Ar15 trigger pin walking out

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HRnightmare

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Today while in a class my trigger pin kept walking out during shooting, especially rapid fire.

When I got home I pulled the trigger pin and hammer pin out and noticed they are different. The THREE different guides of building AR's never mentions the difference.

One has a notch in the center and the other has it just near the end on one side.

Which one is which? Which way do you drive the pins in from and which way does the notch go on the one with the notch off from the center (mag release side or other side)?

Thanks.
 
The pin with one notch in the center is your hammer pin. The pin with one notch toward one end is you trigger pin.

A leg of the hammer spring rests in the notch of the trigger pin to prevent it from moving.

There are sometimes "issues" with this, as manufacturers don't always get location, thickness and, in the case of DIY assembly, hammer spring orientation right. It is possible to install it backward.
 
So does it matter if the right or left leg sits in the notch? Basically does it matter which way it is oriented?

THANKS for the info.
 
The pins will be correct from either direction.

Have you shot this particular rifle before? IOW, is this a new rifle or a new issue in an old rifle?
 
I have actually shot this rifle before many times...but this was in a class where rapid fire was necessary, all previous fire was at a very upitty range...one rd every second or two MAX...
 
It's entirely possible that everything is installed correctly, has made it through a lot of range time and either the hammer spring is slightly too large diameter, the retaining cut slightly too small or the hammer spring is a little out of whack and the leg contacting the pin needs to be bent a little to ensure the correct angle for proper retention.

If everything is as it should be and the pin is still walking out, I second the KNS pins. However, they can be had for a couple bucks less from several other vendors. Usually just under 30 bucks.
 
I had the same issue with one of the pins that came with my ALG trigger. I just replaced the pin with a generic cheap one and that solved that. I found that the ALG one was a bit undersized.
 
HRnightmare said:
When I got home I pulled the trigger pin and hammer pin out and noticed they are different. The THREE different guides of building AR's never mentions the difference.

One has a notch in the center and the other has it just near the end on one side.

.
Click to expand...

The standard milspec pin has two grooves in them. It does not matter whether it is installed in the hammer or trigger position.

I'd try different pins first before spending big bucks on anti walk pins. But whatever rings your bell. Who am I to talk, I spend money in ways sometimes that makes some folks cringe.
 
THANKS FOR ALL THE INFO.

If everything is as it should be and the pin is still walking out, I second the KNS pins. However, they can be had for a couple bucks less from several other vendors. Usually just under 30 bucks.
Click to expand...

I am going to try just installing different pins. Unfortunately as I often do, I rushed to bang out the pins to reinstall new ones and by the time I realized they are different, had mixed them up so I don't know if the wrong pin being used was the problem or not.

I do believe they are the pins that came with a non-factory trigger kit. I am going to go back to trying std milspec pins and if not try the KNS pins.

THANKS AGAIN!
 
Installed the KNS pins last night. I guess I dont understand why they need oiling...but ok.

Also I am not convinced they are not going to fall off of the notch that the part that does not get screwed in on (I believe it was the hammer pin side).

Finally, whats to keep the screws from vibrating loose and then the pins falling out?

Am I being over paranoid? Anyone have experience with these things?
 
I've seen pins walk out with mil spec components if the hammer spring was installed upside down, so that the legs didn't properly lay in the trigger pin's grooves.

I've also seen it when somebody clipped one of the hammer spring's legs while doing the "5-minute trigger job", then put the trigger pin in so that the ungrooved part was under the one remaining leg.
 
They are as cfullgraf described and should also solve the problem. Both pins have both of the needed grooves, so it doesn't matter which goes where. You can't mess it up.
Click to expand...

The pins that I had, that I believe came with a lower parts kit from PSA had one pin with one hole in the center and one pin with one hole to the side...

So I pulled out all my spares and they were all the mil-spec ones as shown in the picture.

I am sure just replacing them with new mil-spec pins would have done the trick but the more and more I read about the beating that SBR's put on lowers the more I do not regret the KNS pins (if they work)

I might also do one for my 9mm SBR AR
 
Can't go wrong with them.

attachment.php
 
Walkalong. Yours must be a different generation? Mine is more like a raised bar where yours is a thin line that conencts the two pins.

At first I didn't like the way they look but I think they will grow on me. I was afraid the raised hump would interfere with the mag release but I don't think thats a problem. Thanks.
 
KNS makes both types. They perform the same function, cost the same price and just look a bit different. The attachment is slightly different, but both a secure and won't cause problems.

Look at Midway's website and you'll find both types, Gen 1 and Gen 2. The kind you and I have are 1st gen, Walkalong has 2nd gen.
 
If you have a pin with only a single groove in it - center or offset - throw it away.
On a walking trigger pin - more often than not, I've found it due to a substandard trigger spring presenting too little tension to retain the pin properly. If the pin itself is correct.
Never had a correct hammer pin walk unless the retaining spring within the hammer wasn't present - seen that twice.

Other than those, nearly all the walking I've seen was due to improperly machined lowers or home builds with insufficient anodizing to harden the interior of the pin holes.
 
Thanks 1911 guy. I am thinking about doing the same things on my 9mm SBR AR. It also is suppressed most of the time.

My 5.56 AR is adorned in FDE furniture and my 9mm is all black. I am actually thinking of putting the KNS pins I have now on the 9mm and then doing FDE ones on the 5.56 lower. I think it would look cool.

Can you see that I way over evaluate things...I am super anal about my guns. I know, its weird.
 
I saw those on Amazon and thought about them. I was just more interested in the KNS because of the reviews. Everyone seems to love them. I found nothing negative about them except from people who didn't even own them claiming "it was a solution to a problem that didn't exist". Basically people talking out a hole other than their mouth.

I bought another set of the KNS for my suppressed AR SBR and they are the gen 2 with the thin connecting bars. I will see which one I prefer.
 
The KNS pins are really aimed at registered full auto lowers where wallowing out the holes from the pins rotating is a very bad thing. Over kill on a semi. The JP pins are all you need. If I had to do it over again, that is what I would have bought back then, being less ignorant now than I was then. :)
 
Gotcha. I already ordered the KNS and I think they will arrive today or tomorrow. Oh well, I will look at the other ones for the future. I'll consider the upgrade to the KNS as "extra insurance" haha
 
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