M&P 2.0 10mm 4 inch recoil spring weight

[3gunNoob]

Hi Guys,

I am already replacing my Mags with beefier springer precision magazine springs. I dont know the factory recoil spring weight. (searched everywhere). Does anyone know the factory weight and what spring weight is recommended for shooting underwood 155 grain. Galloway Precision makes assembly for m&p. 

 

Also, I am convinced that S/w magazine springs compress their way to failure. I shot 250 rounds without failure and then it started. 

 

Please help me with the recoil spring weight for hot loads.