Gary -
Not a " barrel block " so much as it is a " barrel clamp ".
I use a doubled-up plumbers repair " clamp ", carriage bolts, torque plates borrowed from "U"bolts' and nylon insert jam nuts to secure my 6mm wildcat's barrel to the channel of
an aluminum "I" beam ( oriented and used as an "H" ).
24in lb torque on the jam nuts. Clamp is relocateable. I moved it fwd from initial contact w/ the recoil lug, to tune out undesired verticle.
Fore end an buttstock are fashioned out of 5/4 composite deck board. Cheek rest is removable for barrel cleaning.
Trigger guard made by re-shaping a galvanized conduit hanger.
My " DEEP 6 " wildcat is 1,000yd capable on either varmint or target, but I've not shot is a whole bunch @ that distance.
With regards,
.357Mag