TUNING MARLIN LEVER ACTIONS
By Lionel Roach, aka JONAH
Editorial note: This is information only about what a few cowboys found worked
for them. If you do not feel comfortable working on your gun and assuming
liability, please go to a good gunsmith and let them tune your gun. Those involved in Cowboy
Action Shooting (CAS) have never had it so good when it comes to firearms and
related equipment.  While some
manufacturers were slow to climb aboard the bandwagon, others listened to what
shooters wanted and responded.  Marlin
Firearms worked with shooters and gave us the Model 1894 and the Model
1895.  An informal count of the number
of Marlin Model 1894's at any CAS shoot will show how popular the Marlin has
become. At shoots that I've attended, at least fifty
to sixty percent of the rifles being used will be Marlins. A sideline industry has emerged to tune and modify the firearms used in CAS,
but individual owners can
perform many of the tune up procedures themselves. There are some parts
that are best left to the professionals or
at least advanced amateurs such as working on sears and hammer notches.
However, with a little bit of time and minor
tools, the average owner can do a good job of smoothing up their action. The following procedures apply
to the Models 1894, 1895 and the 336. For additional instructions
covering lever action rifles, Accurizing
The Factory Rifle, by M. L. McPherson, is the best book I have read and I
highly recommend it.
Those involved in Cowboy Action Shooting (CAS) have never had it so good when it comes to firearms and related equipment.  While some manufacturers were slow to climb aboard the bandwagon, others listened to what shooters wanted and responded.  Marlin Firearms worked with shooters and gave us the Model 1894 and the Model 1895.  An informal count of the number of Marlin Model 1894's at any CAS shoot will show how popular the Marlin has become. At shoots that I've attended, at least fifty to sixty percent of the rifles being used will be Marlins.
A sideline industry has emerged to tune and modify the firearms used in CAS, but individual owners can perform many of the tune up procedures themselves. There are some parts that are best left to the professionals or at least advanced amateurs such as working on sears and hammer notches. However, with a little bit of time and minor tools, the average owner can do a good job of smoothing up their action.
The following procedures apply to the Models 1894, 1895 and the 336. For additional instructions covering lever action rifles, Accurizing The Factory Rifle, by M. L. McPherson, is the best book I have read and I highly recommend it.TOOLS AND EQUIPMENT
Before you attempt to do any work on your rifle, get a good set of gunsmith screwdrivers. Do not try to use your hardware store special screwdrivers.  Burred screw heads will result from use of standard screwdrivers. Gunsmith screwdrivers are available from Lyman, Chapman and others.  If not available locally, gunsmith screwdrivers can be ordered from Midway, Brownell's and others.
Additional equipment required will consist of a sheet each of 400 and 600 grit wet or dry paper. Nice to have would be a few small hones, but the wet or dry paper will get you by. When we begin to work on the hammer, a belt sander or bench grinder will be required for part of the procedure.
INSPECTION To see the Marlin parts diagram
Before beginning with the actual tune up, cycle the action slowly and try to determine where in the cycle roughness is felt.  The areas to pay attention to are the lever plunger that holds the lever closed, the carrier lifting up, the bolt sliding in the receiver and the bolt passing over the hammer.  All of these areas will most likely require attention and will be addressed during the tune up. Unless you have been shooting your rifle a great deal, I recommend that you cycle the lever several hundred times prior to beginning any work. This will accomplish two things.  First, it may smooth out any burrs that are there. Second, it will leave burnish marks on the areas that are in contact so you can identify those areas needing work. If you reload, make up several dummy rounds, without primer. Cycle these dummy rounds through the action.  By doing so, you may find areas inside the action where brass has rubbed off on the parts. This will give you an excellent idea of where to spend time polishing those parts. Before disassembly, slowly open the action and observe the point at which the hammer comes to full cock.  On my Marlin 1894 and 1895, the bolt depressed the hammer another 3/32" after reaching full cock.  I have observed the same amount of over travel on other Marlins. We will address this when we work on the hammer.DISSASEMBLY
Begin disassembly by opening the action about half way and remove the lever screw, the lever, the bolt and the ejector.  Remove the rear tang screw and slide the stock of the rear off the action. Lower the hammer by depressing the trigger safety block. Hold the hammer under the thumb, depress the trigger and let the hammer go forward against the frame. Remove the hammer spring by sliding the hammer spring plate to the left side and then remove the hammer spring. Remove the hammer pivot screw and remove the hammer through the clearance slot by rotating it upward.  Turn the rifle over and remove the trigger guard plate support screw from the left side of the action.  Then remove the trigger guard plate screw from the bottom.  This is the screw just in front of the carrier leg slot. Note that this screw is longer than the previous screw. Lift up on the lower tang and remove the trigger guard plate.  Remove the locking bolt from the bottom of the action. Remove the carrier screw from the right side of the action. The carrier will now fall out of the bottom of the action.  There is no need to remove the loading gate screw.  The action is now dissembled as far as required for the tune up.LEVER
Inspect the lever for any burrs on the end where it bears on the carrier and bolt.  Burnish marks on the end will show where it is in contact with the carrier and bolt. Lay a 2" by 2" piece of 400 grit wet or dry paper on a flat surface near the edge of your workbench. Place one side of the lever flat on the paper and polish the side.  Then flip it over and polish the other side.  Polish off any burrs found on the two narrow edges. Stay clear of any of the areas that will be outside of the action so that you don't remove any bluing.  This is a polish only operation.  Do not remove metal or change the shape of the end of the lever.
