Someone recently asked about the availability of a tutorial on the old style Marlin tube magazines like are found on the Models 18, 20, 29, 38, etc. I have a Model 20 that the dovetailed base for the magazine attachment screw was loose in the barrel dovetail. I also have a spare Model 38 magazine assembly that was salvaged from a parts gun and in need of disassembling and a good cleaning. So I thought I would put together a few pics of the procedure I use when disassembling and reassembling these types of magazines.
Here is my little Model 20...
Here is the outer magazine slid forward and locked into place...the screw that attaches the magazine assembly to the barrel is also visible.
Back the attachment screw out...raise the magazine assembly away from the barrel as you do so...keep the head of the screw slightly exposed above the outer magazine tube. This will keep everything locked into place.
Here is the magazine assembly removed from the gun. The attachment screw is keeping things from flying apart.
While I'm here, I'll show you how I tightened the dovetailed base in the dovetail...I used a center punch to dimple the metal next to the dovetail and tighten things up. Magazine assembly will hide this when reinstalled. Other methods will work also.
Here is the old magazine assembly from the model 38...longer than the 20 but otherwise the same.
I use a punch to push the screw out...the punch takes the place of the screw and holds things together. I can then pull the punch back enough to clear the outer tube and allow the inner tube and attached inner latch plug to be lowered all the way back down.
We can now drive out the pin that holds the magazine latch assembly in place. Once the pin is out, the latch assembly can be removed. Note before removing which side the latch is on in relation to the outer magazine tube.
Magazine latch removed, latch plug, and spring..
Magazine assembly disassembled..
Note that the magazine plug or follower has an "ear" that fits in the small groove in the inner magazine tube.
Also note that the outer magazine tube has a tab that will catch behind the ramped notch cut in the inner magazine tube. This is what locks the outer tube into place when it is drawn out to insert cartridges. If your outer magazine tube will not stay locked in place, you can take a file and carefully file the notch...careful...the tube is thin here. If your outer tube tab is broken, you have a problem.
Note that when the inner tube is inserted into the outer tube that there is an impressed tab in the outer tube that slides in the groove cut in the inner tube.
Note that the spring loaded latch mechanism has a hole that must be aligned with the hole in the outer magazine plug when reinstalling both into end of the outer magazine tube.
When ready to begin reassembly, insert the magazine follower into the inner tube as shown...be sure to align "ear" with slot.
With the follower pushed a short distance into the inner tube, slide the inner tube into the outer tube from latch end...be sure to align slot in inner tube with tab in outer tube. Push inner tube in until the end sticks out as shown below:
Here is my little Model 20...
Here is the outer magazine slid forward and locked into place...the screw that attaches the magazine assembly to the barrel is also visible.
Back the attachment screw out...raise the magazine assembly away from the barrel as you do so...keep the head of the screw slightly exposed above the outer magazine tube. This will keep everything locked into place.
Here is the magazine assembly removed from the gun. The attachment screw is keeping things from flying apart.
While I'm here, I'll show you how I tightened the dovetailed base in the dovetail...I used a center punch to dimple the metal next to the dovetail and tighten things up. Magazine assembly will hide this when reinstalled. Other methods will work also.
Here is the old magazine assembly from the model 38...longer than the 20 but otherwise the same.
I use a punch to push the screw out...the punch takes the place of the screw and holds things together. I can then pull the punch back enough to clear the outer tube and allow the inner tube and attached inner latch plug to be lowered all the way back down.
We can now drive out the pin that holds the magazine latch assembly in place. Once the pin is out, the latch assembly can be removed. Note before removing which side the latch is on in relation to the outer magazine tube.
Magazine latch removed, latch plug, and spring..
Magazine assembly disassembled..
Note that the magazine plug or follower has an "ear" that fits in the small groove in the inner magazine tube.
Also note that the outer magazine tube has a tab that will catch behind the ramped notch cut in the inner magazine tube. This is what locks the outer tube into place when it is drawn out to insert cartridges. If your outer magazine tube will not stay locked in place, you can take a file and carefully file the notch...careful...the tube is thin here. If your outer tube tab is broken, you have a problem.
Note that when the inner tube is inserted into the outer tube that there is an impressed tab in the outer tube that slides in the groove cut in the inner tube.
Note that the spring loaded latch mechanism has a hole that must be aligned with the hole in the outer magazine plug when reinstalling both into end of the outer magazine tube.
When ready to begin reassembly, insert the magazine follower into the inner tube as shown...be sure to align "ear" with slot.
With the follower pushed a short distance into the inner tube, slide the inner tube into the outer tube from latch end...be sure to align slot in inner tube with tab in outer tube. Push inner tube in until the end sticks out as shown below: