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Hello everybody, so the biggest reason for me joining this forum is to try and get some help/ advise regarding my AR-15, a little backstory, the guns 3 years old, my father and I built it but never took it out, finally yesterday I broke it in, now during this process, I was having some weird jamming issues, it wasn't jamming every time it cycled, sometimes it would jam after a few rounds, sometimes it would jam after a whole 30rnd mag, or it would jam simply by closing the bolt from putting a new mag in. so after searching through youtube and other forums here, I am, ill try my best to break it down as simply as I can because I am not a gunsmith nor that great with these, this is my first build.

'I also didn't take any of the spent casing back home with me. I didn't know i should've until I came home and did some homework'


TL;DR a lot of brass transfer on the internals of the rifle, I'm thinking possibly my extractor head is ripping the casings out improperly.
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so picture one, this is what the jam looks like every time, it doesnt fully go into battery, trying to pull it back with the charging handle never worked, nor pushing in the forward assist, the only thing that cleared this jam was separating the upper and lower receivers and pushing the back of the bolt into the chamber, after that, the charging handle still wouldn't pull it out so we had to pull the hammer back, put the receivers back into place and then fire the round. "I know it's not the safest option but that's why we went into the middle of nowhere" plus I think it's odd to have that much scoring onto the shell deflector? we shot about 100 rounds. 'again this is my first build, I thought the random jamming was just because it needed to be broken in'
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These next few images are just different angles of the chamber what threw me off was the amount of brass buildup right at the entrance of the chamber, that seems like an excessive amount.
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Theres a bit of scoring around the entrance aswell. I'm not sure if that's normal or not.
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some more brass scraping.
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again I think this is just way too much brass scuffing onto the extractor as well.
09.jpg

I also took apart the extractor head to take this picture as well, brass was able to make its way inside this little valley deal. while I was on youtube trying to find people with similar issues I came across a guy that had a similar deal, except his was jamming with every single round, he said if you take off this o-ring then it will stop doing it, which in my mind makes sense, it seems like my extractor is aggressively slamming into the back of the casing and yanking it out of the chamber causing the brass transfer on the shell deflector, ejection port, and the chamber.
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anyways thank you all for the possible help, hopefully, this is an easily fixable situation, I have not taken that o-ring out until I get more proof of it being the problem, hopefully, she can be back at the range soon! and yes I did do a very thorough cleaning after taking all these pictures lol.
 

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There are people more expert than I am that will be along shortly. Just wondering: What ammo are you firing? Reloads or Factory?. Without seeing what you are doing, when you say "jamming" are you saying the rounds are not fully chambering? Does the bolt go fully closed easily (into battery) when the rifle is not loaded?

One observation is that the bolt looks to be very dry to me. The pin that holds the bolt inside of the bolt body needs lubrication. It has to turn slightly when the bolt goes fully into battery to engage the locking lugs. You don't want to 'over-do it' but it should be lubricated. The entire bolt should be lightly oiled. Don't go hog wild, because too much lube will make the rifle sluggish and collect carbon.
 

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Disconnector spring installed upside down or a defective disconnector. If the spring is not installed correctly, the disconnector will not hold the hammer back far enough during the hammer/trigger cocking/reset causing the hammer to drag on the bottom of the bolt carrier when the BCG cycles forward after firing a round.

Leave that O ring in the extractor. It is there to increase the tension on the extractor. Also. The brass shavings are from too sharp of edges on the extractor claw. When the bolt rotates during lock up and unlock, any sharp edges on the extractor claw groove while shave brass from the cartridge cases extraction rim. Try stoning the extractor’s claws edges. If you do not have a stone to fit the groove, first use 600 grit, followed by 800 grit silicon carbide paper wrapped around something to polish a small radius to the sharp edges. You just what remove any sharp edges. FYI. The extractor is made from ISO 8620 case hardened. Do not use any files. They will only scratch the metal causing more brass shaving.

The brass scuff marks on the upper receiver brass deflector are normal. Use a good ammonia based copper solvent bore cleaner and a soft rag to remove the brass scuffs. Sweets 7.63 is a very high ammonia content bore cleaner/copper solvent. Hoppies, Benchrest bore cleaner will work also, but its ammonia content is not as high, but it is easier to find in a store.
 

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There are people more expert than I am that will be along shortly. Just wondering: What ammo are you firing? Reloads or Factory?. Without seeing what you are doing, when you say "jamming" are you saying the rounds are not fully chambering? Does the bolt go fully closed easily (into battery) when the rifle is not loaded?

