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[ARCHIVED THREAD] - PSA Upper issues- Update 8/26 (Page 1 of 2)
Posted: 8/2/2011 7:59:08 PM EDT
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I am having failure to feed and failure to eject on my new Palemetto 16" CHF upper. It's built on a PSA lower and PSA lower build kit.
The neck of each shell is dented has flat spot on it, Ejects at about 1-2 oclock but sometimes at your feet and other times about 4-5 feet away. Sometimes the shell that is feeding get dented and stuck like the bolt is grabbing the side of the shell. Put the PSA lower on my other AR works perfect. ( so lower is OK ) Last shell bolt locks open. Charging handle pulled back bolt face is even with ejection port. Tried stock buffer and H buffer doesn't change issues. Installed new PSA BCG that I have, no change still has issues so BCG Ok? - Also tried adding the black BCM o-ring no change except had some shell get stuck had to take lower off upper to get it out. Cleaned and lubed rifle 3 times. ( I use Slip2000 ) Tried 6 different mags. ( all work with my other AR) but all have same problem with this upper. Tried AE xm193 ammo, Remington .223 , and PMC - all have FTF & FTE issues and all are dented at the neck. What is going on here?????   
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Failure to Extract is usually caused by a weak extractor spring. It can also be caused by out of spec/worn extractor, over gassing, rough chamber, or tight headspace. Look at your cases to see if there are extractor marks on the rim and extractor groove. If not, then look at your extractor and extractor spring. Failure to Eject is usually caused by short stroking. Check your ejector spring to ensure that it is stiff and that the ejector does not have any sharp edges on it. Failure to Feed can be caused by short stroking, bad magazines, a magazine that is not seating properly, or it can be caused by a rough spot on the feed ramp, where the barrel extension and the upper meet. Perform a Short Stroke Check. Troubleshooting Checklist |
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I would call PSA and see if they can swap the new upper.. I mean you just got it and the 2 shells in the chamber pic is abit much.. (esp with them facing opposite directions)..
my new PSA 16" CHF upper started by throwing 1:30-2:30 (about 10 feet) and then after 160 rounds of NATO ammo came around more to 2-4 by the end.. and still 10 feet or so.. |
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Could be an out of spec extractor not holding onto the spent case. There was another member here that had a similar problem (but it was leaving the spent case in the chamber) and it turned out to be the extractor was FUBAR see link below....
http://www.ar15.com/forums/t_3_66/539965_Failure_to_Eject.html&page=1&anc=5171044#i5171044 |
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Photo two tells the tale (dent in the case from being slammed off the back of the ejection port, and bounced back into the action),
Pull the charging handle all the way back, and you will see that the front face of the bolt is retracting back past the back of the ejection port. The face of the bolt should stop in front of the back of ejection port 1/4" to 3/8". Could be that the receiver extension is not threaded in deep enough to the receiver, or that the void in the tube is too long, causing the same problem as well. So it may come down to shorting the tube if installed correctly, shimming behind the buffer and spring to band aid the problem, or getting a replacement tube. To add, if the bolt is locking back on the last round out, then the rifle is stroking correctly and not the stroking being the problem. |
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Photo two tells the tale (dent in the case from being slammed off the back of the ejection port, and bounced back into the action), Pull the charging handle all the way back, and you will see that the front face of the bolt is retracting back past the back of the ejection port. The face of the bolt should stop in front of the back of ejection port 1/4" to 3/8". Could be that the receiver extension is not threaded in deep enough to the receiver, or that the void in the tube is too long, causing the same problem as well. So it may come down to shorting the tube if installed correctly, shimming behind the buffer and spring to band aid the problem, or getting a replacement tube. To add, if the bolt is locking back on the last round out, then the rifle is stroking correctly and not the stroking being the problem. The "Twang Buster" is a good bandaid for the carrier over travel with some of the out of spec RE's with too deep interior dimensions.Only real use Ive seen for one of the things,but it does the trick in alot of cases. http://www.armalite.com/ItemForm.aspx?item=TB2010&Category=93c41860-4ca2-43ee-8ca9-dc09b1a5bf2c |
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Quoted: Pull the charging handle all the way back, and you will see that the front face of the bolt is retracting back past the back of the ejection port. The face of the bolt should stop in front of the back of ejection port 1/4" to 3/8". Could be that the receiver extension is not threaded in deep enough to the receiver, or that the void in the tube is too long, causing the same problem as well. So it may come down to shorting the tube if installed correctly, shimming behind the buffer and spring to band aid the problem, or getting a replacement tube. There have been a few incidences of out of spec receiver extensions the last month or so. Must be maddening for the guys who have this issue. |
