The technical stuff:

Durocast™ is a registered
Trade Mark for WEXCO' s best bore protection for plasticating barrels. This bore
inlay features solid (i.e. not hollow), spherical tungsten carbide combined with
a chromium-boron-nickel matrix.
The solid spherical tungsten carbide provides outstanding primary wear
resistance. It yields a micro hardness in the barrel bore of over DPH 4000 (a hardness range too hard to measure with the standard Rockwell “C” scale).
The chromium boride, along with the high
chrome content, further enhances wear
and corrosion resistance.
The high density of spherical carbides makes this WEXCO
lining material an
excellent choice for longest-lasting performance.
The “core” of our limited 5-year warranty:
WEXCOs Durocast™ bimetallic cylinders are warranted
against excessive wear for a period of 5 years from date sold. WEXCO
guarantees that Durocast™ cylinders will not wear more than .010”
(total) on the bore diameter.
(for an excerpt of our DurocastTM
wear warranty, see the link
below)