first time taking AR out . Jamming issues, Advice ?

All my nea rifles run perfect from day one. Psa was not setup right for the barrel length. But as I have come to realize over and over again nea is #### and I must have the only 3 that where any good.
 
I'm not going to lie. I don't understand how the buffer or buffer spring would cause a failure to extract... The bolt appears to be cycling fine, and it is stripping off rounds so I would have started with borrowing a buddies bolt and bolt carrier group.
 
mustang979 said:
I'm not going to lie. I don't understand how the buffer or buffer spring would cause a failure to extract... The bolt appears to be cycling fine, and it is stripping off rounds so I would have started with borrowing a buddies bolt and bolt carrier group.
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When it's over gassed and the dwell time is so short the case is still held under pressure so the extractor Dose not have enough strength to hold or pull the case. The bolt releases of the case head and cycles back stripping another round. There are some good explanations in the first few pages.
 
Kidd X said:
A heavier buffer, heavier spring or heavier buffer and spring all work to keep the action closed longer, so that pressures drop and cases contract before the BCG tries to extract and cycle. A heavier buffer or spring in a longer barreled rifle isn't unusual either and for the same reasons. I personally run T2 buffers in my AR's from 11.5" to 16". Gives a very smooth feeling action when it cycles.

The goal is to try and achieve the same "cycling" energy as the classic 20" rifle length gas system guns. The old traditional has a comparatively low port pressure of about 19K PSI which is why the 20" guns cycle very smooth and don't have an aggressive recoil impulse. The added weight and length also helps but we're talking gas systems here. The shorter carbine gas system of the M4 is a compromise and was partially designed to be gassed as a reliability feature. The M4 or any carbine gas AR is still over gassed(33K PSI), just not as much as some of the shorter guns like 11.5"/10.5"/and shorter(depending on maker the gas ports on the short guns can be crazy large causing insane pressures). Add in the gas port variances between manufacturers and pressure differences between ammo(5.56 vs .223) and you can end up with a very over gassed gun or an under gassed gun. Both of which won't run properly. The mid length gas system was introduced as a mechanical(and fixed) method of trying to achieve the golden 20" AR "cycling" energy/pressures. With a 14.5" or 16" barrel there's no need to have the gas port so far back from the muzzle. Moving the port forward reduces dwell time, the time in which the BCG is receiving gas pressure before the bullet exits the barrel and breaks the seal. By reducing dwell time you are also reducing PSI. We know that the carbine gas system is already over gassed. So we can play with the amount of gas and the amount of time the BCG gets that gas in an attempt to find that "low" pressure sweet spot that still provides reliable cycling without beating the life out of the gun or shooter.

There are manufacturers who offer a mid length gas system on barrels as short as 12.5". That puts the gas port less than two inches from the muzzle! In such a case the gas port would be enlarged to allow a rapid and high volume flow of gas over a very short period of time to ensure reliable cycling(short dwell time) as the bullet has almost left the barrel breaking the seal and eliminating all gas pressure. Again there is a sweet spot between gas system length, barrel length, and gas port size. Here's the easy and reliable route/numbers, some barrel lengths are workable with two gas system lengths.

18" and up- Rifle length gas system
18"-14.5" Midlength gas system
14.5"-10.5" carbine gas system
Under 10.5" Pistol length gas system(if the gun is tuned and built properly)
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An excellent overview of the gas system of the different AR-15 systems.

As a follow up question to Kidd - Is there a general observation to tell if your AR gas system is optimized as far as recoil, brass extraction, gas fouling in the BCG etc? My AR-15 14.5 inch barrel is running fine with no failures but is there a way I can tell if it's optimized (in the sweet spot). Maybe extraction angle and distance from ejection port?

Or should I just leave well enough alone?
 
lavino said:
I am kinda new to AR too so plz forgive me if I am not making sense ;) I heard some people suggested switching to a slightly heavier buffer in case of overgas situation. Would this be another viable approach too or is there any advantages or disadvantages to this?
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After Reading KIDDs great info, I would suggest that if overgassing is the issue, fix the over gassing first. IN my experience treating the symptoms with band aids causes as many problems as it solves until you are ready to throw the gun in the garbage, or sell it, as was the case with the OP and the last owner.

My gun was short stroking and getting stoppages where it was failing to pick up a new round after ejecting the case and wouldn't lock back on an empty mag. 10 out of 10 people I spoke to agreed it was short stroking due to under gassing, despite using 5.56 ammo. The solutions that people recommended were all over the map, including cutting buffer springs, buying new buffer, buying new BCG, new barrel etc. This gun ran great for ~25,000 rounds and starting undergassing. After talking to the weapons tech at Colt, $4 worth of gas rings and $14 for a new mil spec gas tube and she runs like new.

The problem was the gas tube and the solution was the gas tube. Those pig tails look cute.
 
PSE said:
An excellent overview of the gas system of the different AR-15 systems.

As a follow up question to Kidd - Is there a general observation to tell if your AR gas system is optimized as far as recoil, brass extraction, gas fouling in the BCG etc? My AR-15 14.5 inch barrel is running fine with no failures but is there a way I can tell if it's optimized (in the sweet spot). Maybe extraction angle and distance from ejection port?
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A general rule is to observe your ejection pattern. The so called ideal location is somewhere around 4 o' clock to 5 o' clock for ejected brass. If your brass is ejecting and landing at 3 o' clock or further forward then the gun is likely over gassed. If you have another AR to compare yours to you should be able to feel the difference in recoil impulse. An over gassed gun will recoil then slam into your shoulder as the BCG and buffer bottom out in the tube. Also, have a look at the polyurethane tip on the buffer itself. If it looks mushroomed or is showing signs of mushrooming then your action is cycling too fast and too hard. Possible culprits for this are: Over gassed, worn recoil spring, buffer too light, spring too light.

