Well, this sucks

I wont use KNS pins on anything. They are pointless and require a tool to remove, making them inferior to the milspec pins.

I just Googled images of the lower. It is a pretty darn good looking setup. Time for a different trigger.

Jackal said:

I just Googled images of the lower. It is a pretty darn good looking setup. Time for a different trigger.

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I'd rather use the SSA trigger and forget the KNS pins...

Although the lower is milled to make the KNS pins look integrated they are the same length as standard pins. Are you sure you can just use standard pins. It may look a little strange with the cuts.

I have four Geissele triggers in four ARs all using KNS pins with ZERO issues. Who cares if they require a "special" tool (also known as an allen wrench) to remove since there's no need to remove a Geissele trigger once installed.

Buy a less expensive forged lower, sell the billet and use the money towards getting more parts

Or keep the billet and start on a new build.

Is the advice to not use the pins a true mechanical issue or something based on a "political" disagreement? Sounds like the latter if somebody else is doing it with 4 and has no issues.

Some vendors don't like supporting products they disagree with - and back it up by pulling the warranty. Doesn't mean it won't work. You won't know until you try.

Personally, I'd skip the Geissele. Hyperfire and Timney are nicer triggers anyway.

Why does Geiselle recommend against using KNS pins?

Every AR I own has KNS pins and aftermarket triggers (albeit no Geiselles), and I can't think of a reason why it wouldn't work perfectly.

I don’t know about the OP’s specific lower situation but I had the SSA trigger in one rifle and I’m also a big fan of the KNS anti-rotation pins. I called KNS a few months ago because Geiselle advised against using the anti-rotation pins with their triggers. I then called K&S and they said they were working with Geiselle to develop the pins but I never followed up on it because I off loaded the rifle with the Geiselle SSA.

I’m currently using the KNS anti-rotation pins with the ALG Defense triggers in two different carbines without any issues. For those that don’t know ALG Defense is the sister company of Geiselle, in fact I believe it’s his wife’s company. I didn’t ask ALG so who knows what their thoughts are? Lastly to answer try and answer post #12 I believe his has to do with the grade of stainless steel according to K&S but like I said I never followed up.

Tirod said:

Is the advice to not use the pins a true mechanical issue or something based on a "political" disagreement? Sounds like the latter if somebody else is doing it with 4 and has no issues.

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ADCO (a Geissele dealer) seems to be the only one pushing this agenda. If you read the text in the link ...

https://www.adcofirearms.com/acc/Geissele_KNS.cfm

.... you'll notice this comment.


"Geissele SSA pins are 0.1550" dia 0.0001. Holes in the trigger can be 5 tenths over Geissele pin size. Kns pins are either .154 or .1555. So they are either too loose or just about a metal to metal fit in Geissele triggers."

From a tolerance stack and manufacturing point of view his comment makes no sense at all. As I stated, I have four ARs with Geissele triggers, all with KNS pins, thousands of rounds fired, both suppressed and non suppressed, and zero issues. If I were selling Geissele triggers and wanted to reduce the number of calls, or reduce the chance of a customer return, I would most likely say that Geissele triggers should only use Geissele pins. That way, Geiselle would have to deal with any issues relating to performance. It's telling that ADCO doesn't sell KNS products.

Only other thing I can imagine would basically be a dielectric reaction between the materials used, but that would be a true oddity since everybody uses the same materials or at least very similar ones. Like others have said, it's been tried and proven to work. Assemble and enjoy.

Bottom line is that anti rotation pins just aren't needed in most AR's. They are intended to prevent wear of the pin holes in high round count full auto receivers which are basically irreplaceable, unlike a fifty dollar semi auto lower. So in most non-NFA AR's they're just a waste of money. Installing a high quality trigger will do much more for you than worrying about the pins.

Only other thing I can imagine would basically be a dielectric reaction between the materials used

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Do you mean electrolytic corrosion/erosion? Dielectric simply means polarizable insulator.

Regardless, electrolytic corrosion in the absence of an electrical field requires current-generating friction from motion-a lot more motion than triggers and hammers have. Basically, you're talking about static electricity.

I think he means galvanic corrosion which would simply require a conductive solution (electrolyte) and dissimilar metals. Heck, even a single alloy immersed in an electrolyte can experience galvanic corrosion (pitting) due to the presence of cathodic intermetallic particles. Anyway, ARs are full of dissimilar metals with the steel trigger and stainless steel pins being the least of my concern.

MachIVshooter said:

Personally, I'd skip the Geissele. Hyperfire and Timney are nicer triggers anyway.

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This is certainly a matter of opinion.

I have a Geissele SSA, a Timney, a CMC, a Wilson Combat and had an Armalite and Hyperfire. I had the base model Hyperfire rather than the 24c, but I was VERY disappointed with the Hyperfire. I couldn't predict when it would release and got rid of it in favor of a SSA. I'm keeping the SSA.

My favorites are the Timney for 3-gun/action/practical shooting and the Wilson Combat 2-stage for precision.

As for the KNS pins, I'm not really sure what they are for since I've never had a problem with Mil-spec pins. I'd be in favor of keeping a good trigger versus getting rid of the trigger in favor of using a set of pins. Maybe just try using the KNS pins anyway. If they don't work, ok, get a regular set.

Geissele advised not using KNS with their two stage triggers because the pin diameter was too small causing the triggers to feel a bit mushy from the play. The KNS pins were also soft, causing other problems. Geissele sent out explaining the problem and Adco had a copy on their website. I'm not sure if it's still there.

KNS has stated they were working on the problem, but nothing official has been said since

Time for a different trigger.

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Wow. Lots of really bad advice on here. KNS pins are not required if you assemble your trigger group correctly. Period, end of story.

This is certainly a matter of opinion.

I have a Geissele SSA, a Timney, a CMC, a Wilson Combat and had an Armalite and Hyperfire. I had the base model Hyperfire rather than the 24c, but I was VERY disappointed with the Hyperfire. I couldn't predict when it would release and got rid of it in favor of a SSA. I'm keeping the SSA.

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Never played with an earlier generation, but I am extremely satisfied with the 24 3G. 2, 3 and 4 lbs options; I have mine set up with the 2 lb, and it really does break clean at 2.05 lbs. It's in my 22" bull barrel, and I couldn't be happier with it (especially considering the deal I got at $180).

Timney is the gold standard, though, IMO. Always a great choice for any rifle, including ARs.

HKGuns said:

KNS pins are not required if you assemble your trigger group correctly. Period, end of story.

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No one has said that they're necessary. The OP isn't asking if they're necessary, simply if they will adversely affect trigger performance since his lower has "cut outs" for them.

As for statements such as the "KS pins are too soft", without actual data such as hardness, such statements are conjecture.