After a marathon of beveling the mouth of new cases for the last 2 days I have some questions. I have for year now trimmed or beveled the inside and outside of the new and used cases because that what I was taught to do.
I understand beveling the inside so it does not shave the copper jacket of the bullet and give a smoother seat to the bullet as your seating it. but I do not know what is gained by beveling the outside wall of the mouth of the case. It looks to me that cartridge manufacturer do not do either possibly to reduce cost? So is it necessary to do a outside bevel on you cases and what is gained if you do?
Great question, and admittedly, I have never really thought much about this, so there may be something I’m missing too.
It seems to me that the main purpose of the outside bevel is to improve feeding. I’ve seen a number of guns where that mouth on the cartridge case where it meets the bullet can be a sticking spot in the action or magazine.
The other purpose I see is that if you’ve trimmed, you could have a burr on the outside of the case mouth, which could cause issues in the chamber.
Jim is right here. It is all about feeding and fitting into the chamber properly. You could get away without doing it on a thousand cartridges but then have one hang up when you need it the most. Semiautomatics are much more susceptible to this but it is possible for other actions to have problems as well. In my opinion it’s a must do step in the process.