One observation is that the bolt looks to be very dry to me. The pin that holds the bolt inside of the bolt body needs lubrication. It has to turn slightly when the bolt goes fully into battery to engage the locking lugs. You don't want to 'over-do it' but it should be lubricated. The entire bolt should be lightly oiled. Don't go hog wild, because too much lube will make the rifle sluggish and collect carbon.
Im using factory, the brand is red army standard 56 grain but yes when it jams, it doesnt fully chamber the round, when the rifle is unloaded it works fine, multiple function tests and everything seems okay. at the time of firing it was pretty oiled, I may have not oiled the right areas of the bolt though. thank you for the suggestion.

Disconnector spring installed upside down or a defective disconnector. If the spring is not installed correctly, the disconnector will not hold the hammer back far enough during the hammer/trigger cocking/reset causing the hammer to drag on the bottom of the bolt carrier when the BCG cycles forward after firing a round.

Leave that O ring in the extractor. It is there to increase the tension on the extractor. Also. The brass shavings are from too sharp of edges on the extractor claw. When the bolt rotates during lock up and unlock, any sharp edges on the extractor claw groove while shave brass from the cartridge cases extraction rim. Try stoning the extractor’s claws edges. If you do not have a stone to fit the groove, first use 600 grit, followed by 800 grit silicon carbide paper wrapped around something to polish a small radius to the sharp edges. You just what remove any sharp edges. FYI. The extractor is made from ISO 8620 case hardened. Do not use any files. They will only scratch the metal causing more brass shaving.

The brass scuff marks on the upper receiver brass deflector are normal. Use a good ammonia based copper solvent bore cleaner and a soft rag to remove the brass scuffs. Sweets 7.63 is a very high ammonia content bore cleaner/copper solvent. Hoppies, Benchrest bore cleaner will work also, but its ammonia content is not as high, but it is easier to find in a store.

I can see that happening, maybe that's what caused the bolt to be stuck closed, it could've been just jammed on the hammer. i don't see any markings on the hammer though, the trigger is an all in one deal but ill take it apart and check out that spring tomorrow. thank you for the reply, ill send the link to my dad, he might have a stone.
 

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Im using factory, the brand is red army standard 56 grain but yes when it jams, it doesnt fully chamber the round, when the rifle is unloaded it works fine, multiple function tests and everything seems okay. at the time of firing it was pretty oiled, I may have not oiled the right areas of the bolt though. thank you for the suggestion.
You mite have a chamber that was cut just a tad short, maybe, but the only way to test that is with a GO head space gauge. These are made of steel so the will not compress like a brass cartridge case. If you do not have a head space gauge, you could find a local gun smith who has one to check the chamber’s head space. If not, look online for 223/5.56 GO head space gages for sale. I just looked by typing 223/5.56 GO head space gauges and found dozens for sale, both new and used. A new Forster Products sell for about $30.00.
 

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With the exception of the bolt type of steel (Either Carpenter 158 or the now favored SAE 9310), the bolt carrier along with all the internal parts, (hammer, trigger, safety, etc.) are made of SAE 8620. The hardness of the bolt carrier and hammer are the same, so any ware marks will be only after many cycles of the BCG. The only ware you will see first is the eventual ware of what ever coating is used on either parts. Usual coating for MIL spec will be manginess phosphate which is very hard waring. Cheaper would be a salt type bluing which is not hard waring.
 

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Discussion Starter · #7 ·
With the exception of the bolt type of steel (Either Carpenter 158 or the now favored SAE 9310), the bolt carrier along with all the internal parts, (hammer, trigger, safety, etc.) are made of SAE 8620. The hardness of the bolt carrier and hammer are the same, so any ware marks will be only after many cycles of the BCG. The only ware you will see first is the eventual ware of what ever coating is used on either parts. Usual coating for MIL spec will be manginess phosphate which is very hard waring. Cheaper would be a salt type bluing which is not hard waring.

I can't remember which type of bolt I purchased, it been a while but that makes sense on how it wouldn't show any markings, ill check that in the morning, I hope its just something small like that, as far as the chamber goes, let's say my chamber was cut a bit short, probably the best solution would be just to purchase a new barrel?
 

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I can't remember which type of bolt I purchased, it been a while but that makes sense on how it wouldn't show any markings, ill check that in the morning, I hope its just something small like that, as far as the chamber goes, let's say my chamber was cut a bit short, probably the best solution would be just to purchase a new barrel?
Don’t replace the barrel just yet. Like I suggested to first see if there is a local gunsmith, and I emphasize a real GUNSMITH, not a gun plumber, to check your chamber. It could also be a ruff chamber that needs polishing.

If indeed the chamber is short, then replacing the barrel is the best option. The reason is that unless you have the original chamber reamer, it is a 50/50 or so chance that the reamer is slightly under or over sized compared to the chamber in your rifle. If the reamer is slightly over sized, and I mean no more the .001”-.0015, then cutting and pushing the chamber shoulder foreword would not be a problem, but if the reamer is under sized, trying to recut the chamber would only cause an irregularity in the barrel’s chamber.

