View Full Version : firing pin designs... why the change?
Gents,
I have been curious about this for a while, perhaps someone can enlighten me as to why the original Stoner designed firing was redesigned... Specifically, the end of the pin that is hit by the hammer changed from a cone shape to a rounded knob shape. Finally, why did H&K decide to utilize the earlier cone shaped design?
Examples:
http://black-market-parts.3dcartstores.com/firing-pin-BMP416-44_p_293.html
vs.
http://www.brownells.com/.aspx/sid=12957/pid=5554/Product/Firing-Pin-AR-15?utm_medium=shoppingengine&utm_source=googlebase&mc_id=10000&gdftrk=gdfV21820_a_7c187_a_7c3466_a_7c231000005_d_231000005_d_10859
I have been thinking about ordering a few of the earlier style pins to compare and test in my SBR - what say ye?
The extra height is required to function with the 416's firing pin safety mechanism. There is no reason to include one in a regular AR carrier and plenty of reason not to. A standard, chromed pin from BCM will get you by just fine. Forever. And dont try any other stupid crap like taking down the extractor pin with the firing pin tip when you get a normal one.
I don't know the actual idea, but if I had to wager a guess, it had something to do with pricing. Any shape, other than a straight line, will require more machineing time. The older pin design looks a lot like the new one (material wise) but after making the pin, they then milled the cone on the head. The new version looks like they just omitted the cone operation, but left the material there (thicker). I would bet this was part of a package of upgrades done in order to either reduce cost or manufacture time.
CumbiaDude
02-08-12, 22:44
There is no reason to include one in a regular AR carrier and plenty of reason not to.For the sake of completeness, what are the reasons not to? :)
It aint broke. Dont fix it.
This isnt an issue of "oh well, I know it aint broke but perhaps we could extend its functional life by another couple hundred rounds." Standard firing pins usually outlast their operators, IF they dont they cost a few bucks to replace and they function just perfectly. There is no reason at all to go messing around with it. And this is beyond messing around with it. Not only do I see no benefit to a 416 pin in a carrier without a firing pin block, but it could potentially malfunction or damage itself or other vital weapon components. Just. No.
CumbiaDude
02-08-12, 23:57
Oh, so you don't have any specific reasons, you just see no benefit and fear it might cause a problem? :)
Whootsinator
02-09-12, 01:33
Oh, so you don't have any specific reasons, you just see no benefit and fear it might cause a problem? :)
Sounds like a plenty good reason to me.
The extra height is required to function with the 416's firing pin safety mechanism. There is no reason to include one in a regular AR carrier and plenty of reason not to. A standard, chromed pin from BCM will get you by just fine. Forever. And dont try any other stupid crap like taking down the extractor pin with the firing pin tip when you get a normal one.
Care to elaborate on this? I wasn't aware firing pins were chromed...
Please do correct me if I am wrong. It is my understanding that standard AR firing pins, regardless of the exact design and dimensions of the collar/rim, receive a chrome plating. I cannot locate an online copy of a Mil STD to cite. Please let me know if you do.
CumbiaDude
02-09-12, 15:37
Sounds like a plenty good reason to me.I agree that if it ain't broke, don't fix it, but my impression from his initial statement of there being "plenty of reason not to" was that he had specific reasons it would cause failure, and I wanted to learn more about these potential problems. I see now that wasn't the case, he just has vague worries about the unknown. :)
Guys, thanks for the responses...
I do see the point with regards to the extra machining step.
I don't see the point of folks guessing and reiterating "if it ain't broke don't fix it" B.S. It's my ****ing rifle, my life does not depend on it, and I want to know from people who have used a cone firing pin what the difference is - end of story. So don't chime in with the gun will explode if you install this part B.S. because frankly if I break the gun I'll build another, and will learn something in the process.
BTW, the link I sent is for a "clone" firing pin, not a real H&K 416 firing pin that has to disengage the safety lever added to the BCG. In fact, its the clone 416 firing pin from the now defunct Titan Defense entity. (This is what happened to the parts they made) So, since the cloned Titan 416 upper did not have the firing pin block system, the link I provided is for a firing pin that will work in any AR15 that uses a regular firing pin. I have handled a real 416 firing pin from an upper and it will NOT work in a regular AR as H&K specifically machined a large radius in the shaft of the pin where it transitions to the first "spool" - blocking it from being mixed up with a regular AR15 pin. They also changed a few of the dims around specific to the redesign of their 416 rifle as possible improvements to the original design. The clone 416 firing pin is the exact same dims as a regular pin minus the cone end...
