View Full Version : KNS pins
I did do a search and did read for about an hour on the subject. Seems like all i got out of it was people so polarized about the subject, it was hard to get to the facts.
First off let me say, i'm not looking to spend money just for fun. If i were i would buy more ammo or get more training. I've done both. But i've been a maintenance professional for 40years. That is what leads me to bring up this question. And the second reason is i just received my colt 6933 and dont need any problems with the lower. The 3rd reason is i am still trying to learn all i can learn about all things i deal with. I hope i never quit learning. The main rifle i use is a LMT lower that has had the stock trigger tuned by a professional gun smith, the magpul enhanced trigger guard installed, and a magpul stock put on. The upper is a BCM 16" with a battle comp, magpul hand guards, mid length, and a aimpoint C3. This is all i need. So my point here is i'm not a gadgett sort of person. My concern is the rotating pin on the hammer. Metal to metal is a wear point if there is movement. The softer of the two will wear. Is this a problem. I just dont want a problem with my 6933 lower. I want to believe its not a problem, because if it were, i think i would be seeing the issue in question being addressed by the manufacturers of the lower. I am looking for some good input and mileage of others. thanks
Are you asking if they are worth it or a worthy upgrade?
I run KNS pins on my SBR. It is my first and only build that utilizes them and so far I cannot tell a difference. My wife bought them for me as a gift, so I decided to use them.
All of my other builds have used Mega and Sun Devil lowers with DD LPKs and I haven't had a single FCG problem yet. If or when I have problems with any of guns, I'll look into the KNS pins...but until then I'll just save the money and spend it elsewhere.
Thanks
All you're going to get here is the same polarity of opinions. Generally, those that are opposed are VERY opposed...will likely inhibit those that think they're a good idea from taking a stand here.
The way I see it, if rotating hammer pins were a big deal, some kind of anti-rotation mechanism would likely be part of the TDP. It's not like the AR15 platform, including the hammer pins, hasn't had a lot of field testing over the last 40 years.
Rotating pins aren't going to cause a problem on your new lower. The main advantage of the KNS pins is with 9mm or F/A weapons. I have KNS pins on my lower and I plan to use them on all future builds, they give me peace of mind :p
Magic_Salad0892
11-27-10, 21:41
They make the trigger pull a little nicer, IMO.
No real difference though.
They don't hurt anything and they *might* help with trigger pull and they're stronger, so there's no downsides and a few possible upsides.
I have them in both of my SBR's, but they aren't a must have item.
I mainly use them because I occasionally turn my SBR's into 9mm and have broken standard hammer pins, but have never broken a KNS.
The_War_Wagon
11-27-10, 22:23
I run them on my 14.5" Addax custom build and my POF-415, because both tend to recoil a bit harder than my other 2 complete rifles (BCM middy and an M&P15T). I figured the extra protection - to make sure the pins don't walk away on me - couldn't hurt. For $30 + or -, it's good insurance.
I did do a search and did read for about an hour on the subject. Seems like all i got out of it was people so polarized about the subject, it was hard to get to the facts.
The facts are simple. The AR firearm is an engineered system. There is a engineering reason it was not designed with anti-rotation pins, and an engineering reason why, after 40+ years, .gov has not requested the TDP be changed to add them. Once you understand how FCG works, you will see why it is this way.
The TDP doesn't specify a lot of things people do to their carbines.
Does the TDP have anything to say about mid-length gas systems on a 14.5" barrel?
Does the TDP say anything about Failzero coated BCG's?
Geissele triggers?
I have broken standard hammer pins in a 9mm SBR (even with a "Q" buffer, 9mm hammer and +15% buffer spring). I've never broken a KNS pin. That right there is enough for me to put them in my carbine.
The anti-rotation stuff doesn't matter to me one way or another.
ThirdWatcher
11-28-10, 00:24
The main advantage of the KNS pins is with 9mm or F/A weapons.
Why 9mm weapons? (Just curious, as I have a Colt 6450.) :)
Unless your gun has a happy switch than you are simply decorating your lower with these rather useless pins.
