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I finally got my new PF 16" complete upper in the mail this weekend. I put it on the lower I built and went through the break in process that PF recommended. After shooting a few single shots with it, I loaded the mag with 3 shells. After the first shot, it ejected the empty but did not load the 2nd round. The 2nd round got caught and damaged the cartridge pretty bad.
Bear in mind, this is my first AR and I am a complete noob so I do not know much about it. I'm sure this problem has occurred many times before. Is it something that I have done when I built the lower? Any input would be greatly appreciated. Let me know if you all need to know anything else to help me fix it.
I tried to post some pics so hopefully they uploaded.
Thanks in advance.
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CT95:
You need to look at the Troubleshooting forum. There are several recent threads on your problem.
LR55
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What mag are you using? I had a similar problem with ASC mags. I changed to Alexander Arms and haven't had a single problem since.
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Make sure the mag is cleaned and then oiled well.
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What buffer are you using?
Never walk away from home ahead of your axe and sword. You can't feel a battle in your bones or foresee a fight. -The Havamal
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What length gas? Adjustable or nonadjustable gas block? What length buffer tube and weight of buffer? Who's mags?
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07-27-2016, 06:01 PM
(This post was last modified: 07-27-2016, 06:16 PM by rabiddawg.)
One of mine started doing that. I ended up changing to an adjustable gas block but the cause was leakage at the block. Which equates to under gassed
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I am using the asc 10 round mags with the blue. The buffer was a complete kit I bought, it's a PSA freedom buffer tube assembly and I put it on a Daniel defense collapsible stock.
The upper is a PF Neptune EL v-1 so it's non adjustable gas block. I can't imagine it being under gased with it coming from PF but you never know
I can try getting a couple of the AA mags and trying them. I loaded up my ASC mags earlier in the week to let them sit, I saw where someone said that May help in another forum.
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I want badly to agree with you that it isn't undergassed because I am a pf fan. I own two pf products.
That being said, I know that one of my AA guns started intermittently started failing to feed the next round. However, it always locked back on the last round. I did all the ez things first. Disassembled the bolt and cleaned everything; no change. I changed the ejector, extractor and their springs; no change. Then I removed the hand guard and saw a slight bit of fouling around the gas block and tube. I ordered a syrac adj. gas block, installed it, bedded it and the tube with loctite. No more problem.
If it's not the upper, about all it could be is the buffer weight, spring strength or interference sometwhere.
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Post some pics of your malfunction.
This is a thread I started about mine. See if anything sounds or looks similar.
http://www.65grendel.com/forum/showthrea...-With-Pics
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Rabbidawg, the first picture in that thread is exactly what the malfunction looks like in my rifle. I will shoot it again this weekend to try and get a better understanding of what's going on.
I don't know anyone that has an AR so I can't switch the lowers to see if that helps. I could try to get a different buffer to see if that helps if you all think it may. I'm not familiar workin on uppers so I don't think I'd want to start tinkering on the gas tube stuff especially with it being brand new.
I'll post pics this weekend of exactly what's going on and maybe that will give you all a better understanding of what I should do.
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07-30-2016, 03:00 AM
(This post was last modified: 07-30-2016, 03:04 AM by rabiddawg.)
Get a weight on your buffer and give Mark a call or email. I'm sure he will take care of you.
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Failure To Feed with bolt over base
That's where the indentations on the brass are coming from when the bolt lugs ride over and smash the cartridge against the feed ramps.
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Any ideas what's the most probable cause LRRPF? Mags? Gas? Or buffer. Or any of the above. I haven't had a chance to check weight on buffer. Any ideas what it needs to be with this upper?
I'll oil the mags good then shoot and post pics to see if it still does this or if it helps
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Update:
I weighed the buffer and it weighs right at 2.95 oz and spring is 10.5 inches long.
I ordered a few elander mags from AA and am waiting to see if they help.
Also, I contacted Mark at PF to see what he has to say about it, whether or not it mY be a gas issue since he did the upper.
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My first guess would say that it is a gas / buffer issue. It sounds like the bolt is short-stroking and not going all the way to the rear thus it doesn't pick up the next round at the back of the mag; but instead catches the next case after the base creating the FTF BOB that was mentioned above.
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If a rifle is at the edge of being under gassed, there are a few things that I have experienced that will cause a short stroke.
No lube in the buffer tube.
A sharp edge on the hammer dragging on the bolt.
The rings on the bolt not aligned properly.
A few more rounds to finish the break-in.
As already discussed - the gas block not aligned properly or leaking.
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I switched my carbine lower with an MP lower that is a rifle stock and rifle buffer. I shot his lower with my upper and it cycled perfectly. I did not get a chance to put my lower on his mP223 upper.
Conclusion: since my buddies lower worked on my upper and it cycled correctly, it tells me that it is not a magazine or a gas issue with my upper(unless it being a rifle buffer makes a difference)
My carbine lower with my upper: after shooting a round without anything in the magazine, the bolt does lock back
Does this sound like a buffer problem with my lower? Can't be a gas or mag issue since it works on his lower right, or am I missing something.
Thanks for helping me work this out folks.
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Update:
So I just received a 24round e-lander mag from AA, I bought some 10rounders too but they were out of stock. Shot about 10 rounds through it and my gun cycled them perfectly it looked like.
So a couple questions I have, What are the reasons why the ASC mags do not cyle correctly in my lower but will in my buddies rifle buffer lower? Is there anything I can do to make the ASC Mags work better?
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Thats a good question on the mags Clint.
I use some 10 round Cproducts defense mags and some 5 round ASC mags I got from PF and I have yet to have a feed issue with either one of these mags that was a mag issue, my issues were gas related.
These mags are on their second upper but same lower and the lower is set up with rifle length buffer tube and SCS from JP.
So maybe its your carbine buffer is to light and causing the issue your having with it.
I hope this info helps sir and that you get it figured out soon.
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