Compression Lengths for Spring Testing

[ppknut]

Does anyone have, or know, the compression length(s) for replacement springs for an M&P 40. Some time ago I swapped the captured OEM Spring/rod for a Wolff spring set with their guide rod.

I was thinking about purchasing one of the spring testers and while the standard 1911 compression length (1.625") is easy to find, I haven't been able to find the same info on the M&P replacement springs (perhaps I need to call Wolff?).

Same question for a BHP recoil spring.

Thanks for any input.