What kind of rail is on the Remington tac1 airsoft gun?
The rail is a copy which seeks to emulate the MIL-STD-1913 (also
known as 'Picatinny') rail system common to NATO and
Western-aligned military weapons. However, it may not be
manufactured to the specified dimensions of the MIL-STD-1913
system, but rather, the Weaver rail system.
There are three common types of these rail systems:
MIL-STD-1913/Picatinny (which is common for military and law
enforcement applications), the Weaver rail (which is commonly used
for mounting scopes and optics on commercial hunting rifles), and
the Diemaco rail (a variation of the Weaver rail first used on the
Canadian variation of the M16 rifle).
The difference between the two is that the Weaver rail has a
slot width of 0.180 inches, with no specifications for the slot
centers. The MIL-STD-1913 rail has a slot width of 0.206 inches,
and all the slot centers are spaced at 0.394 inches.
To determine which of these specifications the rail system is
based on would require measurement with a set of calipers. If you
are unable to do this yourself, any gunsmith or tradesmith in any
occupation requiring the use of calipers should be able to do
this.