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LutzNutz
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Posted: 6/16/2012 12:12:53 AM
Hi guys,

I finished my first build this week, using a PSA lower and LPK, a PSA 20" assembled upper, and a BCM BCG. I took it to the range today to zero the sights in, and ran into an issue. I was using Tapco mags and Aguila ammo, and the rifle would jam when feeding on the right ramp about every 8 to 10 rounds. The bullet wouldn't ride up the ramp, it would stick on the ramp and the BCG would push the bullet back into the case about 1/2 inch. I didn't have any other ammo or mag brands to test, so I'm not sure where the problem is. It feeds fine on the left ramp.

Has anyone experienced this? Being a AR15 newb, I'm not sure where to begin to diagnose this problem. Thanks!
GADeerHunter
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Posted: 6/16/2012 12:23:33 AM
[Last Edit: 6/16/2012 12:24:13 AM by GADeerHunter]
Originally Posted By LutzNutz:
Hi guys,

I finished my first build this week, using a PSA lower and LPK, a PSA 20" assembled upper, and a BCM BCG. I took it to the range today to zero the sights in, and ran into an issue. I was using Tapco mags and Aguila ammo, and the rifle would jam when feeding on the right ramp about every 8 to 10 rounds. The bullet wouldn't ride up the ramp, it would stick on the ramp and the BCG would push the bullet back into the case about 1/2 inch. I didn't have any other ammo or mag brands to test, so I'm not sure where the problem is. It feeds fine on the left ramp.

Has anyone experienced this? Being a AR15 newb, I'm not sure where to begin to diagnose this problem. Thanks!


Can you get a pic of the feed ramps?

My first impression would be a mag problem.. considering they are Tapco... How many different mags did you try?
CLICKBANGBANG
Buried Susie Derkins under the tire swing.
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Posted: 6/16/2012 12:44:25 AM
First off... Welcome!

Sounds like a bad mag. How many do you have to try? Stick with Pmags or quality USGIs.
Trapped by a hideous graknil, Spiff draws his trusty atomic napalm neutralizer. "Chew electric death, snarling cur!"
chewbacca
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Posted: 6/16/2012 12:47:08 AM
I would be willing to bet its a bad mag(s). Use USGI, Pmags, or Lancer.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety."
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LutzNutz
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Posted: 6/16/2012 1:05:43 AM
[Last Edit: 6/16/2012 1:10:23 AM by LutzNutz]
Here's a shot of the ramps. If you look, you can see that the feeds aren't symmetrical.

I only tried Tapcos since that was all I had with me. It happened with both of my Tapco mags.

I figured it was the mags, since the loading issues I've had with other firearms usually boil down to mag issues. I didn't want to order a bunch of mags without a second or third opinion though.

http://img94.imageshack.us/img94/711/rampss.jpg

and the jammed cartridges:

http://img820.imageshack.us/img820/6118/cartss.jpg
CLICKBANGBANG
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Posted: 6/16/2012 1:26:37 AM
[Last Edit: 6/16/2012 1:30:21 AM by CLICKBANGBANG]
Originally Posted By LutzNutz:
Here's a shot of the ramps. If you look, you can see that the feeds aren't symmetrical.

I only tried Tapcos since that was all I had with me. It happened with both of my Tapco mags.

I figured it was the mags, since the loading issues I've had with other firearms usually boil down to mag issues. I didn't want to order a bunch of mags without a second or third opinion though.

http://img94.imageshack.us/img94/711/rampss.jpg

and the jammed cartridges:

http://img820.imageshack.us/img820/6118/cartss.jpg


It's not the mags... That upper needs to go back to PSA. The extension ramps are not lining up with the upper properly. The bullet is jamming in the little hole between the upper and extension and getting stuck. It should be a smooth transition between the bottom of the ramp on the upper and the top of the ramp on the barrel extension. Email PSA about it. Send them the pics.
Trapped by a hideous graknil, Spiff draws his trusty atomic napalm neutralizer. "Chew electric death, snarling cur!"
GADeerHunter
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Posted: 6/16/2012 1:35:10 AM
Originally Posted By CLICKBANGBANG:
Originally Posted By LutzNutz:
Here's a shot of the ramps. If you look, you can see that the feeds aren't symmetrical.

I only tried Tapcos since that was all I had with me. It happened with both of my Tapco mags.

I figured it was the mags, since the loading issues I've had with other firearms usually boil down to mag issues. I didn't want to order a bunch of mags without a second or third opinion though.

http://img94.imageshack.us/img94/711/rampss.jpg

and the jammed cartridges:

http://img820.imageshack.us/img820/6118/cartss.jpg


It's not the mags... That upper needs to go back to PSA. The extension ramps are not lining up with the upper properly. The bullet is jamming in the little hole between the upper and extension and getting stuck. It should be a smooth transition between the bottom of the ramp on the upper and the top of the ramp on the barrel extension. Email PSA about it. Send them the pics.


