Is it any good for 416 Rigby or is it better to stay with Norma?

Can't directly address the Rigby, but I would stay with Norma for it.

My experience with Bell (Mast) brass is NOT good. They also make the stuff for Lazzeroni which is pure junk even with the tighter quality controls. If you want chapter and verse of my Lazz experiences I'll be happy to give it to you.

I was first exposed to their brass in 404 Jeffery as well as their basic. Unbelievable the variances in the wall thickness. Roughest brass I've ever seen on the inside. I used the Jeffery as the parent case for some Jamison ammo. I NEVER got more than 5 reloads out of the brass before it started splitting, and this with annealing in various different stages to try to prevent this.

Admittedly this has been over a year for the Lazz, and several for the Jeffery so their quality could have risen a bit. Nevertheless, if you gave it to me I wouldn't use it. Stick with Norma. I've had good luck with it in my Rigby.

I tried the BELL 470 brass, and I had a problem with it. Even after full length sizing it would not chamber in my rifle. Apparently the case just above the rim was not the correct tolerances, or maybe the rim thickness/diameter was also not right. Anyhow, I sent it back, and I only use Norma brass for my 470 loading.