Can the silver cases used in their 300 gr TBBC loads be reloaded?

Yes.

They are brass cases that have been nickel-plated.

Yes Gerry is right. But you might scratch around here some before you load or finish the load. I know some here do reload those cases. They are harder to size and harder cases too. While I prefer the Federal ammo in the factory loads, their brass may be somewhat down the list in re-loading preference.

I know some years ago I was going to have a custom load shop do a load for me. They wanted the once fired cases sent to them which I did. All of them were the nickeled cases from the 225 TBBC. They called and said they would not use or load those cases as they had had problems with them previously.

So check it out. Probably Ok but check it close around the neck and base.

Thank you for the quick reply.

I stopped re-loading my nickel coated cases, because I got tired of adjusting my re-sizing die between nickel and regular brass cases of the same caliber, but if you've got a lot of nickel cases then go for it.