Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
4/29/2012 7:37:24 AM EDT
My AR15 A2 20" barrel was removed, 0.750 FSB removed, turned down to 0.625 with 0.625 FSB installed.  Prior to changes no problem.  After new FSB, I notice some short stroking.  About 2 out of 20.  Since things were fine before with a polymer clip, I assume that the bolt (key, bolts, rings) are all OK.  The short stroke was observed while using a 2009 metal clip picked up at a trade show.  There were also two failures to feed which I attributed to the clip.  One of my diagnoses of the short stroke will be to take two properly functioning polymer clips to the range as well.  The only other thing I can think of is to check the alignment of the FSB hole.  Anything else to check?
Thanks
4/29/2012 9:00:21 AM EDT
[#1]
You have it right.
Use only known-good magazines.

#1 suspect is the new FSB and related elements.
Sounds like it's not flowing gas as freely as it was.
.

Is the FSB located properly ?
Has the barrel's gas port been constricted from the machining ?
Is the gas passageway in the new FSB constricted ?
Is the gas tube interfacing with the FSB correctly ?
Is the gas tube clear ?

.
4/29/2012 10:01:57 AM EDT
[#2]
Very high probability that the new gas block is not correctly aligned with the gas port.  Or there's been some kind of error like installing the gas tube upside down.
4/30/2012 11:36:26 AM EDT
[#3]
magazine not clip and if it works with other mags fine then there's your issue but may be misaligned fsb, gas port blockage...
AR Sponsor