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Could be an out of spec extractor not holding onto the spent case. There was another member here that had a similar problem (but it was leaving the spent case in the chamber) and it turned out to be the extractor was FUBAR see link below.... http://www.ar15.com/forums/t_3_66/539965_Failure_to_Eject.html&page=1&anc=5171044#i5171044 Excessive extractor tension can also have an effect on ejection,excessive tension/resistance causes weak or delayed ejection..Ive seen this with CRANE o-rings and some of the HD extractor springs. ETA May or may not have anything to do with the OP's situation,but here is something Ive noted in the past.... Not all bolts and ejectors have the same dimensions either,if the spring tunnel in the extractor is shallow,or the extractor channel in the bolt is shallow,can have an effect and cause extractor spring to coil stack(particularly with non-standard HD extractor springs) or extractor to bind with a CRANE o-ring installed.Both combined can result in a bound up extractor in worst case and cause ejection and in battery feed issues. If you cannot install the extractor with your bare hands and need to use pliers etc.then I would consider lessening extractor tension or inspect parts for proper tolerances.Extractor should be able to move with moderate finger pressure when installed. If you have a Crane o-ring installed and are having extraction or feed issues I would first try running with the CRANE o-ring removed to see if that eliminates the issue. There is also the possibility that the ejector spring is weak,or the ejector is sticking due to fouling/debris etc. causing weak or delayed ejection.If this is the case it will compound the issue in having excessive extractor tension. |
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I can get one more turn on the buffer tube but it will rub the buffer retainer pin ? As I have it now the buffer tube sits on the shoulder of the buffer retainer. I also measured the depth of two other tubes I have- they all have the same inside length.
Why is the shell neck dented like in picture 3 ? |
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Quoted: I can get one more turn on the buffer tube but it will rub the buffer retainer pin ? As I have it now the buffer tube sits on the shoulder of the buffer retainer. I also measured the depth of two other tubes I have- they all have the same inside length. Did you put your PSA upper on your other lowers? |
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I can get one more turn on the buffer tube but it will rub the buffer retainer pin ? As I have it now the buffer tube sits on the shoulder of the buffer retainer. I also measured the depth of two other tubes I have- they all have the same inside length. Why is the shell neck dented like in picture 3 ? How far now is the face of the bolt going back past the back of ejection port with the charging handle pulled all the way back? |
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Quoted: bolt lugs even with the back of ejection port. With the bolt and carrier all the way back on my two PSA uppers are ~ 3/16" to the rear of the bolt catch and are NOT even with the rear edge of the ejection port. It is ~1/8" from the rear edge. Did you check your chamber and see if it is rough? Have you contacted PSA and explained your difficulties? |
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bolt lugs even with the back of ejection port. With the bolt and carrier all the way back on my two PSA uppers are ~ 3/16" to the rear of the bolt catch and are NOT even with the rear edge of the ejection port. It is ~1/8" from the rear edge. Did you check your chamber and see if it is rough? Have you contacted PSA and explained your difficulties? Pictures  
Not sure how to check chamber ? I have email PSA. Thanks |
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Quoted: Not sure how to check chamber? The easiest way to check is with a bore scope, but barring that, you can use a flashlight to see if there are any visible rings along the chamber walls. You can use Flitz polish and apply some on a chamber brush. Using a drill and a section of cleaning rod, you can remove some of the rougher parts off the chamber. See what Palmetto says. |
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Your bolt is able to retract too far...the bolt should stop so as you can see the lugs.....about 1/8 further towards the chamber.....
The buffer tube is too long, or the buffer spring too short. The boltface is being blocked by the rear edge of the ejection port, allowing the case to bounce back into the action instead of being thrown clear. As the boltgroup tries to feed the next round from the magazine the previous case is there to foul things up. Read the post by Dano on how to correct, a few above this post. |
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Your bolt is able to retract too far...the bolt should stop so as you can see the lugs.....about 1/8 further towards the chamber..... The buffer tube is too long, or the buffer spring too short. The boltface is being blocked by the rear edge of the ejection port, allowing the case to bounce back into the action instead of being thrown clear. As the boltgroup tries to feed the next round from the magazine the previous case is there to foul things up. Read the post by Dano on how to correct, a few above this post. Might want to watch this video and see when the case ejects http://www.youtube.com/watch?v=575Q0O41u5s |
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J-3, you posted a great video showing Jered33 what is happening.