Editor's note: Also refer to the Marlin 94 Fix. It describes a fix for preventing a timing problem due to wear of the excellent Marlin action. Fixing the Marlin JAM
The finger lever plunger will need to be polished and the spring tension reduced. With a small punch or nail with the end ground flat, remove the plunger pin.  The plunger is under tension, so be careful and don't let the plunger and spring jump out and get lost.  Hold a finger over the plunger end or put a small rag over it to contain it. Using the 400 and 600-grit paper, polish the two bevels on the end of the plunger.  Check the shank of the plunger and remove any burrs you may find. Place the spring back on the plunger and insert it into the hole in the lever.  While looking through the pin hole, push the plunger in until the hole is clear. Continue pushing in the plunger until it is flush or nearly so.  This will give you a good idea of the amount of the spring that can be removed. In my rifles, I removed two coils by cutting them off with a good pair of side cutters. I recommend that you only cut one coil at a time and then try the plunger in the lever for tension.  The plunger must have enough tension to fully extend and lock the lever in the closed position. If you remove too much of the spring, you may find that the lever will unlock when you fire the rifle with heavy recoiling loads.  Since your fingers are through the lever when firing, this is not a dangerous occurrence. However, it is annoying.TRIGGER GUARD ASSEMBLY
Unless you are experienced in working on sear surfaces, I recommend that you leave the trigger and sear alone.
Take the trigger plate in your hand and look down into it from the top side. You will see the trigger block safety spring. This spring also bears on the rear of the trigger. Using a small screwdriver under the short leg, the one bearing on top of the trigger safety block, pry up on the spring approximately 1/8".  You want to bend this leg upward enough to relieve tension on the trigger safety block. Don't try to get all the bend in one try, but bend it up a little, try the trigger block safety for tension by pushing it up from the bottom behind the trigger. Continue bending and trying until you can easily move the safety block up with your finger.  Leave enough tension so that the safety block always returns to it's down position.
Now look at the long leg of the spring where it bears on the rear of the trigger. Pry it up a little at a time to relieve some tension on the trigger.  Be careful and don't kink the spring.  You are only trying to relieve some of the tension.  It is better to error on the safe side rather than having to buy a new spring.
Some people feel that the floppy two-piece trigger/sear in the Marlin is undesirable. There are after market one-piece triggers available to replace the Marlin trigger. These replacement triggers are also advertised to reduce the trigger pull weight and all the comments I have seen regarding these triggers has been positive.
Check for any burrs and polish the sides and any burnished areas.  Do not remove any metal or change the shape.BREECH BOLT
Place the bolt back in the action and slowly slide it back and forth. It should move smoothly through out its length. Check for any burrs on the bolt and in the receiver and polish them out if you find any. Pay attention to the slot in the side of the bolt where the ejector rides and carefully polish the slot's sides and bottom. Wrapping a small piece of the 600-grit paper around a narrow file or Popsicle stick easily does this. Carefully polish the cam on the bottom of the bolt where it rides over the hammer nose. Do not reduce the height of the cam. Polish it only.
McPherson's gives detailed instruction on how to narrow this cam to reduce the friction as the bolt rides over the hammer.  This modification, in my opinion, is not for the faint of heart and should only be attempted by the advanced amateur or professional gunsmith. Bolts are not cheap should you have to replace it.
Like the objection to the two-piece trigger/sear, some object to the two-piece firing pin. Theory is that the two-piece pin requires more force from the hammer to fire the primer, especially when the hammer spring has been reduced.  After market one-piece firing pins are also available. In his book, McPherson details how to modify the existing firing pin to lighten it so I will leave it at that.HAMMER & HAMMER SPRING
Remove ¾ of a coil from each end of the hammer spring.  If you use a grinder to do this, do not get the spring too hot to hold or allow the spring to change color.  Go slowly and grind the cut off end flat like it was done at the factory. If you do not have a grinder, use a triangular file to file a groove in the coil and break the end off.  Then file it flat.  A Dremel tool with a cutoff blade will also work to remove the ¾ coil. In all three cases, do not nick the adjacent coil as this will set up a weak spot for future breakage.  The hammer spring, due to its barrel shape, goes away very quickly. Should you remove too much, you will find that it will not reliably, maybe not at all, provide enough force to fire a primer.  If this occurs, and you do not have a spare spring, do not despair. Locate, in your parts drawer or at the local hardware store, some small, thin washers that will just freely slip over the hammer strut. Place one on each of end of the spring and try to fire a primer in an empty case. One washer on each end will most likely provide enough power to fire a primer.
