I have two of the Burns 2oz conversion triggers for 40X/700. I used them when I shot BR in the Phoenix area a LOT of years ago. They have no safety, so they are for the bench only. Great triggers!
I second Jewell, this is what I use on my own builds, have used the Timney Calvin Elite, it is nice, but not in the same league as the Jewell. I run the HVR with top safety.