AR 15 buffer damage... anybody seen this before?

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valmet762

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I have a collapsible stock on my ar, and i have some serious dings on my buffer.. the marks are from the buffer retainer post.. i rotated the buffer around and get fresh marks every time.. anybody have any suggestions?

here's the pics

DSC04426.jpg



DSC04419-1.jpg
 
Are you using a standard bolt?

I just checked my guns, and when the bolts are fully forward and locked they seem to hold the buffer back from that post.

It's almost like DLASK drilled that detent hole too far forward.
 
the upper is a colt hbar.. bolt is also colt, original with upper.. when the bolt is locked forward, i see daylight between the upper and lower toward the back.. looks like the bolt is not making contact with the buffer when its locked. i've put a couple of hundred rounds thru this lower with my colt upper.
 
will just keep getting worse, i believe the bolt is supposed to rest against the buffer... that detent looks to be holding the buffer a tad to far back into the stock.
 
You said the bolt is a Colt. What about the carrier, what make is it? Could it be an out of spec carrier, or one that's been shaven at the rear and is now too short to not hold the buffer away from the retainer pin?

What are all the blue marks from on the buffer face? ... and what are those two zip tie looking rings next to the castle nut?
 
easy said:
You said the bolt is a Colt. What about the carrier, what make is it? Could it be an out of spec carrier, or one that's been shaven at the rear and is now too short to not hold the buffer away from the retainer pin?

What are all the blue marks from on the buffer face? ... and what are those two zip tie looking rings next to the castle nut?
Click to expand...

the bolt and carrier are both colt.. as is the entire upper..

the blue marks are ink that i put on it to see if i could see the contact points of the bolt ( i later wiped most of it off)...

the black cable ties hold a ring where i attach my "poor man's" single point sling.
 
The lower specs for the distance from the back face of the receiver to the middle of that post hole is 0.565 +/- 0.002 ... I measured 2 of my unbuilt ones and they conform. Maybe you can check yours?
 
To the OP:
I hate to be a wet blanket, but first you had problems with the bolt latch, and now the buffer retainer hole is too far back........I'm kind of thinking that lower is out of spec. :(

Just looking at the picture, it looks like that retainer is too far in from the end of the rear lug recess.
It's hard to judge the scale, but it also KINDA looks like the pin is a larger diameter at the top.....but that could just be an optical illusion.
Your buffer should protrude a little so that when the upper closes, the rear of the carrier pushes the buffer back away from that pin.
 
glock9x19 said:
The lower specs for the distance from the back face of the receiver to the middle of that post hole is 0.565 +/- 0.002 ... I measured 2 of my unbuilt ones and they conform. Maybe you can check yours?
Click to expand...


measured it... same a yours, .565 exactly.

my upper is a large hole pivot pin.. i had to use an adapter to fit the small hole lower.. i'm wondering if the adapter (being eccentric in shape) may be keeping the upper too far apart from the back of the lower, causing the buffer to not reach the carrier when locked?
 
valmet762 said:
the upper is a colt hbar.. bolt is also colt, original with upper.. when the bolt is locked forward, i see daylight between the upper and lower toward the back.. looks like the bolt is not making contact with the buffer when its locked. i've put a couple of hundred rounds thru this lower with my colt upper.
Click to expand...

Originally Posted by valmet762 possible... but i'm thinking it may have something to do more with using a large hole upper and small hole lower.
Click to expand...

Originally Posted by valmet762

my upper is a large hole pivot pin.. i had to use an adapter to fit the small hole lower.. i'm wondering if the adapter (being eccentric in shape) may be keeping the upper too far apart from the back of the lower, causing the buffer to not reach the carrier when locked?
Click to expand...

I think you are basically addressing the problem being with the large pin to small pin adapter.

Being eccentric, can that adapter be rotated or reversed to mate the lower and upper properly? Can you show us a picture of the adapter?
 
Last edited:
valmet762 said:
my upper is a large hole pivot pin.. i had to use an adapter to fit the small hole lower.. i'm wondering if the adapter (being eccentric in shape) may be keeping the upper too far apart from the back of the lower, causing the buffer to not reach the carrier when locked?
Click to expand...

So parts that were never intended to be used together are not working well.

For the sake of a proper $200 upper you are beating your rifle to death.
 
It is bashed up because because the bolt carrier is not resting on the buffer.

Instead, the buffer is smashing into the buffer retaining pin.

Reason - the upper is out of spec. Mostly likely, the barrel extension is too long and the barrel sits too far, when the breech is closed the BGC is too far forwards.

Look at your upper in the picture - the bolt carrier is flush with the upper at the open end. That is not right.
 
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