I forgot to add that head space is checked with bolt in place. I have seen some bolt in the past were the recessed bolt face was cut not deep enough. That can give impression of a short chamber. Again, this can be checked with a head space gauge.
 

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The markings at the front of the ejection port are interesting. None of mine have ever scored the front like that-almost looks like over gassing. Deflector is common, I just put a piece of black tape on mine, stays put stops the brass transfer.
That gun seems very dry, very dry.
A Go-No go gauge should be used on any home build, my opinion.
 

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My nephew built a rifle a couple years ago and was having jamming issues. After looking at it for a bit with the handguard off it looked to me that the gas tube was not perfectly straight. After taking the block and tube off I seen a bit of a rub on one side of the gas tube where it enters the gas key. I set it to where it looked perfectly straight to me. I also backed the buffer tube out 1 rotation as it looked a bit to far in after comparing to a couple others. Problem solved, although from your picture the end of the tube that enters the gas key looks good.
A question I have is what weight buffer are you running and where is your brass going. My 1st rifle was ejecting to 2 o'clock with a standard buffer and the recoil impulse felt hard. I went to an H2 buffer and that changed the brass ejecting to 3 o'clock and softened the recoil impulse a little. My barrel has a mid length gas port.
Also I would not suggest taking apart a drop in trigger which could void any warranty they offer. If you think there is a trigger issue call the manufacturer and talk to them, they may have you mail it in for them to check it out.
 

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My nephew built a rifle a couple years ago and was having jamming issues. After looking at it for a bit with the handguard off it looked to me that the gas tube was not perfectly straight. After taking the block and tube off I seen a bit of a rub on one side of the gas tube where it enters the gas key. I set it to where it looked perfectly straight to me. I also backed the buffer tube out 1 rotation as it looked a bit to far in after comparing to a couple others. Problem solved, although from your picture the end of the tube that enters the gas key looks good.
A question I have is what weight buffer are you running and where is your brass going. My 1st rifle was ejecting to 2 o'clock with a standard buffer and the recoil impulse felt hard. I went to an H2 buffer and that changed the brass ejecting to 3 o'clock and softened the recoil impulse a little. My barrel has a mid length gas port.
Also I would not suggest taking apart a drop in trigger which could void any warranty they offer. If you think there is a trigger issue call the manufacturer and talk to them, they may have you mail it in for them to check it out.

I see, I am pretty new at building them but everything yall said in the thread ill just go down the list and see what works. thank you!

What gas system?
What buffer?
Lube the poor thing-if lube hits you in face first shot-GTG

I'm not sure which buffer tube and gas system it has like I said it was actually built three years ago and we didn't save any of the packagings for parts. but you are 100% right on the lube, however, I did clean the bolt before I took these pics, when I brought it to my local gun shop he told me the same thing, I was being too conservative with the lube.

The markings at the front of the ejection port are interesting. None of mine have ever scored the front like that-almost looks like over gassing. Deflector is common, I just put a piece of black tape on mine, stays put stops the brass transfer.
That gun seems very dry, very dry.
A Go-No go gauge should be used on any home build, my opinion.
i think we used one when we built it, but i cant really remember, its been a long time.

Is Red Army ammo steel cased?

red army is steel cased, I should edit that because I just noticed a while ago that I was using rounds my father gave me when we built it, not the red army. that was my mistake.

Don’t replace the barrel just yet. Like I suggested to first see if there is a local gunsmith, and I emphasize a real GUNSMITH, not a gun plumber, to check your chamber. It could also be a ruff chamber that needs polishing.

If indeed the chamber is short, then replacing the barrel is the best option. The reason is that unless you have the original chamber reamer, it is a 50/50 or so chance that the reamer is slightly under or over sized compared to the chamber in your rifle. If the reamer is slightly over sized, and I mean no more the .001”-.0015, then cutting and pushing the chamber shoulder foreword would not be a problem, but if the reamer is under sized, trying to recut the chamber would only cause an irregularity in the barrel’s chamber.

I forgot to add that headspace is checked with bolt in place. I have seen some bolt in the past were the recessed bolt face was cut not deep enough. That can give impression of a short chamber. Again, this can be checked with a head space gauge.

thank you for all your replies, you have helped a ton, I took it to a local gun shop today and they told me that the issues im experiencing are common and advised me to use better ammo, as well as pointed out i am severely under lubing the gun, he also told me to get some steel polish and polish up the chamber, if none of the somewhat free remedies yall have given me work, then i will take it to a professional smith. thank you again!
 

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Under lube is #1 reason AR won't run.......Watch the youtube video of Larry Vickers submerging an AR in motor oil-slap mags in and runs like a clock....Use good lube-ALG/SLP2000/Lucas.
 
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