Shadow 2 Carry FTF Fix After 3 Warranty Trips
Writing this as a documentation for anyone else who unfortunately got a lemon in the form of a Shadow 2 Carry and had multiple failure to feeds. To me it seemed ammo dependent but even higher grain rounds weren't guarantee to improve reliability; FTFs were bound to happen 2-3 times per mag. It was very annoying to deal with so if anyone is experiencing this I hope it can help you resolve it in anyway.
>First CZ warranty report: "Field-stripped and inspected firearm. Adjusted breech-face lead-in and extractor edge for feeding issues. Cleaned, oiled, and inspected firearm. All OK"
Honestly felt like they did the bare minimum here. It didn't resolve much so I sent it in a second time like 2 weeks after getting it back.
>Second CZ warranty report: "Honed chamber and adjusted barrel throat. Adjusted and polished breech face lead in, barrel hood and feed ramp."
This was what I had initially hoped they would have done in the first RMA and so when I got it back I was hopeful. From what I remember, this slightly improved the reliability a bit and I wasn't getting as many random FTFs in the middle of firing a mag. However, I still noticed that hand-racking the first round AND firing until the very last round in a magazine would cause FTFs, so I wasn't satisfied and sent it in a third time.
>Third CZ warranty report: "Inspected, based on video provided by customer, issue is mainly from initial loading and final round in magazine. Both issues seem to indicate an issue with the cartridge not rotating correctly into the breech face of the slide. Noted heavy brass shaving at firing pin recess, removed sharp burr causing the specific drag indicated. Additionally, replaced the extractor and adjusted for smoothest possible feeding... Function tested and test fired 60 rounds (4 magazines) of Federal American Eagle 115gr ammunition, loading both slowly by hand and quickly slingshoting, all rounds fed smoothly including the first and last rounds."
This might somewhat have explained why Blazer ammo was very consistent, while anything else (like S&B, Magtech, etc.) were more prone to FTFs: The primer for those are perhaps more pronounced or harder and thus slowed the rotation and sliding in as they cycled.
I've shot 200 rounds and haven't seen a FTF. In the back of my mind I'm still skeptical of it, but I'm definitely a lot more relieved my $1200+ CZ isn't worse than my ~$600 Glock-clone (MR920).
TL;DR: CZ honed the barrel chamber and adjusted throat, and found a burr in the firing pin hole which would cause drag when the bullets would cycle. Slowing down the bullet and not sitting properly in the breach face and extractor.