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Posted: 8/21/2011 9:26:30 AM EDT
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Well i shot my new Waffen Werks AK-74 today and it went smooth for a hundred rounds. No Keyholes and was pretty damn accurate. But after 100 rounds, this happened.
The bolt got stuck and would not close and it was pretty hard to pull back. Finally got it back and round came out. Even though the round was out, the bolt still would not close all the ways so it wasnt the ammo. Took it apart and this is what i found This is the piston head that had some kind of metal fouling other than copper or lead 
The chunk of the bottom is what was stuck onto the piston face. The chunk on the top came out when i blew into the gas block 
This is the gas block. Looks like it was impacting the back of the gas block. Is this chrome? 
I cleaned the rifle completely afterwords and its now smooth like butter but why did this happen? Is this something to worry about? The piston doesnt seem to touch any other part of the gas tube or block. It moves the way its supposed to. Other than that i had no other problems with this rifle, it was fantastic. Can anyone provide some insight? If it helps the ammo was 5.45 Silver Bear and the rifle is a Waffen Werks Bulgarian kit build on a US Barrel |
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Might be the gas port is shearing metal off the bullet jackets as they pass. Off the top of my head, I think the Silver Bear has mild steel bullet jackets.
Do the debris chunks stick to a magnet? Does the rifle have a US barrel? If it's a US barrel, maybe the gas port hole is ragged. |
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The chunks do not stick to a magnet. Atlantic Firearms webpage say it has a NEW Chrome lined barrel so im assuming its US made and not surplus.
The side of the piston also had a skid mark of this metal on the side of the head which makes it seem like it was shearing off metal from the walls of the gas block. If thats the case then that would explain where it impacts against the gas block and creates a chunk. Not sure how this is even happening because the piston seems to move freely like its supposed to |
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Did you give it a cleaning before taking it out? mine had some crud that was like old cosmo on the bolt head and in little crevices. I'm thinking that if it was the gas port shearing off pieces of bullets, that it would affect accuracy? This thing was shooting dead nuts accurate so if it was shaving off the bullet then i dont think it was losing accuracy. Since these chunks dont stick to a magnet that pretty much cancels out the chrome. I didnt notice anything out of the usual in the barrel and the gas port |
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First question: Did you disassemble and clean and inspect the rifle before taking it to the range?
If not, it's possible some sort of foreign matter was left in the gas system at the factory and finally shifted to where it could interfere with the gas piston. I doubt it's shaved hard chrome. First, hard chrome is applied in a layer only about 0.0002" thick, which is THIN. Second, it bonds into the metal so it would be almost impossible for it to be shaved. Even if it could be shaved off, it would be in a super thin shaving, not at all as large as what your pictures show. Hard chrome is so hard that it would have fragmented into tiny bits. All I can think of is some kind of foreign matter that came up out of the gas port or was already in there when you got it. A possibility is a burr of metal trapped inside the port or gas block during assembly that finally broke off and was blown into the gas block. Since it's not magnetic, that would argue for lead. Commercial Russian 5.45 ammo has a lead core which is exposed on the rear of the bullet. Possibly somehow some lead was extruded from the rear of a bullet and was blown up the gas port. I'd suggest using a "lead-away" cloth to wipe the gas piston and the inside of the gas block and see if the scraped areas wipe off. If they do wipe off, it isn't metal shaving off the piston or gas block, but some sort of external debris. Likely, this was some off the wall anomaly and will never happen again. My best guess: Something was in the rifle when you got it and it took a few shots before it caused the problem. |
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First question: Did you disassemble and clean and inspect the rifle before taking it to the range? If not, it's possible some sort of foreign matter was left in the gas system at the factory and finally shifted to where it could interfere with the gas piston. I doubt it's shaved hard chrome. First, hard chrome is applied in a layer only about 0.0002" thick, which is THIN. Second, it bonds into the metal so it would be almost impossible for it to be shaved. Even if it could be shaved off, it would be in a super thin shaving, not at all as large as what your pictures show. Hard chrome is so hard that it would have fragmented into tiny bits. All I can think of is some kind of foreign matter that came up out of the gas port or was already in there when you got it. A possibility is a burr of metal trapped inside the port or gas block during assembly that finally broke off and was blown into the gas block. Since it's not magnetic, that would argue for lead. Commercial Russian 5.45 ammo has a lead core which is exposed on the rear of the bullet. Possibly somehow some lead was extruded from the rear of a bullet and was blown up the gas port. I'd suggest using a "lead-away" cloth to wipe the gas piston and the inside of the gas block and see if the scraped areas wipe off. If they do wipe off, it isn't metal shaving off the piston or gas block, but some sort of external debris. Likely, this was some off the wall anomaly and will never happen again. My best guess: Something was in the rifle when you got it and it took a few shots before it caused the problem. Great response. To answer your first question, when i got the rifle, i took it apart, inspected it and noticed it looks like it hasnt even been fired, or atleast no more than 5 rounds. All i did was give it a quick wipe down not a full cleaning. As far as the bullet goes, i thought the whole point of a 90 Degree gas block was so it fixed the problem with bullet shearing? While i do believe there could have been fouling inside the rifle already, that was a pretty decent amount of fouling considering the rifle functions perfect dry. Not really sure where that fouling could have hid where the piston didnt get stuck to it unless the fouling was on the walls. Seemed like the chunks were too big to hide in the gas port hole |
