Does this ammo that you’ve been using have sealed primers?
Chambering a round on a lubed bolt, and then leaving it in the chamber, or not wiping it off may allow lube to penetrate the primer pocket(over a time period) and deactivate the round.
It may have nothing whatever to do with the firing pin.
However, if you do want a spring-loaded firing pin, you might look into trying to find one of those $5000 HK 416 uppers that made it into the states. They have a spring loaded firing pin and piston operation too. Not that I’d recommend either of those things personally, but you can get them with the HK if for some reason you’d want things like that.
The spring loaded firing pin doesn’t do a thing for you, but it sets worried people’s minds at ease.
Also, I fully concur with not repeatedly re-chambering a round.
HK416’s do have a spring loaded firing pin, but it is in conjunction with a hammer actuated firing pin block. (Talk about firing pin safety!)
Not that it adds anything to the discussion… but, I don’t think you can include the 1911 in the free-floating firing pin club.
The 1911 firing pin has a spring.
Somebody need to spend a hour at the range loading a single round in an AR a hundred times to see if it makes a difference…
Who here doesn’t have a life???
I’d like to read that report… :rolleyes:
I’m of the opinion that there’s no such thing as an “accidental discharge”, only a “negligent discharge”.
Even if there is a weapon/ammo malfunction, that’s no excuse for poor muzzle control.
The only way to get injured/killed by a malfunctioning weapon is to be in the bullet’s path.
MASP7- arrrggghhhhh! You are of course correct. I have only carried a 1911 for a good portion of my adult life, so you would think i was more astute then that.
I cannot imagine a scenario where a fall gives the firing pin enough inertia to fire the primer. If I threw an M4 out of a C130 at 10000ft, it reaches terminal velocity, somehow lands at 90 degrees muzzle perfectly to ground, the firing pin still wouldn’t be moving as fast it does during normal operation… as the bolt group does, recipicating during the cycle of operation.
The report is highly suspect & likely not looked at seriously due to: the time of incident (early invasion), lack of available investigative resources, lack of understanding of the system, much more pressing matters for the command, wanting to preserve some personalities image, most likely some combo of the above.
A safety knocked off by swinging back & forth on a troops back, & trigger caught on gear is more likely… all complicated by a fall… or maybe the rd’s impact caused the fall. I’ve seen ND’s like this twice. The heavier SR25 varients are more prone to this.
I get a FTF when I go full auto and this happens on the 2nd round, sometimes third or forth round. A round is chambered and the hammer is down but the round did not fire. Upon inspection the primer has a very slight indentation and my first thought is that the hammer followed. The rifle works fine on semi-auto but has not yet worked properly on full auto since it was built. I have been reading about “bolt bounce” somewhere in this forum but failed to get details that makes it comparable with my situation.
I am hoping to get some inputs here for the mean time since it’s still tomorrow that I can go to the range and try an H3 buffer and see if it goes full auto.
The light dimple on the firing pin is normal in ALL AR’s and M16’s as the firing pin is floating and taps the primer during chambering.
Hammer down over a live round can be either hammer follow or bolt bounce.
Try the heavier buffer.
It will slow down the cyclic rate and eliminate the bolt bounce if that’s your problem.
It can also be sear timing. (releasing the hammer too soon)
Check that with a pin gauge. (I forget what size)
Does the fire control group have all the proper pieces where they belong?
Remove any magazine and ammo from the gun.
Set the selector on the full auto position.
Drop the hammer with the trigger (you did check to see the chamber was empty right?)
Now you need your timing gages ( The cheapest is drill shanks at the required dimensions. I use three, one early timing gage .12 dia, one correctly timed gage .10 dia, and one late timed gage .08 dia.)
Secure the trigger in the fired condition (rearward) with wire. Using the charging handle pull the bolt carrier all the way to the rear but do not let it go, slowly lower the carrier towards the front until you have a 1/2" gap left between the carrier and barrel extension.
Insert the early timed gage in between the colt carrier and the barrel extension (not the bolt head) and slowly lower the bolt carrier with the charging handle. If the auto sear releases then your gun is out of time (early) and will most likely give you light primer hits. If not go to step 7.
Slightly retract the charging handle and remove the early gage and insert the late gage. Slowly lower the carrier until the carrier rest on the gage that is between the bolt carrier and the barrel extension. The hammer should have dropped, if it did not the gun is out of time (late) and will most likely either not release the hammer or act sluggish and have a slow cyclic rate. If it dropped go to step 8.
Pull back on the charging handle and recock the gun while removing the late gage. slowly lower the bolt carrier with the “go” or correctly timed gage until the bolt carrier rest on the gage that is against the barrel extension. The hammer might release or might not.
This same system could be used to check the timing of a M-16 or RR AR-15 using a traditional auto sear as well. The key is to set the timing so the hammer falls with the 0.10 diameter gage but not the early gage. Assuming that the hammer was released on this gage but not the early gage the gun is timed.
Pin gauges are short round steel pins that are precisely ground to specific diameters.
I have pin gauges from 0.060" up to 0.500" in 0.001" steps.
They generally come in a large sets like this:
I am now in the process of getting those gauges, .08", .10", .12". As these are fairly expensive, I am having then ground by a machine shop and am considering having them hardened. I sort of have free access to minor works in machining.
As an update to my previous post, I have not yet tested the unit with an H3 buffer and have decided to first check the auto sear timing just to be sure.
