This is something that I have never thought about at all until I stumbled across an old thread (didn’t want to necro bump it).
It was posted in this thread the turning the retaining pin vertically after installation increases the life of retaining pin. Is this true?
Ask yourself: “Why would it increase the life?”
The ‘pinch’ of the tines is the same. The head will always be below flush no matter what orientation (if the carrier and pin are made to spec).
The only possible reason I can see is it presents a stronger cross-section to on-axis loading by the firing pin. However, any loads by the firing pin are just the inertial load from the firing pin when the BCG stops at the end of the extraction stroke (and this is cushioned by the plastic snubber on the end of the buffer).
I started turning the head perpendicular to the path of operation after a discussion a few years ago. Haven’t seen a broken firing pin retaining pin since, but that’s a fairly low breakage part, and the ones I have seen break could be easily attributed to poor maintenance and assembly practices.
From Tapatalk:
Jack Leuba
Knight’s Armament Company: Military/Govt Product Liaison
F2S Consulting: Director of Shooting Stuff
I did ask myself that. A respected member mentioned it, which is the only reason I even gave it a second thought.
https://www.m4carbine.net/showthread.php?33630-Downsides-of-a-Non-Shrouded-Firing-Pin
Agree about being a low breakage point and it’s hardly something I’m worried about. I’ve got a number of ARs, I’m not gonna book it home to the safe and reorient every FPRP, lol. I am curious though. And it would be something I would get in the habit of doing after cleaning, if it made any difference.
In your discussions, what was/were the reason(s) that convinced you orienting the pin perpendicular to operation/vertical would make any difference at all?
Basically that simply turning the FPRP made it stronger with no negative effect. Couldn’t think of a reason that it wouldn’t be better, and experience supported that.
Certainly nothing worth losing sleep over.
From Tapatalk:
Jack Leuba
Knight’s Armament Company: Military/Govt Product Liaison
F2S Consulting: Director of Shooting Stuff
In a regular, shrouded M16 style carrier, this should be a non-issue. Those ramped carriers with type 2 hammers could chew up retaining pins pretty good though.
A point that not many think about really… I saw someone asking this once before but I never really thought about it too much though until then. I just always make sure the FP is secured with the RP set in fully by shaking the BCG upside down pretty damn hard.
On the flip side, if the pin is horizontal and it does back out slightly, the increased radius on the loop will tend to push it back in and scrape lessthan the smaller radius of the wire profile…
If, that was the case, then maybe so. The question is, does it have the tendency to back out? If anything, it seems to tend to pull inward from deflection. Not saying it can’t happen, but I would bet most wouldn’t see it unless something else was out of order. Even if it did, the radius of the pin doesn’t seem like it would make much of a difference.
If it is a concern, you can go with the pre-A1 solid retaining pin.
I’ve used both the cotter pin, and the solid pin.
The cotter pin is a lot easier to work with. I wouldn’t lose sleep over it. This is wine-tasting territory.
YMMV
It’s not a concern…genuinely curious, that’s all. I haven’t lost any sleep over this…lol.
About as much difference as difference in strength of the two legs in one direction or the other…
The solid pin works fine, but requires a punch or Glock tool to remove.
The cotter pin is far easier to remove.