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I buy Com block- to avoid these issues. What issues ? I've shot thousands upon thousands of rounds of WOLF 5.45. as others have, with no issues. A fluke can happen with any type of ammo. If someone has a bad surpuls round or it causes an issue you can't damn the brand as a whole.In a week someone will post about rust left from surplus and someone will repy this is why they shoot WOLF, to "avoid these issues" ; same thing. Probally a bad round and probally a isolated incident. It happens. |
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I buy Com block- to avoid these issues. What issues ? I've shot thousands upon thousands of rounds of WOLF 5.45. as others have, with no issues. A fluke can happen with any type of ammo. If someone has a bad surpuls round or it causes an issue you can't damn the brand as a whole.In a week someone will post about rust left from surplus and someone will repy this is why they shoot WOLF, to "avoid these issues" ; same thing. Probally a bad round and probally a isolated incident. It happens. Ive shot thousands and thousands of rounds of Wolf through my AK's and ive never had a single problem other than this. Its probably a fluke like you said. |
| I've never seen or heard of anything like this. A clue is that 100 rounds fired without incident, possibly indicating that there was no foreign material in the gas system at the beginning of firing. The only thing that comes to mind is that the material was shaved off bullets by a rough gas port in the barrel and after 100 rounds had built up enough to jam the gas piston within the gas block. Or, if the bullets have open bases, there could be some lead flakes on each one that could after extended firing cause lead to build up in the gas block. Either way, it must have come from the ammo. It is very obvious that the rifle is not eating itself and getting choked on the bones. :) I would try some ammo by a different maker and see what happens. |
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I've never seen or heard of anything like this. A clue is that 100 rounds fired without incident, possibly indicating that there was no foreign material in the gas system at the beginning of firing. The only thing that comes to mind is that the material was shaved off bullets by a rough gas port in the barrel and after 100 rounds had built up enough to jam the gas piston within the gas block. Or, if the bullets have open bases, there could be some lead flakes on each one that could after extended firing cause lead to build up in the gas block. Either way, it must have come from the ammo. It is very obvious that the rifle is not eating itself and getting choked on the bones. :) I would try some ammo by a different maker and see what happens. Next time i am going to try some of the surplus i have. Only reason why i used this Silver Bear was because it was non-corrosive. If it stops this problem i will just shoot the corrosive again |
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Well i shot my new Waffen Werks AK-74 today and it went smooth for a hundred rounds. No Keyholes and was pretty damn accurate. But after 100 rounds, this happened. The bolt got stuck and would not close and it was pretty hard to pull back. Finally got it back and round came out. Even though the round was out, the bolt still would not close all the ways so it wasnt the ammo. Took it apart and this is what i found This is the piston head that had some kind of metal fouling other than copper or lead If I understand you correctly, you found metal deposits (which had to be steel, if they weren't copper or lead), or carbon deposits, which were large enough to prevent the piston from entering the gas block fully - after 100 shots. If this is an accurate description of your problem, contact the builder. Something is wrong. |
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Well i shot my new Waffen Werks AK-74 today and it went smooth for a hundred rounds. No Keyholes and was pretty damn accurate. But after 100 rounds, this happened. The bolt got stuck and would not close and it was pretty hard to pull back. Finally got it back and round came out. Even though the round was out, the bolt still would not close all the ways so it wasnt the ammo. Took it apart and this is what i found This is the piston head that had some kind of metal fouling other than copper or lead If I understand you correctly, you found metal deposits (which had to be steel, if they weren't copper or lead), or carbon deposits, which were large enough to prevent the piston from entering the gas block fully - after 100 shots. If this is an accurate description of your problem, contact the builder. Something is wrong. It was lead |
replace the piston?
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Wow apparently these chunks of metal are 6061 Aluminum. Ive had them tested by 2 people and they both said the same thing. To my knowledge there is nothing on an AK made with aluminum. The piston will be stainless steel if US made or hard chromed over steel . All parts, minus stock set, are steel of some type. Any chance the builder left some "crap" in there ? I'm not even sure what a builder would be useing anything made of alumimum for either. Very odd. |
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