Many people will at least admit they put them on their lowers because they look good. The ones who don't admit it simply do not understand how the AR fcg works.
When I see them on people's gun's I say to myself, " why do they have accu wedges over their trigger pin holes:sarcastic:
eta...please explain how these widgets make the trigger pull nicer???
Magic_Salad0892
11-28-10, 01:57
Unless your gun has a happy switch than you are simply decorating your lower with these rather useless pins.
Many people will at least admit they put them on their lowers because they look good. The ones who don't admit it simply do not understand how the AR fcg works.
When I see them on people's gun's I say to myself, " why do they have accu wedges over their trigger pin holes:sarcastic:
eta...please explain how these widgets make the trigger pull nicer???
On my old LWRCi lower, the trigger pull had a more solid reset for some reason.
Think Glock triggers.
I know in the end i will have to make the decision. But i sure do appreciate the discussion thus far. I to have a 6450. No happy switch but that sort of caught my attention also.
Quiet-Matt
11-28-10, 07:12
LOL! I love reading these KNS pin "discussions". The fact is, if you have walking pins you have a problem. Will these pins keep the pins from walking out of your out of spec lower? Yep. So, with the walking issue put to bed lets move on. Pin hole "egging" due to pin rotation is BS in a quality lower. Period. Moving on... It's pretty much the consensus that the KNS pins are a good move on 9mm and F/A weapons to avoid pin breakage. Pin breakage is most likely due to substandard pins being supplied by manufactures and packed in that DPMS or BushMaster LPK you bought. So, it sounds like they are stronger than most of the pins that are on the market today. Now, has anyone ever heard of the KNS pins causing a malfunction? So, it stands to reason that if the pins don't cause problems, but offer the user the piece of mind that they have stronger pins, why not? In the scheme of things, after pouring your hard earned money into your AR making sure that every part is the best, most durable you can get your hands on. Why not spend the $30 to ensure that you have covered all the bases.
Now, has anyone ever heard of the KNS pins causing a malfunction?
So many failures they had to come out with a new gen2 design.
The newer pins are harder than the receiver, so when they break, instead of only having to fix a $2 pin, you now have an egged receiver. And since it is captive, you may not even know they have broken right away, making the damage worse. Imagine how much fun that is on your $10K RR. This too, is documented.
An automobile is an engineered system. There is an engineering reason automobiles are not designed with swiss cheese for engine blocks and apple sauce for oil. Who says an engineered system can't be improved upon? Even after 100+ years of the automobile, new designs come out all the time and there still isn't a car guaranteed not to break down. The AR is no different.
The facts are simple. The AR firearm is an engineered system. There is a engineering reason it was not designed with anti-rotation pins, and an engineering reason why, after 40+ years, .gov has not requested the TDP be changed to add them. Once you understand how FCG works, you will see why it is this way.
So many failures they had to come out with a new gen2 design.
No
The newer pins are harder than the receiver, so when they break, instead of only having to fix a $2 pin, you now have an egged receiver. And since it is captive, you may not even know they have broken right away, making the damage worse. Imagine how much fun that is on your $10K RR. This too, is documented.
If this is indeed documented, please provide a link.
An automobile is an engineered system. There is an engineering reason automobiles are not designed with swiss cheese for engine blocks and apple sauce for oil. Who says an engineered system can't be improved upon? Even after 100+ years of the automobile, new designs come out all the time and there still isn't a car guaranteed not to break down. The AR is no different.
Nobody says it cannot be improved. A replacement part that fails more than the original is not an improvement.
No
They publicly admit it:
Some of the pins in the earlier models (mine included) were breaking at the oil hole. This occured because the oil holes were drilled thru the threaded section of the pin which weakened the pin there. KNS moved the oil holes a little further inboard and out of the threaded area. No problems with mine so far.
John C in PA
John, You are correct about the oil holes in the trigger pins. We also made the Hammer pin solid on all of the Gen 2 series pin sets. They are over 40% stronger than the Gen 1 pins. The Gen 1 pins are already stronger than the stock pins.
