New Piston Seal Break-In?

[Trailryder42]

Hey all. Does a new piston seal need break in time to come to its potential and best sealing with the piston chamber wall?

I just replaced the stock original seal on my Pro Sport with Vorteks moly impregnated seal and lost 50 FPS muzzle velocity.

 

[davemac18]

yes they do need to brake in, they also sometimes need to be sized.