Photo of BWE weighted Uzi .22LR bolt - not mine. Said to weigh 10.7 oz.
ETA: I believe that is a steel plate on an aluminum body.
My personal experience with a D.I.Y. weighted Vector Uzi bolt of my own devise that weighs 10.8 oz. is that one can encounter feed issues with added weight. The recoil spring sometimes does not have enough force to give the bolt sufficient momentum to overcome the resistances one ammo/mag combination or another encounters during feeding. In particular, my own heavy .22 bolt would work with a few mags and hang up on the rest, and the ROF decrease from the added weight (I didn't have a meter at the time so I don't know exactly what it was), wasn't worth the hassle of keeping separate mags for this bolt or that bolt. As Thoreau said, "Simplify, simplify, simplify!"
Best of luck.
MHO, YMMV, etc.
ETA: A year ago I measured the full auto ROF using the Vector standard weight bolt and the Vector .22 recoil spring (10 coils fewer than a 9mm spring). For both CCI MiniMag and CCI SV ammos the ROF was right around 1000 RPM.
