I had a problem like that with a 230gr RN which actually has a very slight flat nose. Finally realized that seating to a "normal" C.O.L. left it a touch too long. None of them would go into battery. Pushing them in another 0.002" solved the problem.

Keep in mind, though, that seating a bit deeper may reduce case volume and therefore, increase pressures slightly. Stay conscious of that and cautious, too.

--Wag--