Kimio, I am a reloader, I form cases. I understand the "ALL YOU GOTTA DO" responses. I was visiting a manufacturer of reloading equipment, while visiting the subject of case forming came up, the tech type took off in automatic. He started with "ALL YOU GOTTA DO IS etc..". I stopped him before he had a lot of time invested in his response, then I asked him if he had ever formed a case. He said "No".
I do not have a reason not to have the correct equipment, I have formed enough 7.7 Japanese cases to pay for a forming die many times over. I do not have a 7.7 Japanese forming/trim die. I have a 308 W forming die, it is my favorite because it is short and the body is larger in diameter than other cases. A shooter west of Ft. Worth had the same question a few years ago, He received the same answers: "All you gotta do is etc..".
I formed close to 80 cases in different length from minimum length, go-gage length, no go-gage length and field reject length. The minimum length cases chambered, the go-gage length cases chambered with slight felt resistance to bolt closing. The go go-gage length cases would not allow the bolt to close and the field reject length cases required sizing and trimming.
When forming cases I consider the chamber can be long as in longer than a go-gage length gage. When forming with a short forming die I adjust the die off the shell holder with a feeler gage added to square stock. I determine the difference in length between the 308 W and 7.7 Japanese case to determine the gap between the top of the shell holder and bottom of the die. I sent him 4 different length cases because part of his question about his chamber was "How to determine head space of the chamber?" His chamber was go-gage length. By the time I met him at the Dallas market Hall Gun show he had fired all of the cases.
F. Guffey