrier at two spots other than the previous staking points.
To remove the carrier plunger, spring and screw, place the carrier on a flat surface with the carrier screw head up. Use a #210-2 magna-tip bit to turn this screw counterclockwise for removal. This screw has been staked into place by peening over metal into the ends of the screw slot, so it may start turning hard. Once the screw has been removed, the spring and plunger can be taken out and cleaned or replaced.
Pull the trigger while holding the hammer, then ease the hammer forward. Place the trigger guard down on a bench block so that the hammer pin is over one of the holes in the block. Drive out the hammer pin with a 1/8-inch punch, leaving the punch in place temporarily. This will contain the other parts and prevent them from popping out until you are ready to remove them. Grasp the trigger guard in your left hand, holding the hammer with the fingers of your left hand. Remove the 1/8-inch drift and ease the hammer out, slowly relieving the tension on the hammer spring. The spring can now be removed from the spring guide on the hammer. Replace it if it has become weak from storage in the cocked position. If it is necessary to remove the hammer spring guide rod, place the hammer over an appropriately sized hole on your bench block and drift out the retaining pin with a 3/32-inch punch. This pin is also staked in place to prevent side-to-side movement. When replacing the pin, make sure the staking is done again to prevent the hammer spring guide pin from moving sideways.
To remove the trigger, lay the trigger guard on a flat surface with the right side down. Insert a 3/32-inch punch into the trigger pin hole and drive out the pin. Leave the punch temporarily in place. Hold the trigger guard in your left hand, with the thumb resting on the slot that holds the trigger, and remove the drift. Ease the trigger up and out of the trigger guard. Watch to see that the trigger return coil spring drops out of the recess hole in the trigger guard.
To remove the action slide lock, lay the trigger guard down on a flat surface with the left side down. Insert a #150-2 magna-tip bit through the hole in the right side of the guard just above the trigger bow until it engages the slot of the action slide pivot screw. Turn the screw counterclockwise to remove it. You may have to tap the guard on your bench to get the screw to fall out if it didn’t stay on the magna-tip bit. The action slide lock can now be lifted up and out of its slot in the side of the guard. The two springs that activate the action slide lock may need to be replaced because of weakness or breakage.
Action Slide Lock
If the action slide lock does not function properly, the activating springs may be worn or broken, so they should be replaced. You should also check to see that the hammer pin has not been driven in too far, thus interfering with the slide lock’s function. If the cartridge cut-off is bent, it could cause action slide lock failure.
To remove the safety, make sure it is in the “on” position with the red band not showing. Insert a 1/16-inch punch into the hole in the left end of the inverted safety, then turn the safety 90 degrees toward the front of the trigger guard. This will disengage the activating detent plunger and spring. Remove the punch and push the safety toward the left until the end is flush with the guard. The safety plunger and plunger spring will now pop up and out of their hole in the trigger guard. Check the spring to make sure it is not bent or weak, and examine the plunger tip for any flatness that would cause it not to work properly. Replace the spring or plunger if you have any doubts of their condition.
The buttstock will have to come off if the shotgun needs blueing or the stock requires refinishing. It’s easier to flush debris out of the receiver if you don’t have to worry about getting solvent on the wood. Remove the buttplate or recoil pad to expose the cavity in the rear end of the stock and give access to the stock bolt. Tighten the receiver in your padded-jaw vise and remove the stock bolt with a Bonanza #6 screwdriver.