Are you talking about the right, or the left feedramp? Yes, they aren't aligned right, but to me the LEFT feedramp looks worse that the right one, yet its the right one thats causing problems.

At any rate, contact PSA.

Unicorn
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Posted: 6/16/2012 1:36:38 AM
Probably a bit of both. The barrel extension isn't lining up with the receiver. Could just be that the barrel rotated a little when it was installed in the receiver, or that the index pin is off center.
xtreme762
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Posted: 6/16/2012 8:37:05 AM
That's some pretty shotty quality control right there. You can see where the rounds are hanging up. Look at the left side of the right ramp. Clear as day the rounds are getting jammed up on the edge of the barrel extension ramp.

I'll bet the headspace is way out on the rifle as well. I wouldn't shoot even one more round out of that thing, and I would demand it be fixed or replaced. Think about it this way; you have an explosion that produces close to 60,000PSI going off 3 inches from your face. Is it worth it?

Send it back and get it fixed or replaced, and never buy from that manufacturer again.
"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke
JeffCsr
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Posted: 6/16/2012 9:33:39 AM
Originally Posted By xtreme762:
That's some pretty shotty quality control right there. You can see where the rounds are hanging up. Look at the left side of the right ramp. Clear as day the rounds are getting jammed up on the edge of the barrel extension ramp.

I'll bet the headspace is way out on the rifle as well. I wouldn't shoot even one more round out of that thing, and I would demand it be fixed or replaced. Think about it this way; you have an explosion that produces close to 60,000PSI going off 3 inches from your face. Is it worth it?

Send it back and get it fixed or replaced, and never buy from that manufacturer again.


It's just a clocked barrel, needs to be re indexed. Simple adjustment but I agree, very dangerous in your case. Any of those rounds could've blown your upper to pieces if you got them to feed.
LutzNutz
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Posted: 6/16/2012 11:24:30 AM
I think from the way it's clocked, the left ramp still feeds fine, but the right clips the feed ramp.

PSA is closed today, but I'll give them a call Monday. I looked everything over when I received the upper, but there was so much grease on the ramps I guess I missed the misalignment.
Direct-Drive
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Posted: 6/16/2012 11:25:32 AM
Probably a little of both.
Possibly more on the mag.

Your "on deck" cartridge should look similar to this......



Pmags and USGI mags are cheap.
Why monkey with Tapco ?
IceDiver
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Posted: 6/16/2012 11:35:45 AM
[Last Edit: 6/16/2012 11:38:08 AM by IceDiver]
When your bolt is stripping the rounds for the right side, they are dipping enough for them to catch on the lip that
is there due to your barrel extension not matching you upped feed ramps. 10 seconds with a file would fix it if you
decided to do so.

I highly doubt your headspace is off from that minor of a clocking issue.

You could probably shim on your index pin to make the extension and upper receiver cuts line up better too.

edited to add -

Different mags might fix the problem for now, but the potential for it to re-occur would still be there.
Fix it yourself or send it back.

CLICKBANGBANG
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Posted: 6/16/2012 11:43:43 AM
Originally Posted By GADeerHunter:
Originally Posted By CLICKBANGBANG:
Originally Posted By LutzNutz:
Here's a shot of the ramps. If you look, you can see that the feeds aren't symmetrical.

I only tried Tapcos since that was all I had with me. It happened with both of my Tapco mags.

I figured it was the mags, since the loading issues I've had with other firearms usually boil down to mag issues. I didn't want to order a bunch of mags without a second or third opinion though.

http://img94.imageshack.us/img94/711/rampss.jpg

and the jammed cartridges:

http://img820.imageshack.us/img820/6118/cartss.jpg


It's not the mags... That upper needs to go back to PSA. The extension ramps are not lining up with the upper properly. The bullet is jamming in the little hole between the upper and extension and getting stuck. It should be a smooth transition between the bottom of the ramp on the upper and the top of the ramp on the barrel extension. Email PSA about it. Send them the pics.


Are you talking about the right, or the left feedramp? Yes, they aren't aligned right, but to me the LEFT feedramp looks worse that the right one, yet its the right one thats causing problems.

At any rate, contact PSA.



Yes the left looks worse. But look at the copper markings on the inside of the left ramp on the barrel extension. If it hooks between the extension and receiver, it's a no go. Also if the extension is so far out that the bullet misses the ramp and hits the flat, It's a no go. Extension is out of alinement. Extension is not fitting with the upper receiver.

