Tentman - a 1 or 2 die set (.318" and .315" (allowing for .001" spring back) from Lee Precision can reduce any .318", .321" or .323" bullets to .316" for you.

The do not list this service on line - but respond well to a phone call. An e-mail note might get a response as well.

They were charging $30.00 US per die that fit normal loading press 7/8 X 14 threads. A compound lever press might be necessary.