KNS Precision AR15/M16 Firing Pin Retaining Pin

Manufactured by KNS Precision
Manufactured by KNS Precision
25 Reviews

In Stock

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The KNS Precision PERMA Pin is a must-have upgrade for your AR-15 bolt carrier. This drop-in replacement is machined from tool steel for a long-lasting, reliable solution. It replaces the standard cotter pin found in the bolt carrier and is designed to retain the firing pin as in original Stoner rifles. This pin has a black finish and provides a fast and easy replacement to the often frustrating task of reassembling your BCG. It is an essential upgrade for any AR-15 owner and is sure to make maintenance and reassembly much simpler.


  • Machined from tool steel for a long-lasting and reliable solution
  • Replaces the standard cotter pin in the bolt carrier
  • Retains the firing pin as in original Stoner rifles
  • Black finish for a sleek aesthetic
  • Fast and easy drop-in replacement
  • Essential upgrade for any AR-15 owner
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BrandKNS Precision
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to

Ratings & Reviews

25 reviews


Works great


Recently got a 7.62x39 AR pistol and it would destroy the firing pin retaining pins after every trip to the range. Replaced it with the perma pin and so far It's taken the beating without fail.

Perfect fit CMMG AR15


Replaced the original bent cotter pin in a CMMG AR15. Nice fit. Moderate pressure to fully seat.

Works well


Very consistent tension, the cotter keys always seem all over the place, some are loose, some are tight, some don't line up real great. These fit right, and fit the same every time, picked up a couple more.

KNS AR15 Firing pin retaing pin


worked great



fits well, have not ran in rounds yet. as for primary arms, price was right, shipping was fast as always.

broke on install


prongs broke off on the first attempt to install in my anderson bcg.

Worth the few bucks for your firearm.

by -

My first time disassembling my AR's BCG was the first time I ever broke the stock retaining pin. This KNS is wonderful! I've taken the BCG apart dozens of times and it hasn't broken yet. About to buy some more as backups.

The good and the bad

by -

Broke on initial install. Very disappointed with this product too brittle. As always Primary Arms customer service handled this problem without hesitation. Thank you again for the awesome customer care.



Worked great in my
Colt M16


by -

This is the only KNS product that I can’t get behind. Broke 3 going in and 1 coming out. Still have some left but going back to the old cotter pin. Sometimes they take a little finessing but always work and if you have to throw one away it doesn’t cost as much.