The latest consensus take is the striker safety can fail due to tolerance stacking in certain production runs.
Due to the nature of the higher spring tension and stored momentum of the P320's striker, when the striker safety fails, it can cause the gun to spontaneously fire.
Other striker-fired pistols (e.g Glocks and S&W Shields) have lighter strikers and/or less tension so even if their striker safety failed, it wouldn't be enough to cause a primer detonation.
> Other striker-fired pistols (e.g Glocks and S&W Shields) have lighter strikers and/or less tension so even if their striker safety failed, it wouldn't be enough to cause a primer detonation.
This is true of the Glock and some others; the striker is not fully cocked when the gun is ready to fire but the trigger is not being pulled. The trigger must be pulled to fully compress the striker spring, giving it enough energy to fire the primer. It does not appear to be the case for the Shield; the striker is fully cocked before the trigger moves.
Many popular striker-fired handguns operate like the P320 and Shield, including the S&W M&P, Springfield XD series, Walther PPQ/PDP, H&K VP9, and the Sig P365. None of those have a reputation for firing without something pulling the trigger, which suggests that the P365 is uniquely flawed in its design or manufacturing process.
My mistake. You are absolutely correct on the Shield.
The P320 striker still has more stored energy to dissipate in a striker-safety failure.
Ironically, this was a deliberate feature of its design submission for the M9 replacement program. In theory, this allows for more flexibility in trigger pull design (the trigger has to do less work) for even greater modularity in the FCG and less occurrence of light-primer-strikes.
The M9A4 is an amazing weapon, both in handling and design. It's heavy, sure, but that makes subsequent shots more accurate, less recoil. Different firing mechanisms though and to be fair I haven't shot the P320. But I love my M9.
I've only ever shot one on the range, but concur with the lack of recoil and easier follow-up shots. I can do hammers (controlled pairs) far easier than with a Glock 19.
Due to the nature of the higher spring tension and stored momentum of the P320's striker, when the striker safety fails, it can cause the gun to spontaneously fire.
Other striker-fired pistols (e.g Glocks and S&W Shields) have lighter strikers and/or less tension so even if their striker safety failed, it wouldn't be enough to cause a primer detonation.