The latch shouldn't be all the way forward on the latch shelf, somewhere a bit more than 1/16" will work best, if it's all the way forward at the end of the latch travel, it may not be locked up tight. See the barrel fitting instructions in the FAQs. I'd say about .070"-.080" would be ideal. Just degrease the latch and shelf, then smoke it, or use Fred's wife's lipstick

and lock it up and see how much engagement there is, use a stone to increase it or make it even all the way across if needed, but don't over do it, or it will be loose.
Tim