Your Western Field model 768 was made by mossberg for the Mongomery Wards company(Western Field).The mossberg model 800A is the same rifle as yours.
I belive it was mossberg? DEFINITELY!
Neither Revelation nor Western Field made firearms. The first is a brand name retailed by Western Auto and the second by Montgomery Ward. The Revelation 220 is a Mossberg 800 and the 225 a Savage 340.
100-300 or so
This is the same as the Mossberg 800 and was made in the late 1960's into about 1980. Value ranges from $200-$300.
An air rifle could be made in that calibre. Benjamin made a model 242 and 247 in .177 and .22 calber from 1968-92 but not a model 243.
1955, Winchester Model 70.
.243 was made in a variety of Browning Rifle models. There are too many to list. Perhaps you could provide a model and we could tell you if it "wasn't" chambered in .243
Don't know about the 243 carbine but the serial numbers for the model 100 go up to 263170 on the site I use to check dates. That number sounds about right but the model 100 was made in a .308 and a .243 with the .308 being the majority.
1976
100-300 or so
Can't answer without knowing who made it.
It is a Winchester Model 70. Great rifles.