This will work with the 336, .444 also

The only tools needed is a set of gunsmith screwdrivers. As you can see I use a Leatherman tool with bits. It works, but a proper set of screwdrivers is much better. A piece of rag cloth on your workbench saves the rifle from scratches and stops screws and small parts rolling to the floor.
1. Make sure the rifle is unloaded and the magazine empty.

2. Make sure the rifle is unloaded and the magazine empty once more.

3. Cock the hammer (33) and open the action about 1/3.
4. Remove the lever screw (24) and the lever (20):

5. Remove the breech bolt (6) and the ejector (18):

The barrel may now be cleaned from the chamber end.

Further disassembly for thorough cleaning or maintenance:
6. Remove the tang screw (68):

7. Pull back the butt stock (10):

8. Lower the hammer (33). This is a bit complicated. With a grip as shown on the photo: Push in the trigger safety block (74), pull the trigger and lower the hammer.

9. Remove the main spring (35) by sliding the hammer spring adjusting plate (36) sideways out of the notch in the trigger guard plate (92):

10. Remove the hammer screw (34):

11. Remove the trigger plate support screw (73) on the left side of the receiver, just over the lever screw.

12. Remove the trigger plate screw (72) in front of the trigger plate:

13. Pull down the trigger plate (92):

14. Remove the locking bolt (44):

15. Remove the hammer (33):

16. Remove the carrier screw (15), on the right side of the receiver, close by the safety:

17. Remove the carrier (11):

18. Remove the loading spring screw (43) and the loading spring (42):

19. Remove the forearm tip tenon screws (32). Leave the forearm tip (30) in place till the magazine tube is removed:

20. Remove the magazine tube plug screw (48) leaving the magazine tube in place:

22. Ease the magazine tube away from the barrel holding the magazine tube plug still in the tube (47):

23. Remove the magazine tube plug (47) trying to avoid magazine plug and spring (49) going out in orbit. Remove the plug with your right hand and keep control of the spring with your left:

24. Move the forearm tip (30) a bit towards the front end of the magazine tube (45) and remove the forearm from the barrel in down and forward direction:

25. Remove the forearm (29), magazine tube (45) and magazine tube follower (46):

26. Turn the magazine tube with the "hunch" upwards and slide the magazine tube out of the forearm.

Then everything is disassembeled for cleaning and maintenance. Further dissasembly is seldom neccessary and requires a bit more tools.

Put a light coat of oil on all parts prior to reassembly. On moving parts a thin coat of Gunslick, or similar graphite lube, makes the action cycle smoother.
Dont tighten the screws all the way until everything is back together.

1. Keep the loading spring (42) in place with your left hand and turn in the loading spring screw (43) with your right. Applying a drop of Loctite on this screw before assembly is a good idea. If this screw turn loose the loading spring may cause a jam when cycling the action.

2. Put the carrier (11) in place, and secure it with the carrier screw (15):

3. Put the locking bolt (44) in place:

4. Put the trigger plate (92) in place and secure it with the trigger plate support screw (73) and the trigger plate screw (72):

5. Insert the hammer (33) through the clearance slot in the top of the receiver:

6. Put the hammer in place and secure it with the hammer screw (34):

7. Put the hammer spring (35) on the hammer strut (40) and put the hammer spring adjusting plate in place (36). Make sure that the hammer is not cocked. Put the plate in the notch in the triggerguard, make sure that the hammer strut goes trough the hole in the plate. Compress the spring by using the plate as a lever (!), forcing the plate forward / downward untill it goes under the tang. Then slide the plate in to the center of the action:

8. Slide the buttstock (10) in place and secure it with the tang screw (68).

9. Slide the magazine tube (45) in place ("hunch" to the left) in the forearm (29) and slide the forearm tip (30) on to the magazine tube. Place the rear end of the forearm / magazine tube against the receiver in a slight angle to the barrel. Then put the forearm / tube in place along the barrel. When the magazine tube stud (50) starts to enter the hole in the front end of the tube insert the follower (46) (hollow end forward), spring (49) and plug (47). Use your right hand to feed the spring into the tube and secure the spring with your left when shifting grip with your right. When the spring is completley inside the tube, secure it with your left hand and put the plug in place with your right. (Often the procedure is interupted here by a "spiong" followed by heavy cursing as the plug and spring leaves the tube...) Ease the tube with plug on to the strut and turn the magazine tube plug screw (48) in, dont tighten it yet. Put the forearm tip (30) precisly in place and turn in the forearm tip tenon screws (32). Then tighten the magazine tube plug screw (48).

10. Put the ejector (18), breech bolt (6) and lever (20) in place and turn in the lever screw (24).

11. Finally tighten all screws to desired torqe.

Cycle the action and check that everything moves smoothly. Load the magazine with a couple of dummys (I use a pair of A-ZOOM Action Proving Dummy with Snap Cap 45-70, Midway #460024) and check that feeding, extraction and ejection functions like it should.

Thanks to Sure-Shot and his post It inspired me to take the photos and write this guide.
Thanks to Marlin / Brownell for the parts drawing.

Please feel free to comment any errors, both technical and writing (English is not my native tounge).