Like the new spring used velocity tar on it.It is a very quiet spring,shot it a while ago and no spring noise ,and no i don't have a chrony,maybe later down the road.the piston seal still looked good.I'm almost tempted to do my 34 classic with a lube tune,but it still new and shooting good but a little harsh.

the accuracy? Has it improved? Can you tell? Did you do any debur to file down any rough surfaces? Did you lube everything inside with Moly paste or just put tar on the spring? BTW, I read a while back that this JM 34 kit boosts power by 1-2 FPE but I think that's the whole kit that comes with the spring guides and the piston seal.

How is the cocking effort? Probably not too different if you didn't do a debur or hone.. right?

Just put the spring in tonite i'll try the accuracy when i have daylight,i used very light moly on the piston tube and molyed the spring ends and piston guide and molyed both sides of the washer.the spring ends where very smooth so i did'nt do anything to it,it cocks real smooth and easy.