Anyone have experience with this style of AR firing pin retaining pin?

turtlehead · November 25, 2017, 11:41 PM

https://m.ebay.com/itm/5-56-Stainles....c100890.m2460

Getting a little fed up with the cotter pins.

Charlie98 · November 26, 2017, 12:04 AM

How have the cotter pins done you wrong?

turtlehead · November 26, 2017, 12:13 AM

Oftentimes they are difficult to put back in. And just generally a snotty attitude.

brasscollector · November 26, 2017, 06:55 AM

I had something like that come in one of my BCGs, maybe aero m5? I haven't seen a need to upgrade all of them myself. I do have my reservations on the cheapo cotter pins but they seem to hold up in my world, no need to reinvent the wheel.

Viper225 · November 26, 2017, 05:00 PM

If I remember correctly my old Army Issue M16 had that style retainer pin. I believe they went away in the very early 1970's along with the 3 Prong Flash Suppressor's.
I think they were just replaced when needed by the cheaper cotter pin that worked just fine. They look cool, but I have never replaced a cotter pin.

Bob

zukiphile · November 26, 2017, 05:37 PM

I prefer them. Nothing wrong with the cotter pin...unless the end gets bent up and it becomes hard to insert.

I suppose that if you had the right kind of nail, you could just clip it to length.

rkbanet · November 26, 2017, 07:58 PM

The military went to the cotter pin style because they have less of a chance of breaking than the solid ones. They have more give.

turtlehead · November 26, 2017, 08:03 PM

The ones in my link are stainless steel. KNS makes them out of tool steel.

Are they really under much stress?

ed308 · November 26, 2017, 08:26 PM

I've got one in my Aero 6.5 CM. They work. But so does the cotter pin.

marine6680 · November 27, 2017, 03:15 AM

The cotter pin is a wear item... replace them regularly, they are cheap if you buy a multipack.

The retaining pin is under impact stress, as the firing pin does impact it.

If the solid pins do not have enough impact and yield strength, they will break rather than absorb the impact. Its likely that any pin that is tempered and hardened to withstand impacts will behave much like the cotter pins do anyway. They may not get bent as much overall, but is that worth the cost increase?

bfoosh006 · November 28, 2017, 11:16 AM

If you twist the cotter pin while inserting it... it will be more user friendly.

As for those style pins... well, I would question the quality of those over a cotter key type.

They might be fine.... maybe...

I wouldn't want such an important part breaking... it retains the firing pin, which retains the cam pin... which needs to stay aligned in the upper receiver raceway.

So if it broke it might thoroughly bind up your AR.

If you buy something like that... buy once, cry once... in other words buy known quality from a company that can be held accountable.... not some guy on Google.

mellow_c · November 28, 2017, 06:16 PM

I think I have one BCG with a solid pin like that and it's good to go, but I haven't shot a lot of rounds with it either.

I agree that the cotter pins can be a bit of a pain. I also agree as stated above that if you push them in just a certain way with a bit of a twist it can help them go through the hole on the other side. I've even used a very small jewelers flat head screw driver to help press the cotter pin into alignment from the opening on the back side of the bolt carrier and it makes inserting it very easy, in the case that I run into one that is very stubborn and isn't responding to my twisting and supposed finesse. :-D

November 25, 2017, 11:41 PM	#1
turtlehead Senior Member Join Date: October 20, 2015 Location: Phoenix, AZ Posts: 1,203	Anyone have experience with this style of AR firing pin retaining pin? https://m.ebay.com/itm/5-56-Stainles....c100890.m2460 Getting a little fed up with the cotter pins.

November 26, 2017, 06:55 AM	#4
brasscollector Senior Member Join Date: July 26, 2015 Posts: 526	I had something like that come in one of my BCGs, maybe aero m5? I haven't seen a need to upgrade all of them myself. I do have my reservations on the cheapo cotter pins but they seem to hold up in my world, no need to reinvent the wheel. __________________ He may look dumb, but that's just a disguise. -Charlie Daniels

November 26, 2017, 05:37 PM	#6
zukiphile Senior Member Join Date: December 13, 2005 Posts: 4,449	I prefer them. Nothing wrong with the cotter pin...unless the end gets bent up and it becomes hard to insert. I suppose that if you had the right kind of nail, you could just clip it to length. __________________ http://www.npboards.com/index.php

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November 26, 2017, 12:04 AM	#2
Charlie98 Senior Member Join Date: September 6, 2006 Location: Great state of Texas Posts: 1,077	How have the cotter pins done you wrong?

November 26, 2017, 12:13 AM	#3
turtlehead Senior Member Join Date: October 20, 2015 Location: Phoenix, AZ Posts: 1,203	Oftentimes they are difficult to put back in. And just generally a snotty attitude.

November 26, 2017, 05:00 PM	#5
Viper225 Senior Member Join Date: September 20, 2009 Location: SC Missouri Posts: 663	If I remember correctly my old Army Issue M16 had that style retainer pin. I believe they went away in the very early 1970's along with the 3 Prong Flash Suppressor's. I think they were just replaced when needed by the cheaper cotter pin that worked just fine. They look cool, but I have never replaced a cotter pin. Bob

November 26, 2017, 07:58 PM	#7
rkbanet Member Join Date: April 16, 2012 Posts: 64	The military went to the cotter pin style because they have less of a chance of breaking than the solid ones. They have more give.

November 26, 2017, 08:03 PM	#8
turtlehead Senior Member Join Date: October 20, 2015 Location: Phoenix, AZ Posts: 1,203	The ones in my link are stainless steel. KNS makes them out of tool steel. Are they really under much stress?

November 26, 2017, 08:26 PM	#9
ed308 Senior Member Join Date: November 5, 2016 Location: DFW, TX Posts: 1,147	I've got one in my Aero 6.5 CM. They work. But so does the cotter pin.

November 27, 2017, 03:15 AM	#10
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	The cotter pin is a wear item... replace them regularly, they are cheap if you buy a multipack. The retaining pin is under impact stress, as the firing pin does impact it. If the solid pins do not have enough impact and yield strength, they will break rather than absorb the impact. Its likely that any pin that is tempered and hardened to withstand impacts will behave much like the cotter pins do anyway. They may not get bent as much overall, but is that worth the cost increase?

November 28, 2017, 11:16 AM	#11
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	If you twist the cotter pin while inserting it... it will be more user friendly. As for those style pins... well, I would question the quality of those over a cotter key type. They might be fine.... maybe... I wouldn't want such an important part breaking... it retains the firing pin, which retains the cam pin... which needs to stay aligned in the upper receiver raceway. So if it broke it might thoroughly bind up your AR. If you buy something like that... buy once, cry once... in other words buy known quality from a company that can be held accountable.... not some guy on Google.

November 28, 2017, 06:16 PM	#12
mellow_c Senior Member Join Date: January 7, 2008 Location: Colorado Posts: 1,862	I think I have one BCG with a solid pin like that and it's good to go, but I haven't shot a lot of rounds with it either. I agree that the cotter pins can be a bit of a pain. I also agree as stated above that if you push them in just a certain way with a bit of a twist it can help them go through the hole on the other side. I've even used a very small jewelers flat head screw driver to help press the cotter pin into alignment from the opening on the back side of the bolt carrier and it makes inserting it very easy, in the case that I run into one that is very stubborn and isn't responding to my twisting and supposed finesse. :-D