We had 14 breakages. 13 in 9mm 1 in .223 suppressed. (http://www.uzitalk.com/forums/archive/index.php/t-51522.html)
If this is indeed documented, please provide a link.
See above. Dozens of other links and documented cases, if you care to learn how to google.
KNS is silly nonsense junk. Just look at the rest of KNS's product line and you'll see what a goofball operation they are.
Rotating pins aren't going to cause a problem on your new lower. The main advantage of the KNS pins is with 9mm or F/A weapons. ...:p
Their real advantage is the 9mm F/A. It violently cocks the hammer in the first 1/4 inch (I believe that is the correct number) of the bolt's travel. This violent action can be reduced slightly by ramping the bolt. The KNS pins are stronger than the factory pins and therefore help prevent pin breakage and receiver damage during this violent action.
I have a friend who was recently hired by the Diplomatic Security Service and attended their training on the 9mm M-16. He said the instructors kept spare hammer pins in their pockets as they broke several a day on the range.
So many failures they had to come out with a new gen2 design.
The newer pins are harder than the receiver, so when they break, instead of only having to fix a $2 pin, you now have an egged receiver. And since it is captive, you may not even know they have broken right away, making the damage worse. Imagine how much fun that is on your $10K RR. This too, is documented.
Gen 1 is stronger than the factory pins. Even so, the Gen 1 pins still broke on occasion. KNS tried to fix this by redesigning their hammer pin. They made the new Gen 2 pin a solid pin instead of the Gen 1 hollow pin. Because it is a solid pin they also had to change the way it is held in place.
As to the pins being harder than the receiver and egging out the hammer pin holes on a "$10,000.00" RR, the hammer holes on my "$10,000.00" RR were egged out by a factory pin that broke while running my 9mm upper FA. I wish I had installed KNS pins sooner as they may have prevented this.
Just for the record, My lowers are either LMT, Colt, or Sabre Defense.
In my original post i stated that metal against metal rub, one metal will wear more than another. How much in this case, i dont know. It sure would be nice to hear from someone who has a lower with lots of rounds thru it that has had the same pins the entire time and do some measuring just to see if anything has changed. Pin wear or lower wear or neither. Sure would add some facts to the discussion.
I have seen M16's with egged pin holes. I will say these receivers had thousands upon thousands of rounds through them and were probably close to the end of their life expectancy. In any case, with the gov't paying a couple hundred dollars or whatever it is for an M16 lower, it may just not make sense. For a Colt M16 in the NFR owned by an individual, that makes a difference because of the value of the receiver. They can be repaired, but who wants to go through that crap if you can avoid the problem all together. With the improvements with the Gen2 stuff, it may be a worthwhile investment. You have to consider though, will you ever shoot enough to realize the benefit?
I'll bet the government gets their M16/M4 lowers for under $100
It makes sense to take preemptive measures with something as valuable as a transferable M16 lower.
I personally think the non-rotating pin is a beneficial improvement be it used on 9mm F/A or semi 5.56. The design is still evolving and I don't think it's fair to throw out the whole idea because of a few problems. I have them on my 5.56 and I admit, I like the way they look. I also like knowing that they will not ever walk out. If they break, so be it. Its only a BM lower anyway :)
I have seen M16's with egged pin holes. I will say these receivers had thousands upon thousands of rounds through them and were probably close to the end of their life expectancy. In any case, with the gov't paying a couple hundred dollars or whatever it is for an M16 lower, it may just not make sense. For a Colt M16 in the NFR owned by an individual, that makes a difference because of the value of the receiver. They can be repaired, but who wants to go through that crap if you can avoid the problem all together. With the improvements with the Gen2 stuff, it may be a worthwhile investment. You have to consider though, will you ever shoot enough to realize the benefit?
In all of my years I have yet to see "egged out" lower holes from pins. What I have seen are morons who have beat on them and pounded them in, incorrectly and other silly non sense.
I didn't mean to imply the pin holes were grossly deformed, only slightly misshapen. I also didn't meant to imply I 100% sure this was due soley to use. Could poor maintainance practices and/or ignorance be a contributing factor? Sure. I do know I have experienced pins walking a bit due to what I attributed to the out of round shape of the pin hole.
