The nipple in my Musketoon looks like the first one. I have no misfires and the gun is a sub 2moa shooter. In yours' I'd be looking to the flash channel. In target guns, the orifice size on the nipple is generally pretty small. That keeps pressure within the barrel and not escaping back up the flash channel. Too large a hole and the hammer can be blown back to half or full cock. That's a sure sigh of a too large nipple orifice or way over loaded gun.
100yd group. Point of aim was left diamond point. Group size is 1.75in center to center.
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Nice group ..I am leaning to the fire channel not fully open however for a field gun I still very much like the idea of the recessed cone showing in the bottom nipple nipple which I believe might be better for hunting conditions
Bear