Norinco M4 bolt not going all the way forward

Well I tried taping the hammer down and it is the hammer. With the hammer a millimetre or two lower the gun would be fine. The added force of slamming the bolt home does not overcome the snag though. Beating on the forward assist does not overcome it either. I have ordered a new hammer and firing pin. Thank you to everyone for your suggestions.

Does anyone think that this rifle would damage a Colt BCG if I shot it like that?
 
cr5 said:
Telling him to contact the previous owner to get the truth out of him and to leave appropriate feedback for him if he continues to deny knowledge of the problem to warn the of us not to deal with someone selling their problems on the EE is far from turning this into an EE rant.
Almost all posts have been on topic with a couple minor exceptions.

Roddy, PM me if you have time off tomorrow and want a second set of eyes to try to figure it out.
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This is my thoughts on this as well. I wouldn't want to be doing business with somebody who is selling a non-functional firearm and then claiming ignorance.
 
Shep546 said:
This is my thoughts on this as well. I wouldn't want to be doing business with somebody who is selling a non-functional firearm and then claiming ignorance.
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Particularly when you know to a certainty that the seller was aware of the problem.
How did you know?
 
I probably broke the thing assembling it, enough about the seller. He has been very helpful. I have ordered a new hammer and springs and I think that should fix it.

Until the new parts arrive I just want to know if mismatched bolt carriers can mess up the carrier or rifle.
 
As long as everything is in spec, and the wear on neither part is excessive, your Colt BCG SHOULD work in your Norc BUT to be sure you should have the head space checked. Normally it's not an issue, but the possibility does exist.
 
tiriaq said:
Particularly when you know to a certainty that the seller was aware of the problem.
How did you know?
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What could possibly have happened to this firearm in transport that would cause this issue to happen?

Look at the C7 rifles in basic training facilities all across Canada that have had thousands and thousands of people who have never touched a firearm before throwing bolts in and out, stripping, etc. and they don't have issues with them.

Here we have a guy with AR15 experience who can't get it to assemble and operate properly...
 
And none of the thousands of C7/C8 rifles have a notched hammer, flanged firing pin, and bolt carrier cut designed to prevent auto fire.
 
tiriaq said:
And none of the thousands of C7/C8 rifles have a notched hammer, flanged firing pin, and bolt carrier cut designed to prevent auto fire.
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How could this be broken by inserting the bolt? how is it even possible to insert in incorrectly?
 
i used to have a similar issue with my nork. it would only happen though when using the norinco mags though. What mags are you trying to use?

It would happen on a mag change, you would put in the new mag, and it would be half cocked, jam when you tried to close the carrier. If you pulled back the charging handle though, it would catch where it was suppose to.
 
Roddy said:
I probably broke the thing assembling it, enough about the seller. He has been very helpful. I have ordered a new hammer and springs and I think that should fix it.

Until the new parts arrive I just want to know if mismatched bolt carriers can mess up the carrier or rifle.
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I don't see how that is possible. What is there to break putting an upper on a lower?
You already own another AR, have you never separated the upper and lower before? I can't think of any way to break something slipping a BCG into an upper then slipping it onto a lower and pushing 2 pins through as long as you didn't have to use a hammer to do it.

I'm pretty sure he knew about the issue.
 
jdman, no mags, no ammo. Just installing BCG and matching the upper and lower.

It has closed for me twice out of a few dozen tries so I think it is close to fitting. With the hammer taped down the bolt closed no problem. I have ordered a new notchless, rounded type hammer and a spare fring pin.

In the meantime I am going to file a small amount of material off of the notch in hammer it has now as see if that fixes it. I think it is catching right on the sharp edges of the notch. I may also put the firing pin in a cordless drill and round the collar/shoulder down a little to see if that helps.

In this picture ignore the hook on the back of the M16 bolt. I am concerned about the notch on the front of the hammer on the right. When the hammer is cocked I believe that catches the firing pin collar.
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I want to round my hammer so it looks more like the one on the left.

