PMAGS and piston SBR ?

oregonradman

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Minuteman
Feb 15, 2011
15
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Oregon
While shooting 2 different 10.5in piston uppers (HK and LWRC), using Winchester, Black Hills and Hornady TAP, the BCG would only stay open after the last shot 10% of the time. All of the 15 PMAGS were brand new with the window. There were no feeding problems with any of these mags. The buffers and springs that were used were the ones provided by HK and LWRC. The issue occured suppressed and non-suppressed. Has anyone else had this problem?
 
Re: PMAGS and piston SBR ?

Not a piston AR but I run these in my Scar 10" and my MK18 and after adding a relief cut for the BHO to properly engage and not damage the bolt (BHO wasn't sitting flush with the lower due to PMAG dimensions) they have been flawless. I also had the same issue with BETA mags, had to cut a small notch in the feed tower.