What spring is this. MP9 2.0 Compact Compliance.

[WarDawg]

Just got this pistol. It has a spring my full size does not have. It goes to the the slide stop. It’s the red spring. What’s the story ?

 

[WarDawg]

From a lot of searching it seems the Compact models have this spring. Full size does not. Reasoning might be the lever under recoil could trip the slide lock lever. Not saying that’s 100% but makes sense. Wardawg.

 

[Saudade]

Yep, slide catch/stop spring. Why one and not the other? Possibly just due to production changes, inventory, who knows. MGW does show the lever with the spring for the full size M&P 2.0 but it's marked OOS. Since the 2.0s use a detent to hold the slide catch in place, a spring may not be needed. Hopefully some other 2.0 Compact folks chime in.