This was a used gun, used guns sometimes have problems. I don't think the seller was trying to deceive me. I am not too worried about it. Thank you to everyone who had helpful ideas and suggestions.
 
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Take the hammer assembly and spring out and see if the carrier closes. If not, try the bolt catch.

Most likely the hammer is catching on the FP - looks like a FP mark on the hammer notch.

The wrong notched hammer could cause this as well. Ordering a non-notched hammer may not solve your problem. Fixed one like that this summer - non notched hammer was too wide and jammed in the groove.

Check the FP dimensions above or compare it to your Colt FP. The flange should be smaller.

Could also be be missing/broken a disconnect spring, worn disconnect or worn upper inner notch. This would allow the hammer to rise prematurely and follow the carrier causing the notch to grab the FP.
 
Roddy said:
jdman, no mags, no ammo. Just installing BCG and matching the upper and lower.

It has closed for me twice out of a few dozen tries so I think it is close to fitting. With the hammer taped down the bolt closed no problem. I have ordered a new notchless, rounded type hammer and a spare fring pin.

In the meantime I am going to file a small amount of material off of the notch in hammer it has now as see if that fixes it. I think it is catching right on the sharp edges of the notch. I may also put the firing pin in a cordless drill and round the collar/shoulder down a little to see if that helps.

In this picture ignore the hook on the back of the M16 bolt. I am concerned about the notch on the front of the hammer on the right. When the hammer is cocked I believe that catches the firing pin collar.

I want to round my hammer so it looks more like the one on the left.

This was a used gun, used guns sometimes have problems. I don't think the seller was trying to deceive me. I am not too worried about it. Thank you to everyone who had helpful ideas and suggestions.
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Don't do either one of those things. The notch is designed to catch the FP for a reason. Thousands of these were produced and function just fine. If it is catching it, then something else is wrong with your trigger mech.

The hammer is case hardened to a depth of a few thousands of an inch. You will destroy it.

Likewise the FP will be destroyed by modifying it.

As above, if the problem is the disconnect or upper inner notch, you will have destroyed parts for no reason.

It is best to diagnose the real cause of the problem and fix it correctly rather then get a mechanism that burst fires or breaks while firing.
 
I think if you start filing and grinding on the hammer it will remove any surface hardening and create some further potentially unsafe problems.
 
I will not file down any parts then. I have also noticed that if I hold down the trigger the bolt will go all the way forward whether the safety is on or off. After I release the trigger I hear a soft click and the hammer is still cocked. Does that narrow it down?
 
Yes. That means the hammer is held down on the lower notch engaged on the trigger.

That means when you release it, the disconnect is failing to engage the hammer or releasing it prematurely.

Assemble rifle, #### the action, fire the action, keep the trigger held to the rear and #### it again. Now force the selector slowly onto safe (keeping trigger firmly held to the rear).

If it goes onto safe with a soft click that is normal. If it fires (big click), the trigger mech is doubling. That would cause your problem exactly as described.

Check disconnect, disconnect spring, fouling in the trigger channel, worn upper inner notch on hammer.

Worst case is hammer or trigger pin holes are enlarged due to using a hammer to assemble hammer and trigger pins with a hammer or such. Not much fix for that.
 
I did the test. The click to safe isn't really soft but I can still switch it back to semi and fire it. I can almost see the hammer pin wiggle when I dry fire if that's abnormal at all. I will keep looking into it and strip the trigger group at some point.

Edited to add:
I did the same test with the just the lower using my finger to #### the hammer. The hammer just barely hangs on the disconnector and usually slips off. So the problem seems to be the hammer not being held by the disconnector and dropping prematurely.

I am sorry if I have a lot of the terminology and descriptions wrong but I am new to AR-15s.
 
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Not to beat a dead horse, but it is highly unlikely that this rifle did not have this problem in the hands of the previous owner, as this is a pretty serious malfunction. Just curious, did you strip the trigger group out when you received it?
 
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