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Old December 10, 2013, 02:49 AM   #1
vorgath
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Mosin slam fire question

When I used grease the bolt wouldn't slam fire when closing the bolt, when using gun oil everything seems more slippery but also sloppy.

My main question though is, is it the top of the trigger, or the sear, that stops the bolt from performing slam fire when one closes the bolt ?

I did do the Finnish bend the sear trick but I later on bent it back to straight.

Also the top of the trigger, I believe this is what is called the ... Bolt stop (??) .. Is rather worn out.

Plus the damn trigger is very sloppy, side to side movement.


I guess I'm asking to be a bit more educated by you guys regarding this, I do intend to either press in very very thin washers on the bottom of the receiver where the trigger and trigger pin goes, or press the metal together in a wise to make a slightly tighter fit.

Will I end up buying a new trigger and sear ? Quite possibly, however I'm not ready to give up yet lol
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Old December 10, 2013, 07:30 AM   #2
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Your "bolt stop" could be the problem. I believe that's the sear? You can find replacements somewhere I'd bet.
As far as shimming the trigger goes, I did it on my mosin and it helped a little, not a lot.
I would suggest you get the slamfire issue figured out before you go making things more sensitive for safety sake.
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Old December 10, 2013, 01:22 PM   #3
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Oh I'm not even concerned about trigger pull right now, my priority is keeping it safe
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Old December 10, 2013, 01:41 PM   #4
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You can try Numrich Gun Parts Corporation for Mosin parts.

www.gunpartscorp.com
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Old December 10, 2013, 05:24 PM   #5
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I had a Mosin sear break, the thing is just a spring with a sear block at the end of it.

I consider this highly dangerous. Not only to those down range but to yourself. This thing could go off prior to lug engagement or during partial lug engagement, or, it could go off unexpectedly, "going off half cocked"

It is my opinion you should buy several sears and a couple of cocking pieces. Somehow, some way, you are having a sear over ride. Given that the cocking piece surfaces are half this combination, by switching parts out you will figure if the problem is the sear or the cocking piece.

Direct pull triggers are tricky if the trigger sear/cocking piece surfaces are not exactly aligned. They are not exactly parallel or they would not reset, but stone them or bend them in the opposite direction, and they will not hold. Again, my opinion, if the mechanism held with grease, but not with oil, the difference in friction shows that the surfaces are out of alignment or insufficient for a good hold.
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Old December 10, 2013, 06:43 PM   #6
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My mistake, I could a swore the OP said something about trigger pull. Maybe I just assumed you said that because its in most other posts involving mosin triggers lol
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Old December 10, 2013, 10:13 PM   #7
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I'm going to try to sand and polish the rear part of the sear a tiny bit to see if it helps, in order to raise it, but yes definitely need some spare parts. Didn't even think about the cocking piece. Thanks
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Old December 10, 2013, 10:57 PM   #8
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Update

Ok I think I fixed it, I was thinking about the first time I reassembled the bolt I had issues with either too much stickiness, and sometimes slam fire.

So I took it apart, and rotated the firing pin 180 degrees ie half a turn. Preliminary testing looks good, but I'll see more once I put the rifle back together and do the drop slam the butt test.

So most likely it wasn't a grease or oil issue, but me not paying attention to details lol
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Old December 10, 2013, 11:18 PM   #9
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And the dumb ass of the week award goes to

This Guy !!
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Old December 11, 2013, 07:30 AM   #10
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Haha congrats! i have been the reciepient of this award many times myself!
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Old December 11, 2013, 09:53 AM   #11
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LOL

Anyway, thanks guys for your advice and patience
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Old December 11, 2013, 02:39 PM   #12
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Not fully screwing the firing pin is why Mauser invented his interrupted thread M96 firing pin.

You are lucky. If the firing pin had been out far enough, the rifle would have gone off out of battery.
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Old December 11, 2013, 04:29 PM   #13
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O.k....

I have owned several Mosin's over the years. Everything from M44's to a Finnish hex reciever. I have never had one slam fire. I am struggling to understand how firing pin protrusion could affect sear engagement. Pierced primer, light strike, perhaps. But it seems to me, as has been mentioned, that it is either cocking piece and/or sear engagement.

Just MHO
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Old December 11, 2013, 04:56 PM   #14
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Only way I can try to explain it would be .... slightly increased tension on the cocking piece ?

Because I agree, that it doesn't make sense, but after rotating it I cycled the action five times, with no slam fire issues what so ever.

