Before you continue, reread AGCurry's post a few times and commit it to memory because it's the perfect answer to probably 1/4 of the questions that get asked in this forum.
"Metal vocals" could mean any number of things. Here is a quick and dirty list to help if you're not actually interested enough or able to put in the time and resources involved with an afternoon of serious mic testing.
If your metal vocals are Dream Theater style metal vocals, get any large diaphragm condenser. Put the pop filter 1' away.
If your metal vocals are Metallica style metal vocals, get a Sennheiser MD421. Put the pop filter 2" away.
If your metal vocals are Cookie Monster style metal vocals, get a Shure SM57. Don't bother with a pop filter, you need any kind of dynamics out of the performance that you can get.