I've read many of the KNS pins discussions on ARFCOM over the years and determined that I can't drink the koolaid. However, I was digging around for a thread wherein both Steve from ADCO and Mr. Geissele both commented on the subject (I apologize for getting excessively bored at my midnight shift job). In one thread that I was reading, someone said that the KNS pins have some valid use in blowback/pistol caliber ARs. Is there a general concensus on this? Is my 9mm build the one place where these controversial pins might be needed? I have to say that I have noticed that several pistol caliber ARs I've seen posted lately have had the KNS pins installed. So, with my build, is this something that I need to consider?

Not necessarily KNS pins, but hardened pins.

OEM Colt 9mm pins are stainless steel.

Ramping the bolt also reduces peak impact force on the pins.

I see. So, the pins that come with, for instance, the Daniel Defense LPK would NOT be hardened?

I'm not a KNS pins koolaid drinker but after reading so much about how they really are a good thing for full auto and 9mm builds...I slapped a set on my 9mm build just to be safe.

Nor any other LPK; mild steel is good enough for a gas operated weapon.

9mm (and 22LR for that matter) is a lot harder on the FCG.

After a few breakages of GI pins, I use them on all my rifles. For such a cheap price, why WOULDN'T I?

For a $30 safety I use them.  I have them on all my 22 builds and SBR's.  It is cheap insurance.  I doubt I will ever shoot enough to mess the holes up but better safe then sorry.  I have wasted $30 on stupider stuff...

MAHA

I'm a rebel... I use them on all my builds. (except the ssa-e lower)

I've never done any research on them, but if some random guy on the internet says they will protect my DDLES SBR, then damnit, I'm going to listen!




Just ordered the Spikes version.

I bought a used DDLES Colt lower that had broken hammer *and* broken trigger pins in it. I put KNS pins in it and it's been fine the entire time I've owned it.

Ramped bolt
Standard hammer
Standard quality set of pins, no need for the KNS bullcrap.


If you run a NONramped bolt and a notched hammer.....for whatever damn reason, get a set of KNS pins

I probably needed them as much as the bayonet lug but I got them for the "cool" factor.

edit to add I didn't notice the rimfire, pistol catagory.  

To each his own!

Haters gonna hate!

My rifle, I do as I please!

Quit tellin me what to do bro!

My money, my rulz yo!

Cheap insurance for me.

Yep, I use them in both our lowers we run .22 rimfire dedicated uppers on. Had a pin break early on and nary a problem with the KNS ones installed ever..We shoot alot.

Ok. I am planning on buying ADCO's ramped bolt, but I think I might use them on this build as insurance. I didn't realize that the blowback of the pistol calibers created so much more wear and tear on the FCG. Thanks for the info.

I'd think a solid, e/c clipped hammer pin would work just as well, if you don't want the "switch" look on your firearm.  But then you may get scratches, wear on the outer receiever from the clips.  I use the KNS pins on receivers that I use with a .22 conversion ever since I had a broken hammer pin a number of years ago, even though the .22 bolt sub-assembly is ramped (i.e., the rear edge of the plate is cut at an angle where it interfaces to the hammer).

Best of luck with whatever you decide to pursue.

I've been shooting M16s and or AR15s since 1992 and I have never witnessed a broken pin.  What is your magic formula that you have had a few?

I can't speak for SB, but many .22 conversion users will install a weaker hammer spring to get more reliable operation, especially with lower power .22 ammo.  I theorize that the combination of the weak hammer spring counter force and the snappy recoil of the .22 is not a friend to hammer pins.

After a measely 11,000 rounds through my 9mm RDIAS SBR, the damn hammer pin broke! Cheap-ass crap mild steel!
I'm going to buy hardened pins from now on!

All kidding aside, for blow-back AR's, having more robust parts is a plus. For most other's not so much. Your money, you spend it how
you want to.

Why would you want a weaker hammer spring for striking rimfire ammo? Seems light strikes are one of the typical causes of malfunctions with .22lr.

Rimfire ammo is not as powerful as centerfire so you want less spring pressure on the hammer so it isn't as hard to reset.  It has nothing to do with reducing the primer strike, which actually does require less force.  Unreliable rimfire ignition is not usually caused by low hammer strike force, it is caused by the primer not being evenly distributed in the rim.  If you have too high a force striking the rim, you can pierce it.  Or at least weaken it too much, and the pressure blows it open.

H53, those are very valid points, but not the entire story. At one time a heavy strike was the method of
choice, but as ammo makers advance primer/powder, sealing methods, lubricants, coatings, case prep
and packaging, the forces required will go down. Having said that, there are still factors that reduce
primer/powder sensitivity and gun manufacturers take this into account.