I will ask again, to see if there is any other information that surfaces besides cost savings. I mean why did they design it that way in the first place?
I see your point. I did not understand that you were planning on using a Titan pin instead of at least one with HK dimensions, if not genuine HK. In that case, I expect that it will work just fine. ...Just like a normal pin.
I respect your interest in the history of the design and curiosity about the conical ass of the pin. What I cannot understand is why this mere curiosity leads you to want to put one in a gun you own. You can do whatever you like with your money and your property. Just trying to save you some money and possibly trouble, here. You can defend this conical design till your dying day... The point will always remain valid: there is absolutely nothing wrong with a normal pin.
Cesiumsponge
02-10-12, 03:13
There is no additional difficulty in manufacturing one design or the other, or any "extra step" in machining involved other than a slight modification of the toolpath on the sub-spindle side. These parts would all be done in a CNC swiss screw machine. The difference in cycle time would negligible.
Pax I appreciate the addition response, I should have clarified the part. However, my main objective with this thread is not to find a better wiz-bang firing pin, it is to try and understand why H&K used a cone end pin instead of the knob end like everyone else. Remember they went to the drawing board and evaluated every component of the rifle for their redesign, and they ended up with a cone pin design - which is what was original to the rifle. So, there is our Scooby-Doo mystery I'm looking to solve.
Straight Shooter
02-10-12, 08:11
Im now wondering what the heck is wrong with using the fp tip to remove the extractor pin, especially if Im squeezing it tight together
and simply pushing it out with the tip.
You don't want to risk creating a burr or sharp edge on the FP tip which could result in reducing it's ability to ignite primers. Now back to our regularly scheduled programming...
Im now wondering what the heck is wrong with using the fp tip to remove the extractor pin, especially if Im squeezing it tight together
and simply pushing it out with the tip.
Over the years I've seen 2 Sailors break the tip of the firing pin while using it as a punch for takedown. Most everyone has probably used it for takedown over the years once or twice. However, it's simply not the prudent thing to do.
SpaceWrangler
02-10-12, 21:53
Over the years I've seen 2 Sailors break the tip of the firing pin while using it as a punch for takedown.
I believe I've found the problem.
http://img.photobucket.com/albums/v638/Stretch67/cheeky-smiley-025.gif
I believe I've found the problem.
http://img.photobucket.com/albums/v638/Stretch67/cheeky-smiley-025.gif
Knockin' on the Navy, huh:lol: That couldn't happen with a jarhead or hua, no never! I will add that these "Sailors" are truly what we call ourselves, dirt Sailors. The only ship most of us were ever on was a cruise ship.
For what it's worth, I was trained in the military to use the firing pin as a punch to remove the extractor pin. Now, this shouldn't require anything more than a gental push to get the pin out or just the last bit in. If you are using it for more than this than yes, the pin will most likely be damaged. I have done it this way for years and see no damage to the firing pin. I think some are more zealous about doing it than I if they are damaging their pins in the process.
sinlessorrow
02-11-12, 13:41
Gents,
I have been curious about this for a while, perhaps someone can enlighten me as to why the original Stoner designed firing was redesigned... Specifically, the end of the pin that is hit by the hammer changed from a cone shape to a rounded knob shape. Finally, why did H&K decide to utilize the earlier cone shaped design?
Examples:
http://black-market-parts.3dcartstores.com/firing-pin-BMP416-44_p_293.html
vs.
http://www.brownells.com/.aspx/sid=12957/pid=5554/Product/Firing-Pin-AR-15?utm_medium=shoppingengine&utm_source=googlebase&mc_id=10000&gdftrk=gdfV21820_a_7c187_a_7c3466_a_7c231000005_d_231000005_d_10859
I have been thinking about ordering a few of the earlier style pins to compare and test in my SBR - what say ye?
how is that even legit? did they purchase the patent for those parts? i mean i see HK416 uppers that are identicle in all things but markings
Heavy Metal
02-11-12, 14:14
It was to remove mass and lessen the slam-fire risk.
For what it's worth, I was trained in the military to use the firing pin as a punch to remove the extractor pin. Now, this shouldn't require anything more than a gental push to get the pin out or just the last bit in. If you are using it for more than this than yes, the pin will most likely be damaged. I have done it this way for years and see no damage to the firing pin. I think some are more zealous about doing it than I if they are damaging their pins in the process.
Use the firing pin retaining pin instead. It's long enough to push the pin completely out of the bolt and less likely to be damaged.