Remember the 3/32" hammer over travel referred to above? Some of this can be removed by grinding the nose of the hammer down using a belt sander or fine grinding wheel.  If you feel uneasy about removing metal from the hammer, skip this step. You need to remove approximately 1/32" (.031"). Filing the hammer nose is not practical due to radius and the requirement to maintain the exact contour. Carefully grind and polish the hammer nose. I do not recommend removing more than 1/32" (.031").  This will assure that the hammer is sufficiently depressed to be held at full cock. Scribe lines on both sides of the hammer nose following the same contour and remove metal to this line. A better method of assuring that you don't remove too much is to use a vernier caliper and measure from the flat on the bottom of the hammer to the nose.  Go slowly, measure often and then polish the nose. Be advised that altering the hammer may void the manufacturer's warranty.CARRIER ASSEMBLY
See:Intalling an Improved Carrier for an update ito install an improved carrier for the standare Marlin 1894's (Not the competition model)Leave the sides alone. Polish all burnished areas where the lever acts on the carrier.  Look for brass colored areas where brass rubbed off and polish those areas as well. Check the screw hole for burrs and remove.  Polish the screw where the carrier pivots. EJECTOR
Check for burrs and polish as required.  Polish the cam area where the bolt pushes the ejector down into its slot in the receiver. Spring tension on the ejector can be reduced by carefully bending the spring toward the ejector. Again, an after market one piece ejector/spring is available.MAGAZINE PLUG & SPRING
Remove the magazine tube plug and remove the 10 shot plastic plug from the spring. Replace the magazine tube plug and you can now load 13 rounds in the magazine.  I don't recommend that you remove any coils from the magazine spring unless it is hard to load rounds into the magazine.  If you do decide to remove any coils, proceed slowly and try often for proper feeding. Be safe, leave this spring alone.
Some people find the orange magazine follower objectionable.  Its good point is that it is easy to see through the loading gate to verify that the magazine does not contain any live rounds. Some feel that the plastic follower contributes to rust forming in the magazine tube.  While this may be true, a more likely reason has to do with the fact that few people remove the spring and follower and clean the inside of the tube much like they would a shotgun barrel.  For those individuals with a lathe, a replacement follower can be made out of aluminum bar stock. It too is easy to see through the loading gate.SAFETY
Everyone complains about the safety.  However, it does have a couple of good traits. One, it allows you to safely cycle rounds through the action to unload the magazine without the danger of an accidental discharge.  Two, you can dry fire occasionally without danger of breaking a firing pin.
Five things can be done to the safety.
1. Leave it alone and use it when desired.
2. Replace it with an after market dummy that fills the hole and appears as a bolt.
3. Remove the stock.  Turn in the safety set screw enough to lock the safety in the off position so that it can't be applied accidentally.
4. In a lathe, face off the left end of the safety so that it is flush with the left side of the receiver when in the off position. The safety can be applied by pushing on it with the end of a pencil.
5. Remove the safety, go to your friendly hardware store and purchase an "O" ring that fits the grove in the safety. After reinstalling the safety, slip the "O" ring over the left end. This will prevent the safety from being applied accidentally.
I have fired several thousand rounds through my Marlins and have never had my safety accidentally placed in the on position.REASSEMBLY
Reassemble the rifle in the reverse steps to disassembly.  Put a light coat of oil on all parts prior to reassembly. Do not tighten any screw all the way until everything is back together.  Then snug up all screws. Cycle the action several times to assure everything is working smoothly.  On my Marlin 1894, if the trigger guard plate support screw is too tight, the action will appear sluggish.  If this occurs on your rifle, back the screw off very slightly.
Every Marlin I have observed suffers from screws loosing up during heavy shooting. The most common is the carrier screw, but the hammer screw and the trigger guard plate support screw also may loosen. Keep a screwdriver close by when shooting and retighten the screws as required.  A better solution is to apply a SMALL drop of blue Loctite to the threads of these screws.  Loctite can be easily applied to the threads on the left side of the receiver using a toothpick. DO NOT USE RED Loctite or you may never take it apart again.
You have now tuned up your Marlin and are ready to enjoy a great rifle.