Trapped by a hideous graknil, Spiff draws his trusty atomic napalm neutralizer. "Chew electric death, snarling cur!"
AR18
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Posted: 6/16/2012 11:56:00 AM
Lz, where did you get the barrel from? It could be that you got a rifle extenison on a M4 upper.
chewbacca
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Posted: 6/16/2012 12:02:26 PM
Originally Posted By LutzNutz:
Here's a shot of the ramps. If you look, you can see that the feeds aren't symmetrical.

I only tried Tapcos since that was all I had with me. It happened with both of my Tapco mags.

I figured it was the mags, since the loading issues I've had with other firearms usually boil down to mag issues. I didn't want to order a bunch of mags without a second or third opinion though.

http://img94.imageshack.us/img94/711/rampss.jpg

and the jammed cartridges:

http://img820.imageshack.us/img820/6118/cartss.jpg


Wow, that looks like crap. Call PSA, the ramps are not lined up correctly. I can see the brass marks on the right side.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety."
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Gone_Shootin
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Posted: 6/16/2012 12:08:50 PM
Originally Posted By Unicorn:
Probably a bit of both. The barrel extension isn't lining up with the receiver. Could just be that the barrel rotated a little when it was installed in the receiver, or that the index pin is off center.


This is what I see too. You can see where the bullets are riding up.

I have the same problem with one of my ARs, but that's because the upper is a large pin SP2 with an offset bushing arpund the front pin. And because of that, the rounds WILL hit the edge of the barrel extension if you dont wedge the mag forward. I need to fix that......
woodsman556
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Posted: 6/16/2012 1:56:52 PM
The 5th round from the right reminds me of one of the pieces of brass from the Colt kaboom thread that everyone said was run over by a lawnmower.
feelthepayne
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Posted: 6/16/2012 2:01:48 PM
Doesn't look like your barrel extension is lining up with your feed ramps. I'm no expert, but if you've had the same problem with multiple magazines, I'd start there.
woodsman556
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Posted: 6/16/2012 2:02:53 PM
I'm wondering what the crimp is like on that ammo to push all the bullets back like that. Maybe with a bad enough feeding problem a good crimp wouldn't matter? I don't have enough experience with this stuff to know. Maybe someone that does could chime in.
Direct-Drive
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Posted: 6/16/2012 3:31:23 PM
Originally Posted By woodsman556:
I'm wondering what the crimp is like on that ammo to push all the bullets back like that. Maybe with a bad enough feeding problem a good crimp wouldn't matter? I don't have enough experience with this stuff to know. Maybe someone that does could chime in.

I thought about lack of crimp when I saw the photos.
Aguila ammo ?

1) I think his Tapco mag is presenting the on deck cartridge at a less than favorable angle.
2) Weak crimp or more likely, no crimp.
3) Barrel extension could have been indexed a little better.

LutzNutz
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Posted: 6/16/2012 3:56:08 PM
[Last Edit: 6/16/2012 4:00:24 PM by LutzNutz]
Originally Posted By AR18:
Lz, where did you get the barrel from? It could be that you got a rifle extenison on a M4 upper.


It's a PSA upper and barrel: http://palmettostatearmory.com/index.php/ar-15-05/complete-uppers/20-madness-20-cmv-chrome-lined-stripped-upper-without-bcg-or-charging-handle.html
LutzNutz
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Posted: 6/16/2012 3:58:20 PM
Originally Posted By IceDiver:
When your bolt is stripping the rounds for the right side, they are dipping enough for them to catch on the lip that
is there due to your barrel extension not matching you upped feed ramps. 10 seconds with a file would fix it if you
decided to do so.


I thought about getting the round file out this morning, but could I screw anything up by filing the ramps wider then they are supposed to be?
woodsman556
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Posted: 6/16/2012 4:01:21 PM
I would not take a file to that thing. If there is a problem with the feed ramps I'd send it back.
Direct-Drive
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Posted: 6/16/2012 4:35:36 PM
Originally Posted By LutzNutz:
Originally Posted By IceDiver:
When your bolt is stripping the rounds for the right side, they are dipping enough for them to catch on the lip that
is there due to your barrel extension not matching you upped feed ramps. 10 seconds with a file would fix it if you
decided to do so.


I thought about getting the round file out this morning, but could I screw anything up by filing the ramps wider then they are supposed to be?



If you want to send it back, don't monkey with it.
slowfatguy
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Posted: 6/16/2012 4:44:25 PM
Originally Posted By woodsman556:
The 5th round from the right reminds me of one of the pieces of brass from the Colt kaboom thread that everyone said was run over by a lawnmower.


I had the same thought.

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