Since most or all of the answers thus far have been speculation I'll jump in with my own.
If you compare the conical and rounded firing pins with regards the way they interact with the hammer you can see a possible reason for the change. As the hammer swings through its arc it will impact the conical pin on the sharp edge on the top (end)of the cone. Since both the hammer and the pin are hardened, sooner or later something is going to round over or chip off the pin or an indention will develop on the hammer face. Like a chisel that gets hit by a hammer many times over.
If the pin chips, you then have metallic debris (however small it may be) floating around in you lower waiting for Mr. Murphy to tell it when to jam things up. If the hammer face becomes indented it could provide a "catch edge" that could snag on the firing pin and slow the hammer enough to cause light strikes.
If you round the end of the pin most ,if not all, of those potential problems go away.
Granted that with the firing pin being free floating this could take a long time to manifest itself. In all honesty it may never manifest in a semi auto only weapon. However in light of the fact that these were designed as weapons of war with lives at stake, it's better to be safe than sorry.
Feel free to argue the logic if you see any flaws.
EDUB
Heavy Metal & EW1066,
thanks for the insight, I appreciate the on topic reply and the fact that neither of you fell into the "let me shit in this thread with bull shit talk of shit that has nothing to do with this thread" category.
I see the logic in lightning the pin and changing the angles so close to the hammer strike face to avoid possible fracture or eventual failure. What still baffles me is why H&K chose to keep the design for it's 416 series rifles...
I would think that if there were serious deficiencies in the design of the AR-15 firing pin, we would have seen a new design decades ago. All you have to do is look at the problems associated with the BAD lever to see how even a simple idea can sometimes cause problems. I see no reason to try a new firing pin design when the old one is working so well.
patrick sweeney
02-21-12, 14:32
OK, the reason why HK made the firing pin that shape it is? First, let's back up a step.
Having decided to make a "better" AR, the full Germanic engineering mindset kicks in.
Even doing something as simple as making their own AR upper, they (in all likelihood) considered every surface, every angle, every radius, and every alloy, heat-treatment and surface finish. I would not be the least bit surprised to find honest-to-god computer mainframe time devoted to cycling simulations.
In the end, they made a rifle that was heavier, with stronger springs, and the extra feeding/chambering forces required a firing pin lock to control slam-fire possibilities. "Is there a chance of one slam-fire in ten million chambered rounds? Yes, then we put in a firing pin safety."
They made the firing pin the shape it is, for what seemed to to them to be good engineering reasons. Can we ever know those reasons? Nope. Unless you find the HK engineer involved, shoot him up with truth serum, and threaten to key his beemer if he doesn't talk, we won't know. And even then, he'll probably give a decoy answer.
It is what it is, accept it and move on.
As for the other firing pin, if it was made to go into a standard carrier, and not need a FP safety, then it will in all likelihood work just fine. Knock yourself out.
OK, the reason why HK made the firing pin that shape it is? First, let's back up a step.
Having decided to make a "better" AR, the full Germanic engineering mindset kicks in.
Even doing something as simple as making their own AR upper, they (in all likelihood) considered every surface, every angle, every radius, and every alloy, heat-treatment and surface finish. I would not be the least bit surprised to find honest-to-god computer mainframe time devoted to cycling simulations.
In the end, they made a rifle that was heavier, with stronger springs, and the extra feeding/chambering forces required a firing pin lock to control slam-fire possibilities. "Is there a chance of one slam-fire in ten million chambered rounds? Yes, then we put in a firing pin safety."
They made the firing pin the shape it is, for what seemed to to them to be good engineering reasons. Can we ever know those reasons? Nope. Unless you find the HK engineer involved, shoot him up with truth serum, and threaten to key his beemer if he doesn't talk, we won't know. And even then, he'll probably give a decoy answer.
It is what it is, accept it and move on.
LOL, you nailed it! I work for a German manufacturing company and deal with this mentality almost daily. Rest assured, someone at H&K had their reason for changing the FP shape. This reason is likely well-documented, but this documentation may never see the light of day...
Zee Germanz... Zey alwayz sink zey ar rrrite.
Could it be more mass for more momentum to hit primers harder? Add the firing pin stop to eliminate the slam fire risk.
Well the larger the mass of the object the more energy will be required to accelerate the object when compared to one of less mass... so that isn't it. I think it has something to do with the cone design itself acting as a "ramp extension" to the carrier when the BCG moves backward and begins the unlock process while it is pressurized...
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