9mm springs

Does anyone have any insight as to what combination of main and recoil spring weights would be best for a 9mm with a slide mounted optic?

BE pistols vary for spring weight. Why? Is it loose fitting barrel or hard match fit. Lockup/unlock timing has a result on recoil (slide velocity). Match pistols I build are running 10# springs for either irons or optics. I fit barrel to function for sights/optics being used. So I recommend you try an assortment of springs. 
Jon

It's a hard fit match barrel. I put some springs I had in my parts bin. Unfortunately I don't know their strength. I think the recoil is a 10 pound but I have no inkling the strength of the main. I had some soft hits at the range. The only other mains I have are 20 and 21 pound mainsprings. Once in a while it stovepipes so I ordered an 8 and 9 pound recoils. I'll try the 21 pound main and one of them and see what happens.

If your not sure what you have to start with how can you choose a path to correct the problem?

Got to be careful going below 10# on recoil spring. You start losing lockup time in battery and groups will grow at 50yds.
Jon

Stovepipes are probably extractor related.
Jon

On my old Les Baer .45 I fought stove pipes since day one. Before I knew better I was convinced it was the fault of too weak of a recoil spring. One day I finally did some reading on tuning the extractor so I took it out and tightened it. I then proceeded to shoot hundreds of rounds without issue. Moral of the story, if you have stove pipe issues make sure your extractor has enough tension before messing with springs.

Larry, i run a 19lb main spring , with a 13lb recoil spring with a slide mounted ultradot.

But my ammo is about 1125 fps. Not a softball load at all. But it will shoot about 1 inch at 50 yds from the ransom rest. Jp

Just got back from shooting a new 9mm RO I built. AA Match 115 gr jhp dropped brass neatly in a pile 3 ft to my right. Aimpoint Micro slide mounted on small base at rear of slide. KKM 1:32 barrel 10# recoil spring and 19# mainspring.
Jon

Thanks for the replies guys! Right now I'm shooting a 126 Zero JHP with @ 4.3 grains of 700x behind it with a slide mounted Ultradot. I don't have a chrono so I don't know the speed. I am using a KKM 1-32 twist barrel and I'm impressed with it. Once I get it more reliable I'll be very Happy.