I have two M700's one a BDL in .243, the other is a Varmit model in .222. Now the former shows a code of S for the year and the later a code of R. in other words, 1969 and 1968 respectively. Now the thing is, the .243 has 622XXXX and the .222 has 33XXXX thats like 6 million rifles different. and the .222 looks different ins certain respects, the machine work a little better, the bolt shroud is very different showing much more of the striker. the safety is a paddle shape and not a short round cylinder. thats seems alot of changes for one years difference.
Roy