I recently acquired a M659 in a trade. Not knowing the round count, I'd like to replace the recoil spring before I take it to the range. Any suggestions on what "weight" Wolffspring I should purchase would be much appreciated. I don't plan on firing any +P ammo. Would standard factory spec. be ok, or maybe a 16 or 17 lb.? I'm clueless about this. Thanks.

14lb recoil spring is stock and works well with standard velocity ammo . With the cost of shipping its a good time to get any other springs or mag springs you may need or just buy a service pak Type 2 .

Thanks for the advice, hardluk1. I did, indeed, buy the service pack from Wolff. The 659 is in great shape, but is 30+ years old, so I'm gradually going to accumulate a supply of spare parts "just in case". Also bought a new barrel bushing for it.
One further recoil spring question: will the factory standard spring be ok for both 115 gr. and 147 gr. ammo (both non+p)?
Thanks again.

I acquired a 659 from my Uncle, retired cop
Just perched a spring PAC from Wolff springs
Fantastic gun

Sorry for the slow reply . I don't visit here often . Yes the 14lb spring should be fine with standard velocity 115 .124 and 147gr but there always a chance for a few issues for the first 50 to 100 rounds if loads are on the lighter end . To much of todays ammo is of marginal quality at times .