[Rob Moore]

How do I disassemble a marlin/glenfield model 20 bolt to replace the firing pin?

 

[Patrick Lyman]

Here you go.

 

[Patrick Lyman]

I believe they are the same as a Glenfield 25 and Marlin 780/781.

 

[Patrick Lyman]

I don't have any experience with that particular bolt. However, it should be a lot like most bolts. Remove the bolt (usually done by clearing the weapon pointing it in a safe direction and pulling the trigger while pulling the bolt out of the back) and once you have the bolt out it's usually just a couple of screws and pins holding it together.

Use the diagram above for the order. You're going to need gunsmith screwdriver set, a punch set and a block to punch the pins out on.

Do it the right way and use the right tools so you don't booger anything up.

May I ask why you're replacing the firing pin? If you don't know how to get it out, how do you know the firing pin is bad?

Hope this helps.

Patrick

 

[Patrick Lyman]

One more thing. I have seen on some smaller caliber, magazine fed, bolt action guns that you have to remove the whole action from the chassis sometimes to get the bolt out. I don't know if that's the case here, but you should know right away if you can't take the bolt out of the back of the gun while depressing the trigger or a bolt release somewhere on the gun.

Good luck!

Patrick

 

[Rob Moore]

I have removed the bolt with no problem. I ordered a new firing pin because I am getting some light strikes on the ammo. about 1 in 5 shells will not fire and show light firing pin strikes. The ammo is not the problem since it shoots in my other guns. According to the diagram, it looks like pin number 5 has to be removed. I have the right pin punches and armorers block but the pin will not budge. The schematic shows the pin being inserted from the right side so I have tried removing it from the left side. since that didn't work, I tried removing it from the right side also. same results. Some bolts just pull apart and are not pinned. Maybe I just need more force with the hammer on the punch but I don't want to damage anything.
I very much appreciate your reply to my request Patrick. Any additional help will be greatly appreciated. Thanks again.

Rob

 

[Rob Moore]

Hey Patrick,
I used a bigger hammer and got the pin out of the bolt. I removed the firing pin and related pieces and cleaned everything. While putting all of it back together, I discovered the new firing pin is 40 thousands too short. It will not protrude from the bolt face. Since I had cleaned up the grease and crud that was around the firing pin and channel, I put the old firing pin back in the bolt and reassembled it. It looks like the firing pin protrudes just right. I'll take it to the range tonight and give it a try. Thanks again for your input.

Rob

 

[Patrick Lyman]

Most pins in most gun brands from old to modern have slightly tapered pins and drive out of the gun from the left to the right (looking down the gun from butt to muzzle as if you were firing it)...and therefore drive back in from right to left...be careful. Its a good habit to follow this method, even if the pins aren't tapered.

Also, if it is an older weapon, with hard to find parts, you can add to the metal by adding a little weld or pein hammering the part to stretch the metal...and then filing it back down to tolerance. Does that make sense?

I hope you are getting that bolt apart.

Regards,
Patrick

 

[Patrick Lyman]

Sometimes a good cleaning to remove all of that heavy caked on spent powder and oil/grease that have collected more dirt does the trick. You can try polishing the pin and slot it rides in too...get rid of friction that might make the difference...especially if you haven't cleaned it in a while. Lightly oil it after...LIGHTLY! That oil turns to a gritty paste that will slow down a firing pin. That might make the difference on a smaller caliber weapon with smaller parts.

I like to use a synthetic oil. Synthetics tend to slowly evaporate over time. Natural oils breakdown and mixed with dirt and grease and powder to form a paste that becomes abrasive and full of friction.

Regards,
Patrick

 

[Patrick Lyman]

Oh, by the way I have a model 94 Winchester in 30 w.c.f. that is pretty old and the firing pin and channel it rides in (in the bolt) were so bad and caked with gunk that the pin was getting stuck and preventing primer strikes. The grit was so bad it was binding... I had hard time trying to just get the firing pin out of the back of the bolt for cleaning.



After a good thorough cleaning it slid nicely back into place and its ready to go for another 70 years!

P.S. - I made that rack... laser engraved the labels, hand cut the cradles, felt lined them and oiled the natural cut plank of walnut.

Regards,
Patrick

 

[Rob Moore]

Beautiful work and beautiful guns! After test firing the rifle last night, it still has the same problem. It looks like the firing pin protruds far enough. I may need a heavier main spring. One is on order.

 

[Patrick Lyman]

Thanks Rob! That spring should help do the trick.

Let me know if that fixes it.

Regards,
Patrick

 

[Rob Moore]

will do. thanks