Mosin Nagant sticking bolt

[50 BMG]

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

 

[Jamie]

Thank you, good information right there!!!!

 

[Dench]

Non-Chlorinated Brake Cleaner also works excellent to get rid of this problem. its about half the cost of gun scrubber.

also, some ammo, like Czech made 7.62x54R will cause more bolt stick problems then other ammo.

 

[Wonder Bread]

Heavy ball ammo will also cause sticky bolt. It is loaded hotter and was intended for use in machinegun, and thus the case expands a bit more in the chamber. Some guns have issues with it, some do not.

Also, if you have a sticky bolt, check your fired brass for marks (scratches, small gouges, small indents, etc.). If you have some marks that appear in the same place on multiple pieces of brass, chances are that you have a chamber burr.

 

[depicts]

Thanks for the tips Fred. When did you get a Mosin? LOLOL

 

[Joe R.]

He has a nice M91 I'd kill him for!

Joe R. ( just got a nice M91 Finn from ZHA recently.)

 

[SKS Ray]

I've posted the shotgun cleaning brush info before but here is a detailed description from one from surplusrifle.com's articles:

Many new owners of Mosin-Nagant rifles and carbines have encountered what is commonly referred to as “sticky bolt syndrome”, where the bolt tends to be difficult to open after firing. This most often happens with the use of lacquered steel cased ammunition but can also happen with cases made from other materials.

Assuming headspace is correct (A “sticky bolt” on a rifle that has been cleaned, has no burrs but hasn’t been head spaced is an indication of overpressure. Don’t fire this rifle again until it has been checked by a competent gunsmith), there two probable reasons for this:

1) Cosmoline and old crud left in the chamber

2) A burr in the chamber

Lacquered steel cases (such as 60s Czech silver tip ammo) are particularly problematic when there is leftover cosmoline in the chamber. What happens is that when fired, the lacquer and the cosmoline heat up & flow together, forming a rough glue that makes it difficult to open the bolt. The biggest problem with cosmoline in the chamber is that it’s not usually easily detected. When dry cosmoline forms a shellac-like coating on the metal that can be difficult to detect.

Luckily both of these problems are easily fixed. We’ll start off with the most common which is crud in the chamber.

The fix for this is simple. Here I have outlined the “at home” method, with a note about the range method afterwards.

Tools & equipment needed:
End section of a cleaning rod
410 or 20 gauge brass brush
(2) .410 or 20 gauge cotton swab
Solvent: Hoppes No.9, Sweets, Ed’s Red, Acetone, any good solvent that will eat away the cosmoline
A drill
Steps taken:

1) Remove the bolt from your rifle.

2) Attach the brush to the end of the cleaning rod.

3) Chuck the cleaning rod into the drill.

4) Dip the brush into the solvent.

*WARNING* Do NOT let the brush come into contact with the rifling. We just want to clean the chamber, not wear down the barrel. While it may not do much damage if the brush touches, why do any damage at all?

5) Put the cleaning rod through the receiver so that the brush is inside the chamber but not touching the rifling.

6) Using low to medium speed run the brush clockwise around the chamber for 10 to 20 seconds.

7) Remove the drill, rod & brush from the rifle.

8) Using a lint free rag and your finger remove as much cosmoline as you can.

9) Replace the brass brush on the cleaning rod with the cotton swab.

10) Dip the cotton swab in the solvent, and repeat steps 5-8.

11) At this point most of the cosmoline should be gone. Replace the solvent & cosmoline soaked swab with a clean one.

12) Run the dry swab the same as above, but for only 5 seconds.

13) Done!

This may not remove all the cosmoline in one go, but the bolt should be easier to open afterwards. If the bolt is easier to open but still “sticky”, simply repeat the procedure until all the cosmoline is gone.

The preferred (and most fun!) method of cleaning is the same as above, but it takes place at the range. Hot cosmoline flows & is much easier to remove than when hardened.

The steps for range cleaning are:

1) Fire 5 shots or so until the chamber is good and hot then open the bolt. The bolt will likely be quite difficult to open by this time, a rubber mallet can come in handy for this purpose.

2) Use your finger to run a lint-free rag dipped in solvent around in the chamber, removing as much cosmoline as you can.

3) Use the dry end of the rag to remove the leftover solvent and some additional cosmoline.

4) Repeat steps 1-3 until the bolt is easy to open.

5) Done! Now, wasn’t that a fun way to clean?

If the bolt still has the same difficulty opening as it did before cleaning the chamber may be an indication that there’s a burr in the chamber. Again, this is assuming that headspace has been checked and is correct. If there are scratches on your casings this is a sure sign of burrs.

Fixing burrs is also very easy:

Tools and Equipment needed:

a fine, curved file
Steps:

1) Find the burr. This is easily done by running your finger around the chamber.

2) Using the curved file, lightly file away the burr until you can’t tell the difference between where it was and the rest of the chamber by feel.

While a Dremel tool could be used for deburring, I strongly recommend that it not be used. It’s far too easy to grind off too much metal using a power tool. As with everything else, it’s much easier to take away material than it is to add it back on. Some patience and a steady hand will get those burrs out

Clean and deburr your chamber and keep those bullets flying!


Adobe PDF Downloadable Version of Article


Article Written by: Zeliard

 

[Kerriganm49]

I concur with Milsurps 4 me, on the shotgun brush and mop in the chamber. But also recommend, The bolt is the next part to clean well, take it apart, it won't brake, and they are easy to put back together, and re-adjust as everyone has told you using the feild combo tool that came with most Mosin Nagant surplus rifles. By the way, I'm new to this Forum, but belong to many other, and most all that everyone has told you is great. I use to live in MA before taking a job with the USAF after NAS South Weymouth closed years ago. Still have family up that way and all. I miss the fall and spring time the most. Only Hot summers and not much fall or spring and cold winters.
Good luck and good shooting!

 

[BigBill]

My very first finnish mosin purchase was a VKT M39 and it had a sticky bolt problem. I cleaned the chamber squeeky clean and took an oily patch and lubed the chamber. Then i took a dry patch and wiped it out leaving a light film of oil in the chamber as a release agent. The very next trip to the range the bolt worked awesome. I figured the sticky bolt was from either crud/dirt in the chamber or a dry chamber which with some of the coatings on the cases can cause them to stick.