Although the video is more for the effects of heaver buffers, and how they can be so heavy that they are on the verge of short stocking (half of the cycles did not have a noticeable rear stall effect), on the video at 41 and 106 seconds when the rifles where using standard buffers and brass case ammo, you can see the dead blow effect of a correctly cycling rifle, and where the spent case will leave the bolt face (on the dead blow effect). Jered33, take another look at these two areas in the video, and realize that on your rifle, the bolt face with your recoil buffer bumper slightly compressing, the face of the bolt will be well behind the back of ejection port with the case not hitting the defector on the way out, but the back of ejection port, and what is causing the dents just above the rims in your causes. To solve the problem, need to either get a replacement receiver extension or shorten the end of the receiver extension so it can be spun into the receiver a few more times while timing up for the buffer retaining pin and stock. To band aid the problem, 3 or 4 fender washers, just a tad smaller OD that the ID of the tube, down before the spring and buffer as spacer shim to take up some of the receiver extension void where it was milled too deep. |
| Actually you can fix this by removing the buffer and spring and drop a quarter down the reciever extension. Then put everything back together. The quarter will act like a shim and keep the bolt from traveling back further than the ejection port. Its a cheap temporary fix, but it is a fix. |
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Not sure why my other two work perfect and they have the same internal length on the buffer tube. My buffer spring is 10 3/4 inches long. I also measured from the back of the tube to the mag well and that seems to be the same on my other ar's as well? Guess I will try some washers.
Not sure I can find a different length buffer tube being the three I have are all the same. |
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Not sure why my other two work perfect and they have the same internal length on the buffer tube. My buffer spring is 10 3/4 inches long. I also measured from the back of the tube to the mag well and that seems to be the same on my other ar's as well? Guess I will try some washers. Not sure I can find a different length buffer tube being the three I have are all the same. Also check/try a different buffer.If the OAL of the buffer is short it will also cause the bolt face to stop further back as its ultimately the limiting factor in travel for the BCG.Most of the variation I have seen in buffer OAL is the polymer damper on the rear of the buffer. I would recommend using a known quality buffer in the gun....all buffers are not created equal....I prefer to buy buffers from LMT,Colt or BCM so I know what Im getting. As I said before if you have the o-ring installed on the extractor spring,remove it and see if that helps as well. |
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Quoted: As I said before if you have the o-ring installed on the extractor spring,remove it and see if that helps as well. I thought he did that, as he said adding the 'O' ring would cause the case to stick and would only come out by taking the upper apart. Hey OP, has Daniel @ Palmetto gotten back to you? |
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The video shows the case is ejected before the carrier/bolt is anywhere near the back. The depth of the tube has nothing to do with the ejection of the case. I would look elsewhere for the problem.
Only thing I would worry about a tube being to deep would be if the back of the carrier key was hitting the raised portion of lower receiver. |
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I did remove the o ring and joe at PSA sent a return tag for it. I also tried two differnt buffers. Good. Something is causing the cases to stay on the bolt face too long and since this is a new upper, let PSA handle this. Best advice . Ill let everyone know how it turns out. |
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As I said before if you have the o-ring installed on the extractor spring,remove it and see if that helps as well. I thought he did that, as he said adding the 'O' ring would cause the case to stick and would only come out by taking the upper apart. Hey OP, has Daniel @ Palmetto gotten back to you? Somehow missed that....need to pay better attention and shut up. Yeap,if PSA is willing to do it I'd certainly send that pesky rascal back. |
| I would first check the ejector spring. It's a simple test. Use your fingernail to press in on the ejector. It should move a little, but be very stiff. It should also bend your fingernail a little. There two springs in your weapon that look similar and could get easily confused. One is used in the takedown pins and the other is used in the safety selector and the ejector. The takedown springs are much weaker, and if it is mistaken for an ejector spring you get the problem that you are describing. As for the BCG too far back in the receiver, that is a different issue. That too could be and out of spec buffer spring. First rule is to check springs first. |
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The video shows the case is ejected before the carrier/bolt is anywhere near the back. The depth of the tube has nothing to do with the ejection of the case. I would look elsewhere for the problem. Only thing I would worry about a tube being to deep would be if the back of the carrier key was hitting the raised portion of lower receiver. J3, take another look at the video you posted, What is is showing is buffer weights, and how they can effect ejection with both steel and brass case ammo.. The two time parts that I noted where of brass case ammo and standard buffer, which shows the base leaving the bolt face just about the dead blow effect of the buffer (bolt face stopping in front of the ejection port). With his bolt face flush when the charging handle is pulled back, and behind the back of ejection port when the rifle is under self recoil (buffer bumper defecting), the spent case is leaving the bolt face with the bolt face behind the ejection port, and why in his second photo of his first post, you can see the tell tale case dent mark of the brass slamming off the back of the ejection port (then being defected forward back into the action in the other photo's. The fix to the problem is easy, get the Bolt face to stop the correct distance in front of the back of ejection port, be it shorting the tube front so it can be threaded in a few more turns, or just shim out behind the spring and buffer as a band aid instead. |
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We disagree on the video. I see the case leaving long before the bolt is anywhere near the rear. Buffer used makes no real difference. OP even stated he tried an H buffer.
