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Mosin Nagant Bolt Disassembly/Reassembly Tutorial
The Mosin Nagant bolt is incredible in its simplicity of design. It can be disassembled and reassembled without any tools, though for best performance, a firing pin protrusion gauge can be used. The gauge doubled as a screwdriver and was issued in the standard cleaning kit.
The advantage to such a simple system is that relatively untrained users could effect repair in the field easily and clean the bolt rapidly. This is especially important during the cold winters in Russia where an oiled bolt could rapidly become a liability.
Step 1 - Gathering required tools.
This is pretty easy, you don't actually need any tools! Remove the bolt from the rifle by first checking that the rifle is unloaded. Retract the bolt until fully open and then depress the trigger. The bolt will slide out the back of the action.
The buttstock can be used as a sacrificial piece of wood during bolt disassembly. This is what the Russians used as evidenced by common indentation markings found on many stock sets, but I prefer to use a piece of scrap wood so as not to further damage the appearance of my Mosin rifles.
Lastly, get the firing pin protrusion gauge out of your cleaning kit. Better to measure than to use guesswork!
Step 2 - Removing the connector bar.
Grasp the knurled part of the cocking piece and pull it back approximately 1/8", then rotate it 1/4 turn counterclockwise and slowly release it. This simulates the position the bolt rests in when the rifle action is normally closed.
The connector bar and bolt head will then slide free of the bolt.
Grasp the bolt head and rotate it 1/2 turn clockwise until it stops rotating.
It will now slide free of the connector bar.
We're half way there!
Step 3 - Removing the cocking piece.
Now it's time to make use of our piece of scrap wood. As I said earlier, you COULD use your buttstock for this - this is what soldiers in the field often did - but I suggest you not abuse your stock like that unless your Mosin truly is a truck gun you don't care for.
Firmly grasp the bolt handle and place the tip of the firing pin onto the piece of wood as shown. Ensure you keep the pin vertical so as not to put transverse stress on the pin that could bend the tip. Using firm constant pressure push down hard on the bolt handle until the cocking piece rotates freely on the firing pin.
Now turn the cocking piece counterclockwise until it unthreads completely from the firing pin, all the while keeping downward pressure on the bolt body. Once the cocking piece threads off, SLOWLY take pressure off the bolt handle to relieve the pressure on the firing pin spring. You don't want the bolt body to fly up and strike your forehead!
Step 4 - Removing the firing pin.
Now that the cocking piece is off, the firing pin and spring just pull out from the front of the bolt.
Now it's all disassembled!
Step 5 - Reassembly.
To reassemble the bolt, simply follow the above instructions in reverse until you get to Step 2. Slide the connector bar and bolt head over the firing pin and onto the bolt body. Take care to ensure the two prongs at the rear of the connector bar slide over either side of the cocking piece's sear engagement surface. This is the little T-shaped nub on the cocking piece that works against the trigger sear to fire the rifle. You should be able to now see the firing pin protruding from the bolt face.
Now is the time to use your firing pin protrusion gauge. On it you will find a "no go" notch .75mm in depth, a "go" notch .95mm in depth, and a firing pin wrench so you can quickly turn the pin in or out to adjust the depth. It is important to note that the base of the connector bar is purposely slotted the same size so that it too can be used to adjust pin depth, but why risk bending you connector bar over time when the gauge tool is so convenient?
Here you see the tool being used. As you can see, a properly protruding pin should not be able to slide under the "no go" notch without hanging up.
Next, a properly protruding pin should be able to slide under the "go" notch without hanging up on the gauge.
And there you have it! Your bolt is back together and the pin protrusion is properly set. Time to go shooting!
The Mosin Nagant bolt is incredible in its simplicity of design. It can be disassembled and reassembled without any tools, though for best performance, a firing pin protrusion gauge can be used. The gauge doubled as a screwdriver and was issued in the standard cleaning kit.
The advantage to such a simple system is that relatively untrained users could effect repair in the field easily and clean the bolt rapidly. This is especially important during the cold winters in Russia where an oiled bolt could rapidly become a liability.
Step 1 - Gathering required tools.
This is pretty easy, you don't actually need any tools! Remove the bolt from the rifle by first checking that the rifle is unloaded. Retract the bolt until fully open and then depress the trigger. The bolt will slide out the back of the action.
The buttstock can be used as a sacrificial piece of wood during bolt disassembly. This is what the Russians used as evidenced by common indentation markings found on many stock sets, but I prefer to use a piece of scrap wood so as not to further damage the appearance of my Mosin rifles.
Lastly, get the firing pin protrusion gauge out of your cleaning kit. Better to measure than to use guesswork!
Step 2 - Removing the connector bar.
Grasp the knurled part of the cocking piece and pull it back approximately 1/8", then rotate it 1/4 turn counterclockwise and slowly release it. This simulates the position the bolt rests in when the rifle action is normally closed.
The connector bar and bolt head will then slide free of the bolt.
Grasp the bolt head and rotate it 1/2 turn clockwise until it stops rotating.
It will now slide free of the connector bar.
We're half way there!
Step 3 - Removing the cocking piece.
Now it's time to make use of our piece of scrap wood. As I said earlier, you COULD use your buttstock for this - this is what soldiers in the field often did - but I suggest you not abuse your stock like that unless your Mosin truly is a truck gun you don't care for.
Firmly grasp the bolt handle and place the tip of the firing pin onto the piece of wood as shown. Ensure you keep the pin vertical so as not to put transverse stress on the pin that could bend the tip. Using firm constant pressure push down hard on the bolt handle until the cocking piece rotates freely on the firing pin.
Now turn the cocking piece counterclockwise until it unthreads completely from the firing pin, all the while keeping downward pressure on the bolt body. Once the cocking piece threads off, SLOWLY take pressure off the bolt handle to relieve the pressure on the firing pin spring. You don't want the bolt body to fly up and strike your forehead!
Step 4 - Removing the firing pin.
Now that the cocking piece is off, the firing pin and spring just pull out from the front of the bolt.
Now it's all disassembled!
Step 5 - Reassembly.
To reassemble the bolt, simply follow the above instructions in reverse until you get to Step 2. Slide the connector bar and bolt head over the firing pin and onto the bolt body. Take care to ensure the two prongs at the rear of the connector bar slide over either side of the cocking piece's sear engagement surface. This is the little T-shaped nub on the cocking piece that works against the trigger sear to fire the rifle. You should be able to now see the firing pin protruding from the bolt face.
Now is the time to use your firing pin protrusion gauge. On it you will find a "no go" notch .75mm in depth, a "go" notch .95mm in depth, and a firing pin wrench so you can quickly turn the pin in or out to adjust the depth. It is important to note that the base of the connector bar is purposely slotted the same size so that it too can be used to adjust pin depth, but why risk bending you connector bar over time when the gauge tool is so convenient?
Here you see the tool being used. As you can see, a properly protruding pin should not be able to slide under the "no go" notch without hanging up.
Next, a properly protruding pin should be able to slide under the "go" notch without hanging up on the gauge.
And there you have it! Your bolt is back together and the pin protrusion is properly set. Time to go shooting!
Note: The opinions expressed herein or statements made in the article below are solely those of the author, and do not necessarily reflect the views of the Military Surplus Collectors Forums, or the ownership and moderation group of this site. MILSURPS.COM accepts no legal liability or responsibility for any claims made or opinions expressed herein. Also, please note that MILSURPS.COM recommends that any member of these forums, or a reader of this article, try this type of experimentation without the proper knowledge, equipment and training.
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