With the recent buy of the 91/30 Mosin Nagants and the conversation during the group buy of the 7.62x54R ammunition I wanted to pass on an article written by a Mosin Collector regarding the sticking bolt problem some folks experience.
I hope you find it helpful.
"One of most frequent postings on all of the Mosin Nagant related forums is that of the problem of sticking bolts. Many people believe that this is related to the type of ammo they are using, others believe it is a headspace problems and still others attribute it to a rough chamber. They are all correct in their own way but often the problem is as simple as a dirty chamber!
When these rifles were placed in storage, they packed with a layer of waxy grease like preservative to protect the metal parts. Over the years some of this preservative hardened and formed a varnish like shell on the metal that is nearly transparent and very tough to break up with normal cleaning solvents. After cleaning a rifle using standard cleaning techniques, it is easy to believe that you got all of the preservative out of the chamber and off your metal parts. However, that film is still there. It's tightly bonded to the metal as a result of pitting or burrs in the chamber and it is trapped in the recesses of the locking ring where standard cleaning techniques can't reach it.
When you take your rifle out to the range and fire your first few shots, suddenly you can't open the bolt without really pounding on it. Why does this happen? When a round is fired, it generates a tremendous amount of heat and pressure in the chamber area. The charge causes the shell casing to become hot and to expand. At the same time the chamber walls become hot. The varnish like dried preservative heats up and becomes sticky. As the shell casing contacts the chamber wall and the sticky goo attached to it, there is a bonding that takes place as the metal of both surfaces cools in the first few seconds after firing. In turn, the bolt lugs are also trapped in this goo and the bolt becomes hard to open.
A rough chamber will make the problem worse by giving the goo more places to be trapped in and to adhere itself.
An out of spec chamber that is beginning to have headspace problems will also contribute to the problem by giving the shell casing more room to expand and more surface to come in contact with.
So...what do you do?
First of all, have your headspace checked to ensure you are within safe operating limits. You might consider swapping out the bolt head to see what effect this has on the headspace measurement. One you are satisfied that your headspace is safe, it is time to turn your attention to the chamber.
Use a chamber brush to clean your chamber. A chamber brush is designed to reach all of the areas within a chamber that a bore brush can not reach.
Use a good solvent like Gunscrubber or BreakFree and the chamber brush to vigorously clean the chamber. Follow that up with some Sweet's 7.62 on your chamber brush.
Take the chamber brush and Sweet's 7.62 to the range with you and fire as many rounds as possible before your bolt starts to lock up. Immediately clean your chamber while it is still hot and fire some rounds and clean again while it is still hot. Do this several times and you will notice that your bolt does not want to stick anymore.
If after this you are still experiencing sticking problems, take your rifle to a gunsmith and have the gunsmith polish the chamber and the problem should go away completely."
The Mosin page
I hope you find it helpful.
"One of most frequent postings on all of the Mosin Nagant related forums is that of the problem of sticking bolts. Many people believe that this is related to the type of ammo they are using, others believe it is a headspace problems and still others attribute it to a rough chamber. They are all correct in their own way but often the problem is as simple as a dirty chamber!
When these rifles were placed in storage, they packed with a layer of waxy grease like preservative to protect the metal parts. Over the years some of this preservative hardened and formed a varnish like shell on the metal that is nearly transparent and very tough to break up with normal cleaning solvents. After cleaning a rifle using standard cleaning techniques, it is easy to believe that you got all of the preservative out of the chamber and off your metal parts. However, that film is still there. It's tightly bonded to the metal as a result of pitting or burrs in the chamber and it is trapped in the recesses of the locking ring where standard cleaning techniques can't reach it.
When you take your rifle out to the range and fire your first few shots, suddenly you can't open the bolt without really pounding on it. Why does this happen? When a round is fired, it generates a tremendous amount of heat and pressure in the chamber area. The charge causes the shell casing to become hot and to expand. At the same time the chamber walls become hot. The varnish like dried preservative heats up and becomes sticky. As the shell casing contacts the chamber wall and the sticky goo attached to it, there is a bonding that takes place as the metal of both surfaces cools in the first few seconds after firing. In turn, the bolt lugs are also trapped in this goo and the bolt becomes hard to open.
A rough chamber will make the problem worse by giving the goo more places to be trapped in and to adhere itself.
An out of spec chamber that is beginning to have headspace problems will also contribute to the problem by giving the shell casing more room to expand and more surface to come in contact with.
So...what do you do?
First of all, have your headspace checked to ensure you are within safe operating limits. You might consider swapping out the bolt head to see what effect this has on the headspace measurement. One you are satisfied that your headspace is safe, it is time to turn your attention to the chamber.
Use a chamber brush to clean your chamber. A chamber brush is designed to reach all of the areas within a chamber that a bore brush can not reach.
Use a good solvent like Gunscrubber or BreakFree and the chamber brush to vigorously clean the chamber. Follow that up with some Sweet's 7.62 on your chamber brush.
Take the chamber brush and Sweet's 7.62 to the range with you and fire as many rounds as possible before your bolt starts to lock up. Immediately clean your chamber while it is still hot and fire some rounds and clean again while it is still hot. Do this several times and you will notice that your bolt does not want to stick anymore.
If after this you are still experiencing sticking problems, take your rifle to a gunsmith and have the gunsmith polish the chamber and the problem should go away completely."
The Mosin page