Howdy folks,
Since you are asking for opinions/experiences, I will share mine with you. First, I think it simply depends on the individual pistol, rather than a particular brand primarily.
I have owned some pistols that clearly stated in their manual that a break-in period was required. One example of this is a Karh K series. However, I fired my Kahr and never had the first malfunction from its first round to present.
My experiences with my CZ pistols have been the same, as I have fired all of them, and have never had a malfunction - when I was firing them. But I did allow a fellow shooter to fire 3 of my pistols on our first outing together (two CZs and an FH HP), and noted he had the same malfunction you initially described with each of mine. These were the first malfunctions for each pistol. But as a 3.5+ decade police firearms instructor, I could clearly see that he had limped wristed with each pistol, and this had caused each malfunction.
I also watched him then fire two of his personal pistols, and noted he had the same type of limp wrist induced double feed malfunction with each of his own guns as well. I later discovered that he suffers from a bad case of carpal tunnel in his wrists.
My understanding of the basic design of most pistols is that they need the full force of the recoil power to function as designed. When a shooter allows his wrists to absorb any of this energy, any pistol can and often will malfunction.
Now I am certainly not trying to imply that any shooter who experiences a double feed malfunction has clearly limp wristed. You also mentioned that your friend was using Winchester FMJ at the time. You did not specify if it was white box or value pack ammo. I have often read on various sites, where lots of various company's ammo (Winchester and Remington value packs are two examples) that do not meet all quality control specs, are then sold as value pack ammo at a reduced price. Given the fact you normally obtain 100 rounds or 50 at a reduced price, it is a bargain. But I think the round is specifically intended to be only a practice round too. This is not an attempt to "trash" any company's value pack ammo. Just an observation that it is possible the double feed malfunction could have been caused by a round that was perhaps a bit under-powered too.
You asked for possible explanations for what could be the cause of these two malfunctions, and I am simply trying to suggest some possible ones. If you consider yourself a more consistent or stronger shooter (technique-wise) than your buddy, and if his malfunctions seem to continue on in the future, you might consider doing a range session with his pistol for him too. If you are certain you do not limp wrist, and your session fails to produce a malfunction - then you probably have eliminated one possible reason. If he then continues to have a rare malfunction, it may need more "break-in" or an inspection by someone for parts issues.
Hope this might help a bit anyway sir.
twoguns