I decided to try it because I looked at the sear, and it was still sticking up pretty damn far, so not too worn out.
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Old December 11, 2013, 05:35 PM   #15
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one place to buy parts to replace bad ones is buymilsurplus.com(if they have anything in stock)

first please take the bolt apart and clean everything, add oil + grease to apropriate places

once youve cleaned and then reassemble, take the mosin pin gaping tool out(small tool)

now tighten the bolt down, to the point were its tight but lines up with the notch on the back. try gaping the pin with the tool (youtube to review how to do this if needed)

recently i noticed on my mosin, i had to gape the pin a bit tighter , as the civilian rounds used by winchester and a few others has a very thin metal backing which when pierced can cause a blow back issue. this is due to mosin being meant for a military thick backed round , not an issue just shrink the pin down a little more than normal and this can solve the issue.

Now place into the gun and see how it cycles and moves. please note any areas of tight grip, or were it touches, add gun grease at those locations.

if nothing else try makeing a video to demonstarte the issue so we can have a bit more hands on approach and can tell you were the issue arises
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Old December 15, 2013, 03:36 AM   #16
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Hmmmm now I wish I had another Mosin next to me, all stock, not worked on. Reason is, I bought a cheapo fish weight scale to check what my trigger pull is now, and not sure it's correct, because it comes out at around 2 lbs.

I may have to try it on my lady's Beretta Nano, to see if it works properly to measure it.
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Old December 15, 2013, 12:59 PM   #17
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Quote:
O.k....

I have owned several Mosin's over the years. Everything from M44's to a Finnish hex reciever. I have never had one slam fire. I am struggling to understand how firing pin protrusion could affect sear engagement. Pierced primer, light strike, perhaps. But it seems to me, as has been mentioned, that it is either cocking piece and/or sear engagement.

Just MHO
You're correct.

Couldn't let this one go...
The firing pin, and how it's "set" within the cocking piece (protrusion) in no way can have any effect on the fire control mechanism. None.

How in the world could the sear lug on the cocking piece, or sear itself, be interrelated with the firing pin?

The MN fire control mechanism is about as simple as it gets.
Could be inadequate tension from the sear.
Could be a worn sear, or one with an incorrect angle that fails to properly engage the sear lug on the cocking piece.

The sear lugs on the cocking piece were often "reworked", meaning shortened, and reground, as they became worn. In the pic below, you can see that the lug on the cocking piece on the left is significantly shorter than the one on the right. This means the bolt on the left will "ride" slightly further forward in the receiver, but have no real effect on performance (other than a slightly shorter lock time I suppose).

This is most likely because it was worn/unsafe, and was shortened- with the correct engagement angle, to put it back into service. Could have been part of the re-arsenal process, who knows...

Anyway, the firing pin has absolutely nothing to do with premature/unintended release of the bolt.

Check the angles on the lug and the sear to be sure they are not worn, and check the sear to be sure you feel adequate tension on it when it's in place.

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Old December 17, 2013, 01:28 AM   #18
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Ok, I tried making a video but unfortunately after turning the pin I didn't get the camera angle right. It did slam fire, but eventually that disappeared.

I do believe the pressure, firing pin, whatever did ADD to the issue, but yes I have to redo the sear.

I did the drop test, slammed the rifle butt, and yes it slam fired.

So I have to work the trigger back to a safe condition, probably heavier than maybe the 2 lbs it may be at now.
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Old December 18, 2013, 11:46 AM   #19
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sad, im glad it did fix part of the issue, so your thoughts are to try and add to the trigger pressure?
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Old December 19, 2013, 09:13 AM   #20
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Yes, basically file a bit on the back part underneath, on the sear, so it brings the sear a bit higher up towards the cocking piece. Square it off, and then square off the cocking piece too.

Then work it from there, I may not have to do too much at all.

Thing is lol I liked having very nice light trigger pull lol I was actually surprised that it came out as around 2 lbs lol until I tried her Nano, which is 8 lbs lol
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Old December 19, 2013, 01:47 PM   #21
Duzell
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have you thought of using the washer trick?

adding a washer to the trigger system to lighten pull (i believe its installed on the screw)
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Old December 19, 2013, 03:49 PM   #22
vorgath
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Yes I did think about it, but right now I'm basically doing a reverse washer thing, bringing the sear a tiny bit higher up into the receiver.

I'm still aiming for a SAFE good operating rifle, with a trigger pull of 2 lbs or so.

It'll be interesting to see how she finally shoots, I may try with and without the limb-saver, and with and without the muzzle brake.
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