Is striker assembly same between FS9 and Shield? Was gonna order a spare and curious if it would also work in the shield.

The answer is yes. This is an email I received from Apex, a year ago:

Here is all the intel we have pertaining to the M&P Shield:

What we know
When our Shield arrived here at Apex, it had a gritty pre-travel, hard break and relatively long over travel, yet a distinct reset. Upon detailed disassembly and inspection, we noticed the following parts interchangeable between the Shield and the full size M&P.

Sear
Sear Spring
Sear Plunger
Striker Block
Striker Block Spring
Striker Block Washer
Trigger Return Spring
Striker Assembly
Extractor Pin


Bob