I'm betting your 14.5" is a carbine length gas system?

Cameron SS said:
After Reading KIDDs great info, I would suggest that if overgassing is the issue, fix the over gassing first. IN my experience treating the symptoms with band aids causes as many problems as it solves until you are ready to throw the gun in the garbage, or sell it, as was the case with the OP and the last owner.

My gun was short stroking and getting stoppages where it was failing to pick up a new round after ejecting the case and wouldn't lock back on an empty mag. 10 out of 10 people I spoke to agreed it was short stroking due to under gassing, despite using 5.56 ammo. The solutions that people recommended were all over the map, including cutting buffer springs, buying new buffer, buying new BCG, new barrel etc. This gun ran great for ~25,000 rounds and starting undergassing. After talking to the weapons tech at Colt, $4 worth of gas rings and $14 for a new mil spec gas tube and she runs like new.

The problem was the gas tube and the solution was the gas tube. Those pig tails look cute.
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I always suggest to people to start with the cheapest fix first, after properly diagnosing the problem ;)
 
Kidd X said:
A general rule is to observe your ejection pattern. The so called ideal location is somewhere around 4 o' clock to 5 o' clock for ejected brass. If your brass is ejecting and landing at 3 o' clock or further forward then the gun is likely over gassed. If you have another AR to compare yours to you should be able to feel the difference in recoil impulse. An over gassed gun will recoil then slam into your shoulder as the BCG and buffer bottom out in the tube. Also, have a look at the polyurethane tip on the buffer itself. If it looks mushroomed or is showing signs of mushrooming then your action is cycling too fast and too hard. Possible culprits for this are: Over gassed, worn recoil spring, buffer too light, spring too light.


I'm betting your 14.5" is a carbine length gas system?



I always suggest to people to start with the cheapest fix first, after properly diagnosing the problem ;)
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Good info - I will check this out on my 14.5 inch AR - Thanks for the knowledgeable reply
 
heliace said:
Buy a mini 14...eats everything and you can go hunt with it.
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HAHAHAHAHA.... No.

Mangun said:
Try to install the “o”ring around the extractor spring on the bolt I found that because the bolt carrier cycled so fast with short barrel the extractor would ride over the shell and not eject spent shell Adding additional preasure on extractor soved my problems

https://www.bravocompanyusa.com/BCM-Extractor-Spring-Uprade-Kit-p/bcm-exspring-1.htm
This is a link to an example of what I am talking about
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The O ring was installed in M4 rifles as a bandaid solution to the over gassed guns failing(rarely but it was happening) to extract and/or tearing cases. The reason they tear the cases(or jump the rim) is because they're trying to extract too early in the firing cycle. A heavier buffer would be a better solution as has been mentioned already.
 
Kidd X said:
HAHAHAHAHA.... No.



The O ring was installed in M4 rifles as a bandaid solution to the over gassed guns failing(rarely but it was happening) to extract and/or tearing cases. The reason they tear the cases(or jump the rim) is because they're trying to extract too early in the firing cycle. A heavier buffer would be a better solution as has been mentioned already.
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Although I see this suggested a lot, I find that heavier buffers don't tend to help much (if at all) if the rifle is grossly over-gassed . And when they do help.....the upper probably wasn't that over-gassed to begin with. ;)

An extractor o-ring (if the extractor doesn't already have one) is the cheapest thing to try.

I'm fond of adjustable gas blocks, because they solve the problem closest to the source (oversized gas port) but admittedly they are not the cheapest solution :(
 
*MALICE* said:
Although I see this suggested a lot, I find that heavier buffers don't tend to help much (if at all) if the rifle is grossly over-gassed . And when they do help.....the upper probably wasn't that over-gassed to begin with. ;)

An extractor o-ring (if the extractor doesn't already have one) is the cheapest thing to try.

I'm fond of adjustable gas blocks, because they solve the problem closest to the source (oversized gas port) but admittedly they are not the cheapest solution :(
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If the cheap, fast and easy way were ever the right way, it would just be called 'the way'.
 
One thing i noticed about neas is usually very weak ejector springs. If you can drepress it with you finger with moderate to easy effort, then thats the culprit. Ymmv
 
Kondor said:
The gun would fail to extract thankfully a spent round and tried to chamber a live one and would jam the projectile into the cartridge costing me ammo as well
or is there somthing potentially wrong with the extractor or lacking proper lubrication ?
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When I built my shorty AR I had similar problems...fired case wouldn't extract, then a double feed. What solved it was a 'donut' under the extractor. It has run perfectly ever since. If it isn't _hard_ for you to move your extractor manually, this could very well be your problem.
 
I had the same problem with a 7.62x39 NEA 7.5. These things are WAY over gassed! Ammo was being thrown at the 1 or 2 clock position, when it extracted. I tried upgraded extractor springs, heavier buffer, it got better but not perfect. I finally went with an adjustable gasblock, dialed the gas down and way it went. No problems now. I used a Superlative adjustable gasblock from CTCS. Pretty easy to swap the old one out. The only real problem i had was the OEM crush washer got deformed and I needed to cut it off. So if you are going to go down this route get a spare crush washer for your brake.

https://ctcsupplies.ca/collections/...djustable-gas-block-bleed-off-solid-melonited
 
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