I just got my Davenport P17 custom 416 Rigby from Champlin's today. It's really sweet. But...
I pulled the trigger 16 times with Hornady factory loads (no handloads for test firing on approval.) One ragged hole at 100 yards with three rounds. Unfortunately, with 16 shots, only 14 discharges. The primers looked pretty well dented, and one of the two rounds refused to fire on a second attempt.
George is great to work with. I'm sending rifle and ammo back to Champlin's for inspection. He feels that there may be an issue with factory ammo dimension (read headspace) with these rounds.
This is not reassuring in a dangerous game rifle. Has anyone had issues like this? I plan to load my own, but a DGR needs to shoot factory ammo reliably.

Have had problems like this with a VZ.24 and a Savage. Both rifles required either a new firing pin spring and/or more firing pin protrusion.

After a headspace check, I made up some sized and primed cases and then fiddled until they worked all of the time.

No problems since fixing the problem.