All of the ARs I have stop with the bolt front even with the rear of the ejection port and they function fine. The material on the buffer does not compress that much. Only barrel I had that dropped them at your feet on occasion had a junk chamber and an incorrectly located extension. The OP said he put the lower on another upper and it functions fine. Put the PSA lower on my other AR works perfect.
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| The Twang Buster actually cased me some issues on a couple of rifles I checked out... It stopped the bolt from reaching its full travel by stopping the buffer short and not letting the bolt lock on the last round....Its how the buffer tube is machined some have a relief on the back side and some are flat.. the ones with the relief is where the spring sits and when you install the twang buster it stops the spring from seating where it needs shorting it about 1/4 inch.... |
| Regarding the video posted, if you stop it at 43 and 107, the case is off of the bolt face when the bolt is still 1/2 inch in front of the rear edge of the port. I wonder if the reason that cases hit the rear edge of the port is not because of where the bolt stops, but because of the rearward velocity of the bolt. When the rifle is fired, the case is moving in two directions at the same time, rearward first , and then rearward and outward. If it is moving rearward at too great a speed, the rear end of the case will hit the rear edge of the port because it has not had the time to simultaneausly move outboard far enough to clear the rear edge of the opening. Just a thought. |
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Emailed them lots of times for an update and this it the only response I got today.
"Your upper was cleaned thoroughly and was then test fired with 180 rounds of M855 and M193. We experienced no failures during testing." Thanks, Kyle Chanko Palmetto State Armory Guess I'll look it over good when it shows back up and see what it does for me. I cleaned that upper three times and it still was having issues? Thinking there is more to the story. |
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Quoted: Emailed them lots of times for an update and this it the only response I got today. "Your upper was cleaned thoroughly and was then test fired with 180 rounds of M855 and M193. We experienced no failures during testing." Thanks, Kyle Chanko Palmetto State Armory Guess I'll look it over good when it shows back up and see what it does for me. I cleaned that upper three times and it still was having issues? Thinking there is more to the story. There might be more to the story, but if the upper works when you get it back, does this matter? Glad that the turn around time is ~ two weeks. |
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UPDATE
I got my 16" CHF upper upper back from PSA today, I took it to the range and had 6 FTF and 4 where it caught in the ejection port , the necks of each shell was dented as before and ejection was at 1 oclock to 5 oclock and from 8 feet away to at my feet very eratic (Tried stock buffer, H buffer, and ST-T2 buffer no change.). I was using xm193 that i use in my other AR's . After 100 rounds I swapped out the PSA lower I had to a different lower and the upper still was having issue (shot another 100 with this lower( has BCM buffer tube and BCM buffer spring in it) and had same issues). Both lowers work great on my other AR I have, also I was using 4 different pmags that I use in my other AR with no issues . Installed a BCM bolt no change. At this point I'm thinking its a Its a chamber or feedramp issue? Really have no clue shouldnt be this hard. 
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| I couldn't find where you tested a different bolt carrier group, or bolt. Try a known working bolt, if that works, contact PSA and ask to exchange bolts. Ditto with the carrier if that's the problem. If the problem persists with a known good bolt and carrier, you just eliminated that source. And since you eliminated the lower before, you know it's got to be the gas system or specs on hte upper, and you need to tell PSA that you don't always shoot M855 and their rifle should work with M193. Speaking of which, did you try M855? |
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I'm usually a PSA type guy (aka fan-boy).. (mine has been great for me) (FWIW.. I ordered my upper from PSA mid-July)
sounds like you got a DUD dude.. you confirmed the LOWER is GTG.. just check the BCG in the other upper you got.. to see if you get the same results with your GOOD upper.. then you'll know if its your BCG.. if it is have them send you a PREMIUM BCG only.. (thats what came with my HF upper) again, sorry for your issues.. |
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No sure if any of this was mentioned, sorry I didn't read the whole thread, but It sounds slightly over gassed to me.
The more violent action is bouncing the cases off the port door and back into the receiver causing the dents and stove pipes. It could also not be letting the mag recover enough before the BCG is flying forward again causing your FTF. The gas port in the barrel might be slightly over sized. A heavier buffer might help, I know you said you tried an H and the ST-T2 but IIRC they are equivalent in weight, I would go to an H2 or H3 buffer and see what happens. Just my .02. 
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| No new updates. I got it back from PSA with the same issues. I have tried to contact them about this but have not got any response. I have emailed, IM'd and called with no luck. Posted a customer service? In there industry forum and looks like they removed it. Seems like they don't want any bad PR. |
[ARCHIVED THREAD] - PSA Upper issues- Update 8/26 (Page 1 of 2)
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