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Posted: 2/14/2013 5:13:22 PM EDT
First off, I know it's a Mosin I am dealing with here.
Ok, so I have a run-of-the-mill 91/30 Mosin from AIM. Everything seems to be in pretty dang good shape on it for what it is. I have been having Hell with it at the range. You can chamber and eject ammo perfectly fine when not shooting, but once you chamber and fire a round the bolt becomes almost impossible to maneuver. It takes my entire body weight being it to free the bolt and chamber another round. This happened the first 20 rounds but then it started to loosen up a tad. Can anyone tell me what may be my issue here? Ammo is the good surplus Yugo ammo from the 60's. |
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Quoted: Quoted: Did you clean the chamber really well, or check the chamber for possible burrs? Gun was cleaned throughly and no burrs whatsoever in the chamber. It's making my head hurt trying to figure out what is making it do this... Really clean the decades of cosmoline? Grease the wear points and you might want to think about having the headspace checked if it is as difficult to manipulate the bolt as you say. |
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Quoted:
Quoted:
Quoted:
Did you clean the chamber really well, or check the chamber for possible burrs? Gun was cleaned throughly and no burrs whatsoever in the chamber. It's making my head hurt trying to figure out what is making it do this... Really clean the decades of cosmoline? Grease the wear points and you might want to think about having the headspace checked if it is as difficult to manipulate the bolt as you say. Looking at it closely now. The cocking knob is visibly rubbing against the receiver on the left side when in the fired position. That would explain the reason I do not have any problems chambering rounds when the knob is in the cocked position.... I'm thinkingthe problem lies somewhere in the cocking knob and bolt body. |
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So try this:
Chamber a live round and try to eject it . FULL SAFETY PRECAUTIONS! Is that stiff at all? Should be no resistance to doing this. Shoot it and try to rechamber a spent case. First inspect it for any deformities. Any resistance on a cold chamber to ejecting it? |
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Quoted:
So try this: Chamber a live round and try to eject it . FULL SAFETY PRECAUTIONS! Is that stiff at all? Should be no resistance to doing this. Shoot it and try to rechamber a spent case. First inspect it for any deformities. Any resistance on a cold chamber to ejecting it? Never any problems when knob is cocked and not fired. When ejecting spent rounds, the bolt is sticking bad. No marks or wear whatsoever on casings. |
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Quoted:
Yeah, but try a cold spent one. It will have expanded a bit. This will tell if its a tight chamber. ETA: are these copper washed cases or lacquered? Got it! They are lacquered silver tipped from 1965. Its supposed to be good stuff but I am new with Mosins. 
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Ok, so here is a thought.
Get a .45 barrel swab. Soak it in mineral spirits, break cleaner, or thinner. CLEAN out the chamber. Leave the swab in there to dissolve anything. Try shooting it again. If the first few shots eject normally, you can conclude that then lacquer is building up and causing the problem. Might also be a tight chamber contributing to this. See if you can find some copper washed ammo. Clean the chamber well again and shoot it. If life is good, then you know it's the combination do the gun and ammo. |
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Quoted:
Ok, so here is a thought. Get a .45 barrel swab. Soak it in mineral spirits, break cleaner, or thinner. CLEAN out the chamber. Leave the swab in there to dissolve anything. Try shooting it again. If the first few shots eject normally, you can conclude that then lacquer is building up and causing the problem. Might also be a tight chamber contributing to this. See if you can find some copper washed ammo. Clean the chamber well again and shoot it. If life is good, then you know it's the combination do the gun and ammo. Will do. I took the bolt and gun completely apart and rinsed in spirits before the first shoot. I will try it again and see. |
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Have you done this:
http://www.surplusrifle.com/shooting2005/eliminatesbs/index.asp 20 gauge brush on a section of cleaning rod in a drill. Get a little solvent on it and run it in the chamber. Try to avoid bottoming out in the throat. |
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Quoted:
Have you done this: http://www.surplusrifle.com/shooting2005/eliminatesbs/index.asp 20 gauge brush on a section of cleaning rod in a drill. Get a little solvent on it and run it in the chamber. Try to avoid bottoming out in the throat. This, there are a couple of videos on Youtube that go over this as well. |
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Welp given the ammo you probably have Sticky Bolt, common issue. As the chamber heats up the lacquer gets soft and tends to stick to the inside of the chamber. It will give the bolt a spongy feeling after about 5-10 rounds and become very difficult to open. Common fix is mineral spirits and a .45 or 20 Gage bore swab spun in the chamber a lot. And by a lot, most places like to recommend a power screw driver.
However to help narrow it down here is some other things to try. If you dry fire with out a case dose it do the same thing? If so then it is not sticky bolt so first check for Cosmoline in the locking lug channels, preferably with a q-tip or something as you can't actually see in them very well. Then fully dissemble the bolt and check the camed surfaces between the cocking knob and the bolt body for cosmoline. If they are clean it is most likely a poor cocking knob/Bolt Handle match up there are some guides for "fine tuneing" bolts that help but most of the time it is just easier to change the cocking knob. If load a empty case is the bolt difficult to close? If so you may be under the minimum head space causing the rim to give you excessive pressure against the bolt face causing the bolt face to rotate hard, and thus the bolt. In which case you need to check the head space, and possible swap out the bolt faces. Also remember the Mosin bolts Cock on Open, so it is going to open hard compared to most any other rifle. Also the cocking knob is suppose to rub there. |
| Besides what has been mentioned above, are there any "swipe" marks on the case rim of a fired case? I have found on some Mosins, the relief "rim" around the bolt face has a burr or sharp edge on the ejector groove. They will catch on the edge of the case rim and shave some metal from the rim. Only seems to happen after round is fired, headspace was OK. I have used a jewlers file to bevel the edges of said groove with success. |
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Start with a 20 ga bore brush soaked in Hoppes or mineral spirits and chuck it up into a drill on a section of cleaning rod. Run it in the chamber as long as you deem necessary and follow with a mop. I've found this to resolve most of my sticky bolt issues. Dried cosmoline and crud can be almost impossible to detect in the chamber even with a good light. I would try this before exploring possible mechanical issues. Polishing the chamber can also be a solution, but great care should be taken with the throat.
Previous posts about mechanical issues are also excellent places to look. EDIT mentioned above...sorry |
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