.All blocks are machined from 6061 aluminum
.1/2" thick aluminum
.Holes are flat at the bottom
.Below is a short list of calibers that will fit
.38 special
.38 super
.357 sig
.357 mag
.40 s&w
.10mm auto
.22 ppc
.224 weatherby
.6mm ppc
.6.8 spc
.32-20 winchester
.7.62x39