Crimping: The bullet does not have a groove for the crimp and then there is that problem with upsetting the case body/shoulder juncture when the reloader does not understand the crimp only requires a hint of effort. Ands as Lyman and Dillon said the purpose of bullet hold can be upset with the crimp meaning crimping bottle neck cases can be a bad habit.
And I am thankful I do not have any hang-ups when it comes to comparing cases, I have a discipline, I can start with 100 cases, after the cases have been fired, sized and loaded I can used the unfired cases for comparison when something goes wrong.
Goes wrong: After I have fired a case 25
times I can determine the amount of weight loss, or increase in case diameter; because I am the one that does not have datum 'hang-ups' I can measure the diameter of the case anywhere along the length of the case; that is handy when using a comparator.
I have extra barrels, take off barrels and I also have new barrels; when it comes to gages I have no reservation about cutting a barrel off when making a chamber gage. All I have to know is the amount of case head protrusion from the chamber. For example: I expect case head protrusion on a Mauser to be .110", I expect the head space clearance on the Mauser to be .005. SO? If I make a chamber gage for the Mauser I will make it with .110" clearance.
I know: Chamber gages are available and we have members that talk about owning the finest, it is not a problem for me but those chamber gages are like the Wilson case gage. I can only guess the users of these gages use their thumb nail to determine case length from the shoulder to the case head.
F. Guffey