Ah yes, if only we lived in an ideal world. But we don't and that sad fact extends to the .22lr cartridge.
In an ideal situation one would need no greater force for reliable ignition in an AR22 than Geissele's excellent
hammer spring. But taking into account - as S&W, Savage, and many others, do - the incredible ability for
moisture to seep past the loose heal crimped bullet and reduce the ignition characteristics of both powder
and primer, a bit more force on the firing pin is a common rimfire design feature. But as you state, not too much force.

Moisture is the single most detrimental factor that causes reduced primer/powder sensitivity in .22lr ammo.
That moisture starts seeping in if the ammo isn't stored in a cool, dry place, which hardly anyone, including LGS's,
do. The ammo sits on a shelf with no more concern for storage other than the room's daily environment.

Modern smokeless powder, such as Hodgedon's Li'l Gun, will last 50 or more years if properly cared for. This powder
has a stabilizer added to it to extend shelf life. Yet, as good as it is, once it is loaded in the cartridge, it now is vulnerable to moisture
which greatly (by as much as 50%) reduces primer sensitivity. Also reducing primer/powder sensitivity are the normal airborne
pollutants found in the air of every home. Annealed cartridge brass is 70% copper, 30% zinc and quickly deteriorates
when exposed to airborne pollutants. These pollutants cause the zinc to break down (dezincification) and that reduces
primer/powder sensitivity also. Keeping in mind your point of splitting the rim, improper storage will cause the brass to
revert to a more brittle state and split. So force is a critical factor.

To get the most out of rimfire ammo, store it in a water resistant, sealed ammo can with fresh dessicant. Don't open the
can needlessly, and if you have a second floor home, that's a great place to keep it as there is less humidity on
second floors. Yeah, yeah, I know old uncle Charlie and Zeb down the road shoot .22lr that was made during WWII. Good
for them, there are always exceptions to every rule, but nevertheless, it's best to properly store ammo.

BTW, H53EXPERT, I'm curious about that screen name. Are you an expert in the CH-53, MH-53, etc.?

Anyway, that's my two cents worth.

Ted

A lot of us buy cheap plinking ammo and get occasional misfires which fire when restruck with the rim in a different position.  That indicates the primer compound was forced to one side somehow, or not evenly distributed to begin with.  If it failed due to moisture, it would fail to fire when restruck, and the whole package, or most of the rounds in it would also fail to fire since they would have to have been exposed to the same moisture conditions as the round that failed.

Premium ammo rarely fails to fire because they take extra care in ensuring it is primed correctly.  Since it cost so much more, I do believe premium ammo has a tendency to sit at distributors, shops, or warehouses much longer than the cheap stuff.  If it was being effected by moisture due to those conditions, it would fail more often, not less.

I was trained as an A/D/E mechanic, even though the A model had long been retired by the time I went through training.  I had been a mechanic, line supervisor, collateral duty inspector, quality assurance inspector and plane captain on CH and MH-53s.  I was later a safe for flight maintenance controller, and then went on to become a reliability centered maintenance data analyst.

A lot of us buy cheap plinking ammo and get occasional misfires which fire when restruck with the rim in a different position.  That indicates the primer compound was forced to one side somehow, or not evenly distributed to begin with.  If it failed due to moisture, it would fail to fire when restruck, and the whole package, or most of the rounds in it would also fail to fire since they would have to have been exposed to the same moisture conditions as the round that failed.

Premium ammo rarely fails to fire because they take extra care in ensuring it is primed correctly.  Since it cost so much more, I do believe premium ammo has a tendency to sit at distributors, shops, or warehouses much longer than the cheap stuff.  If it was being effected by moisture due to those conditions, it would fail more often, not less.

I was trained as an A/D/E mechanic, even though the A model had long been retired by the time I went through training.  I had been a mechanic, line supervisor, collateral duty inspector, quality assurance inspector and plane captain on CH and MH-53s.  I was later a safe for flight maintenance controller, and then went on to become a reliability centered maintenance data analyst.

Good points all H53.

I did the airframe tooling string concepts for the G/D/E and the EAPS during my 30 years at
Sikorsky. I also did the preliminary manufacturing plan for "Special K" before I was
laid off. My dad was the senior rotor head mechanic for all of the VH helos
while in Overhaul & Repair at Shelton and Stratford Hangar. Nice to see your pride shows
still and, thanks for keeping them flying, thanks for your service.

Ted