View Full Version : Different Cotter Pin
Hello all -
I was at the range the other day and a man was disassembling his ar15. I noticed that he had a different cotter pin than what I had in my colt. I've looked it up, and its a KNS Perma pin? that is claimed to be the "original".
Anyone have info on this? The gentleman also claimed that this version of the cotter pin was of a higher quality. I've only ever bent one cotter pin, and took all of two seconds to find a replacement. :confused: Why is this supposedly better?
Razorhunter
04-27-07, 21:05
Anything made of tool steel is going to be preferable to some piece of shit cotter key. It's basically the original design Eugene Stoner used....
http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=PP&reference=/cgi-bin/commerce.cgi%3Fsearch%3Daction%26keywords%3D%26searchstart%3D0%26template%3DPDGCommTemplates/FullNav/SearchResult.html%26category%3DKNSP
They're based on the very early original design.
I've got one installed on a Colt BCG.
It's a pain in the ass to pull and reinstall compared to the cotter pin.
Razorhunter
04-27-07, 22:14
The only thing I don't understand about the Perma Pin from KNS, is the instructions with mine said to install it with the SLOT in the pin, horizontal in relation to the length of the bolt.
IOW, you don't install the pin with the slot going up and down...
WHAT's the deal with that? Some sort of strength issue with the grain of the steel I presume???
Anyone have a link on info about why the change was made? Can't find anything.
Paul - I'm taking a wild guess, but maybe the pin won't take a set at the flared end. If it were installed horizontally then the pressure would be distributed and long term it would stay tight?
The KNS Perma Pin is much stronger than standard cotter pins. I see bent cotter's all the time so it is a frequent occurence I think.
C4
I run the KNS perma pin in my carbine. It's easier to install and remove for me and I've never had any problems. I used to get bent cotter pins quite often but the KNS fixed that.
Robb Jensen
04-28-07, 21:31
I've seen no need for the KNS perma pin. When using a shrouded carrier I never seen a bent FPRP. An old USMC 2112 showed me a trick many moons ago. The trick is when reinstalling the FPRP is to make it 90 degrees different than the firing pin. This allows the firing pin to apply force to both legs of the FPRP. Using this method I've never worn FPRP nor broken a FPRP using a shrouded carrier.
I've seen no need for the KNS perma pin. When using a shrouded carrier I never seen a bent FPRP. An old USMC 2112 showed me a trick many moons ago. The trick is when reinstalling the FPRP is to make it 90 degrees different than the firing pin. This allows the firing pin to apply force to both legs of the FPRP. Using this method I've never worn nor broken a FPRP using a shrouded carrier.
I personally have never had a bent CP, but do see them a lot. I am guessing that there are a lot of low quality CP's out there and also a lot of unshrouded carriers.
C4
I personally have never had a bent CP, but do see them a lot. I am guessing that there are a lot of low quality CP's out there and also a lot of unshrouded carriers.
C4
What is meant by the term "unshrouded carrier"?
Robb Jensen
04-29-07, 18:53
What is meant by the term "unshrouded carrier"?
The carrier on the left is unshrouded, the middle and right carrier are shrouded.
http://img.photobucket.com/albums/v408/gotm4/carriers.jpg
Are shrouded carriers found only in select fire guns? Can one use a shrouded carrier in a semi AR to "protect" all associated parts i.e. the cotter pin etc within the carrier?
Robb Jensen
04-29-07, 21:56
Are shrouded carriers found only in select fire guns? Can one use a shrouded carrier in a semi AR to "protect" all associated parts i.e. the cotter pin etc within the carrier?
Many earlier than 2004 AR15 carriers are unshrouded.
Don't intend to hijack this thread but should I be concerned with the unshrouded carriers being in a majority of my rifles? I have never had any reliability issues with any of them...
Robb Jensen
04-30-07, 04:26
Don't intend to hijack this thread but should I be concerned with the unshrouded carriers being in a majority of my rifles? I have never had any reliability issues with any of them...
Most don't have any issues except for the occasional bent FPRP.
The unshrouded carrier was a Colt idea (IMO not a brilliant one) for AR15 use only. If yours is running fine you don't have anything to worry about.
In the event of hammer follow with an AR15 notched hammer an unshrouded carrier is supposed to keep the rifle from slam firing. It does and it causes a bent firing pin as the hammer jams on the end of the firing pin.
The unshrouded carrier can only use an AR15 firing pin where as the shrouded model can use an AR15 or M16 firing pin.
Full auto carriers are all shrouded.
Ok so what size is the FPRP if i need to get one local say hardware or TSC in the event of, oops iam out of them and need them now.
I've seen no need for the KNS perma pin. When using a shrouded carrier I never seen a bent FPRP. An old USMC 2112 showed me a trick many moons ago. The trick is when reinstalling the FPRP is to make it 90 degrees different than the firing pin. This allows the firing pin to apply force to both legs of the FPRP. Using this method I've never worn FPRP nor broken a FPRP using a shrouded carrier.
Thanks for posting that pic GotM4! I checked mine right away. I have another request though: are you able to post a pic of what you mean by making it 90 degrees different than the firing pin? Do you mean that the two legs are vertical in the hole or horizontal in the hole? Much appreciated:o .
-Chris
Robb Jensen
04-30-07, 20:50
Ok so what size is the FPRP if i need to get one local say hardware or TSC in the event of, oops iam out of them and need them now.
The hardware store cotter pins will not work for long in an AR15.
I have another request though: are you able to post a pic of what you mean by making it 90 degrees different than the firing pin? Do you mean that the two legs are vertical in the hole or horizontal in the hole?
With the carrier laying horizontal the FPRP should be inserted vertically, one leg will be sitting on top of the other. So that the firing pin will make contact with both legs of the FPRP not just one.
The hardware store cotter pins will not work for long in an AR15.
Yes i understand that, its a just in case plan i usually carry spare kits anyhow or a second gun
Copy that. Thanks for your patience GotM4;)
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.