Bolt Wear / Contact

TexasGunner

TexasGunner

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I noticed after about 400 rounds through my M305 that the rear of my bolt is developing a some shiny spots on the back of the bolt just to the side of where the hammer strikes. Anything to be concerned about?

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Not good.
Can you please post pic's of the bridge on the under side of the reciever were that firing pin goes in and out of. Also the top of the hammer were you see the smooth part were the bolt comes in contact with it when resetting the trigger?
Another thing is the serries of numbers under the reciever flats on the bolt realse side.
Thanx.
Different this is number #2 I have seen of the supposed "new batch" with bolt issues for the record.
;)
 
im no expert by any means, but what grain bullets are you using? anything over 168 apparently beats the hell out of your bolt and receiver. when i first got my 12' this year, i had some peening on part of my bolt where the it contacts the accelerator rail but it seems to have just been that little bit, and its not a big deal. that looks like a perty serious damage
 
Mandown! said:
im no expert by any means, but what grain bullets are you using? anything over 168 apparently beats the hell out of your bolt and receiver. when i first got my 12' this year, i had some peening on part of my bolt where the it contacts the accelerator rail but it seems to have just been that little bit, and its not a big deal. that looks like a perty serious damage
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I'm Using 147 grain German made NATO headstamped ammunition.
 
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Here are the pictures of the trigger group and the receiver bridge. Note that the receiver has been re-finished since I put the rounds through it. Therefore, any wear on the receiver bridge would probably be soemwhat difficult to see. That said, the bridge doesn't look like it has any nicks or scuffs. I don't think there are any "fit" issues.

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If you look at the front of the hammer there is a protrusion (it's called the bolt camming lug), and focus on the front edge (as seen in your picture) you can see the edge is a bit buggered. This part of the hammer, is what fits into that recess in your bolt. As the bolt rotates out of battery, it is pushing against this bolt camming lug on the front of the hammer, while in the process of cocking the hammer. As for why it's getting all buggered up??? Maybe the parts are too soft?
 
Texas,... I just disassembled my 2009. I see wear at the exact same spots. I have around 800 rounds through mind, all NATO bullet weight 144-150 full power. The wear on my trigger group is just the finish worn off, while the wear on the camming lug is similar but approximately 1/4 the total surface area. If you view your nice close up of the tail end of the bolt, the debit in yours is two times wider than in mine. Mine is only as wide as the machined taper. It is half the height of yours, so again 1/4 the total wear area. I did exchange my op rod spring for a slightly heavier one from Hungry at around 400 rounds. Don't know if this helped, as I didn't notice any wear there till you just posted the pic's. The rifle still functions reliably with the spring but I don't know if it would slow down the wear you are showing. It would be nice if someone with a USGI trigger group and bolt in their Nork M-14, and an accurate round count,.. would post to show the difference if any.

Cheers.
 
Here are a few pictures of my Norc bolt and trigger group. Exact round count, I'm not sure of but its approaching 1200 I think.
My bolt shows virtually no wear in comparison to yours. I see a bit of wear on the bolt camming lug, but its in a different location than the wear on yours.

I don't know if I'm way off in my thinking here. Is it possible that the trigger group is sitting too far up into the stock causing the camming lug to interface with the bolt in the incorrect locations?

Crappy cell phone picture

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Also do you grease your M14? I think it kinda looks like grease in the picture of the bolt? Or do you use gun oil?
I can't see using oil instead of grease causing that much wear though.
 
So in the picture that I posted of my trigger group (which is manufactured by 7.62mm Firearms, not Norc) is the potruding part at the top right of the picture the part that makes contact with the "divot" in the back of the bolt where I'm getting the wear? Is that part at the top right of the picture the bolt camming lug?
 
Possibly. I may be wrong on this but the way the metal is peening over seems like its caused by impact more so than just abrasion? I think something doesn't line up properly in there.
 
TexasGunner said:
So in the picture that I posted of my trigger group (which is manufactured by 7.62mm Firearms, not Norc) is the potruding part at the top right of the picture the part that makes contact with the "divot" in the back of the bolt where I'm getting the wear? Is that part at the top right of the picture the bolt camming lug?
Click to expand...

Nope, you find that the USGI stuff will have slightly different dimensions than the Norinco. I noticed that when I replaced my Norc bolt with a USGI bolt. I not only had to lap the lugs, but also the hammer (norc trigger group) so that the bolt would travel freely (yes, I replaced the springs as well at the same time). I noticed the dimensions were close, but not quite the same on the norc bolt vs the USGI bolt. This likely could be the same issue you have here with the Norc bolt and USGI trigger group.

My new bolt does hot show appreciable wear or peaning, in fact it looks similar to the wear on CanuckR's bolt in his pics.
 
"So in the picture that I posted of my trigger group (which is manufactured by 7.62mm Firearms, not Norc) is the potruding part at the top right of the picture the part that makes contact with the "divot" in the back of the bolt where I'm getting the wear? Is that part at the top right of the picture the bolt camming lug? "

The camming lug is part of the hammer. It is the part of the hammer (if looking down from the top of the trigger group with hammer cocked) that protrudes forward of the hammer face on its left side. To see how it interacts with the bolt...start with your rifle completely assembled with bolt forward in battery and the hammer against the firing pin. Look through the open area in the receiver, behind the back edge of the bolt, on the right side of the rifle. You should see the hammer. Get yourself a strong light and shine it in that open area. By gently moving the op rod backward you should see the bolt start to rotate and the hammer move rearward. You should also be able to see the bolt camming lug and how it reacts with the groove in the bolt. Hopefully from there you will be able to determine why these two parts are causing so much wear to each other.
 
sobo4303 said:
I noticed that when I replaced my Norc bolt with a USGI This likely could be the same issue you have here with the Norc bolt and USGI trigger group.
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Make's complete sense, the M-14 is imperial/standard dimension's, the chinese copy is metric.
There will be small differance's in machining dimensions.
 
jakester said:
"So in the picture that I posted of my trigger group (which is manufactured by 7.62mm Firearms, not Norc) is the potruding part at the top right of the picture the part that makes contact with the "divot" in the back of the bolt where I'm getting the wear? Is that part at the top right of the picture the bolt camming lug? "

The camming lug is part of the hammer. It is the part of the hammer (if looking down from the top of the trigger group with hammer cocked) that protrudes forward of the hammer face on its left side. To see how it interacts with the bolt...start with your rifle completely assembled with bolt forward in battery and the hammer against the firing pin. Look through the open area in the receiver, behind the back edge of the bolt, on the right side of the rifle. You should see the hammer. Get yourself a strong light and shine it in that open area. By gently moving the op rod backward you should see the bolt start to rotate and the hammer move rearward. You should also be able to see the bolt camming lug and how it reacts with the groove in the bolt. Hopefully from there you will be able to determine why these two parts are causing so much wear to each other.
Click to expand...

Thanks for all the replies gentlemen, and this explanation. I will try to examine how these parts are interacting and report back.
 
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Oh-oh

I only have 20-30 rounds through mine and is starting to show wear.

What I did notice is that there were about 6 pok marks from hardness testing. Half of the are deeper then the rest. Unusual from my experience. I am starting to believe it is a hardening issue. Mine is a 2012, time to get Canadaammo involved.

Everybody check for the hardness test marks on your hammers.
 
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