I finally got Hornady to issue a call tag to pick up the ammo, took three e mails and at least as many phone calls. here is their reply. I will have the gun checked out but for a 25 round box of ammo with 4-5 live ones returned I find the response well, so so.




I recently got the opportunity to look into your return of 9mm 115 grain Critical Defense ammunition. Misfires in a self defense handgun can be very unsettling and it is definitely a problem worth some attention.

In complaints of misfires there are a few measurements I look at that can give obvious cues as to what the problem is. The first measurement I took was cartridge headspace. Headspace is a measurement of a specific dimension of the the cartridge case that determines how the round will "seat" in the chamber. If a headspace is too long than the cartridge may not chamber at all. If it is too short there can be problems with misfires. SAAMI specification for headspace of the 9mm cartridge is .744" - .754". I measured the headspace of the misfired rounds you sent in and determined the headspace values to be .747", .747", .747" and .748". These are within specification and therefore I ruled out headspace as the culprit of this problem.

Next I checked the primers. To start with I will explain the term "all fire." An all fire is the depth that a firing pin must penetrate a primer for 100% reliable primer ignition. The requirement for an all fire is .017". I carefully measured the depth at which your firing pin struck these primers and found the depths to be .013", .014", .014" and .015". These strikes are very close to all fire limit and I think very well explain your situation. I'm assuming that the remainder of the box was shot successfully and the only misfires were sent to us.

Next I sent the misfired rounds down to our lab to be test fired. We do not have the specific model of Kahr in our inventory that you have. However, we do have a Kahr MK9 which seems to be a very similar design. All four of the misfired rounds fired on the first primer strike and functioned the gun flawlessly.

The .017" for an all fire is not like crossing a magic line and being able to say, "These are .016" and will never fire." Ammunition fired from guns that are striking primers in a very borderline manner can show this flip-flop behavior. Your firing pin penetration depths on the misfires were very close to the requirement for an all fire and I think the issue is simply that your firing pin is striking primers right at or slightly under the requirement causing an occasional misfire but usually firing successfully. Lastly this is also likely the explanation for why different ammunition works fine out of the gun as different manufacturers use different primers that can have slightly different hardness's. Our primers, while still in spec, are very likely a little harder than those in the Speer and Remington that you report as functioning fine. In short I would strongly suggest taking your firearm to a gunsmith or sending it in to Kahr for a quick look over. A few small tweaks to the firing pin or its spring is likely all it will take to make this gun 100% reliable with all types of ammunition.

As a result of being unable to find any defect in the ammunition itself I must hold off at this time in issuing a return. However, if you have the firearm checked and it comes back with a clean bill of health with no findable faults I would be more than happy to send you out a new lot of 9mm Critical Defense ammunition.

Here is most of what I wrote back:


I can not dispute your information as you have the instruments, technology and experience in measuring such things. But look at it from a customer practical standpoint.. You also "assumed the rest fired" which they did not. I rechambered several and restruck them, then they fired
As I believe I mentioned in my letter, I have fired over 400 rounds of ammo through this gun of many different brands, plus my own reloads using CCI, Winchester and Wolf primers and have never had a failure to ignite a primer. I buy your new brand and have a problem. Not a problem with feeding or ejecting which occurs with some guns/ammo combination, but failure to ignite which I have never had in a factory load. Photographs of the primer strikes shared with experienced reloaders all concurred that the strike was hard and deep enough that it should have ignited. I also mentioned that I re- chambered some of the misfires and yes, they did go off on the second strike which to me indicates a high primer. You did not mention this possibility in your report.

So the bottom line is that Remington, Winchester, PMC, Fiochi, MagTech, Speer, Federal, Blazer Brass, Speer, and reloads all fire, but only the new Hornady CD does not, therefore it's the gun? I find that difficult to comprehend.
I have every round fired written in a log by date, quantity and any noted failures.

I will relay your information to the members of several reloading forums I belong to as they were interested in the outcome.

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Still Running Against the Wind