Apex posts about part compatibility

Apex is reknowned for making S&W M&P parts, and with M&P Shield out they posted parts compatibility with their M&P parts.

Parts that work in M&P Shields are,
Apex Hard Sear
Apex Ultimate Striker Block  Kit(USB Kit)
Apex Duty/Carry Sear and Trigger Return Spring (DC Spring Kit)
(Apex sees no reason to install Comp AEK or Competition Spring kit since it is not what the Shield was made for)

Parts that do not work are,
Apex Forward Set Trigger and AEK triggers
Apex Failure Resistant Extractor
Trigger Pivot Pin

From: Apex