This is only slightly off the topic here, but has anyone ever removed the j-hook spring from the hammer when using KNS pins? It serves no purpose with these pins and removal would get rid of some friction. Without the groove for the spring to fit in, I would think there might be considerable tension exerted.
so let me get this straight, if I have a lower that has the hammer pin rotating as the trigger is pulled, these KNS pins are a "MUST" or not?
My dept has some hand me down guns (from the government) that are full auto and they have this rotating hammer pin issue, is this something that needs fixed or not?:confused:
It's not something that really needs "fixed" Iraqgunz knows his stuff and if he hasn't seen an "egged out" hole from rotating pins, I believe it.
It really comes down to if your dept. wants to spend $32 on each rifle. If the holes end up wearing, oversized pins are available.
so let me get this straight, if I have a lower that has the hammer pin rotating as the trigger is pulled, these KNS pins are a "MUST" or not?
My dept has some hand me down guns (from the government) that are full auto and they have this rotating hammer pin issue, is this something that needs fixed or not?:confused:
they have this rotating hammer pin issue, is this something that needs fixed or not?
No.
The only reason I'd buy the pins is if you're running a 9mm AR and want a stronger hammer pin.
I think you might also consider what trigger you are using as most custom triggers come with their own pins. It is my understanding that the custom trigger's pins are semi-proprietary in that you might be able to use the existing pins with them, but they will work work better with the supplied pins. Which means why reduce the function of say a Geissele SSA trigger by using KNS pins in it:(
Iraqigunz has seen more full auto ARs in every configuration imaginable than most of us will in a lifetime and if he has not seen an egged out pin hole, well, you be the judge
so let me get this straight, if I have a lower that has the hammer pin rotating as the trigger is pulled, these KNS pins are a "MUST" or not?
Must NOT.
Rotating pins is the engineered design.
Rotating pins is the engineered design.
Could you explain the rationale behind engineering that pin to rotate? I'm not a gunsmith, but I am a pretty good mechanic, and I can't think of any reason for that pin to move. I'm surely missing something.
You're not missing anything.
There's no rotation engineered into the design.
I'm sure a small amount of rotation was accounted for in the design, but there is zero reason for those pins to rotate.
The spring captured pins are cheap to manufacture and easy to install, end of story.
Glock uses the same design pin as their trigger pin, but it's the spring loaded slide stop lever that holds it in place.
Could you explain the rationale behind engineering that pin to rotate? I'm not a gunsmith, but I am a pretty good mechanic, and I can't think of any reason for that pin to move. I'm surely missing something.
If the pin does not move, then all of the stress and friction is put into a single point, in the center of the pin, which is its weakest point.
By allowing the pins to move, the center is not stressed as above; the friction point surface area is doubled and moved to the outside of the pins, where they are strongest.
Now in a low-rate-of-fire gun such as S/A, it might not matter much, but in a F/A gun friction is much much more severe.
ETA:
I do not mean rotate as 360 degrees round and round. I mean it rotates a little in conjunction with the hammer/trigger.
SpankMonkey
12-01-10, 07:20
I've been using KNS pins for the last four years. I also use reduced power JP springs in my guns. In nine years of shooting ARs, I have seen two guns where one of the pins backed out causing the guns to stop working. With that thought, and the reduced power springs it gives me peace of mind knowing my pins won't back out. Beyond that they are a gimmick. YMMV
I have seen M16's with egged pin holes. I will say these receivers had thousands upon thousands of rounds through them and were probably close to the end of their life expectancy.
I might add they were used hard in service and had parts replaced without doubt, so poor maintenance or parts replacement practices could always play a role. Remember, some of the few receivers I have seen that had this issue had been in inventory for decades with some having had little maintainance other than a cleaning. You are shooting a weapon and you notice the pin is walking a bit. You notice the pin hole is a bit misshapen. That is it. I mean they still shot, it was not like a catstrophic failure was neccsarily immanent. The fit of the pins was just a bit loose.
