Went to tune a guys trigger for him today, and it was definitely not one I'd seen before.

There was a set screw for the safety and over travel, but they weren't accessible with the trigger in the group. The sear engagement was at the end of the bar instead of on a ledge, and it had a thick screw head there to set depth. The wider the screw head, the less engagement. Turning the screw didnt look like it'd make any difference. You'd have to pull the trigger out to do that anyways, as the sear would be in the way of accessing the screw. This is from a early 70's left handed 243. We think its early 70's at least.