It's not something that really needs "fixed" Iraqgunz knows his stuff and if he hasn't seen an "egged out" hole from rotating pins, I believe it.
Not doubting he hasn’t experienced deformed or damaged pin holes that he could attribute to something other than someone beating the pins back in as he stated. It is unlikely in today’s world there are any decades old M16’s in inventory that have seen hard use in a combat environment as most are destroyed as unservicable, but perhaps a few slip through the cracks, and not seeing them doesn’t mean they haven’t existed.
So, to get back to the original question, are they necessary? No. Are they a bad idea? No. Do they work as advertised? Yes. Will most realize any benefit from them? Probably not. Would I run them on an NFA registered M16? Perhaps.
If the pin does not move, then all of the stress and friction is put into a single point, in the center of the pin, which is its weakest point.
By allowing the pins to move, the center is not stressed as above; the friction point surface area is doubled and moved to the outside of the pins, where they are strongest.
Now in a low-rate-of-fire gun such as S/A, it might not matter much, but in a F/A gun friction is much much more severe.
ETA:
I do not mean rotate as 360 degrees round and round. I mean it rotates a little in conjunction with the hammer/trigger.
Wow, I'd like to see the engineering paper that describes that process with math. So, you're saying that all the rotational force and friction of the hammer is concentrated on the groove in the center of the pin, unless that pin is allowed to rotate a few degrees. You inadvertantly just gave the perfect reason for the KNS design, which does away with the groove. Without that groove, the pin would be many times stronger and therefore should not have to rotate, which, of course, would obviate any chance of the holes in the receiver becoming worn because of said pin rotation. With the other advantage of not ever being able to walk out, they would seem to be a "no lose" product.
The only disadvantage I can see, is that it takes a little more time to completely strip the lower, but I can't think of any scenario where I would be in a hurry to do that anyway.
Now, I've only witnessed, firsthand, one real world problem with an AR that the KNS pins would have prevented, but for a mere $30, I'll keep using them in my guns, just in case.
We've got quite a few auto guns that are run real real hard.
We've experienced almost every kind of failure you can have, but NEVER a problem with walking pins or 'egged' holes.
Lost River
12-01-10, 16:45
In all of my years I have yet to see "egged out" lower holes from pins. What I have seen are morons who have beat on them and pounded them in, incorrectly and other silly non sense.
EXACTLY.
Mouth breathers who are not authorized to be working on their guns, don't have a clue, but think they do, are what causes lower holes to get "egged out" or "wallered out".
If it is a work gun, go see your armorer.
Same applies for installing plates with single point attachments. I cannot tell you how many guys have approached me with issued M4s with a takedown pin spring that was mashed, half sticking out and said
"it was like that when I got it" .:rolleyes:
Actually you would be wrong as myself and many others who have been overseas have seen lowers that were originally M16A1's that were restamped and in use by National Guard and Reserve units. To include Air National Guard personnel.
The most recent was around late 2006. Strangely enough the weapon was working fine and the holes had no issues.
I might add they were used hard in service and had parts replaced without doubt, so poor maintenance or parts replacement practices could always play a role. Remember, some of the few receivers I have seen that had this issue had been in inventory for decades with some having had little maintainance other than a cleaning. You are shooting a weapon and you notice the pin is walking a bit. You notice the pin hole is a bit misshapen. That is it. I mean they still shot, it was not like a catstrophic failure was neccsarily immanent. The fit of the pins was just a bit loose.
Not doubting he hasn’t experienced deformed or damaged pin holes that he could attribute to something other than someone beating the pins back in as he stated. It is unlikely in today’s world there are any decades old M16’s in inventory that have seen hard use in a combat environment as most are destroyed as unservicable, but perhaps a few slip through the cracks, and not seeing them doesn’t mean they haven’t existed.
So, to get back to the original question, are they necessary? No. Are they a bad idea? No. Do they work as advertised? Yes. Will most realize any benefit from them? Probably not. Would I run them on an NFA registered M16? Perhaps.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.