We use an older Biach Crimper and there is a red line on the pressure gauge to indicate the stopping point. That said I've seen this pressure exceeded numerous times especially on drip legs on 650# steam systems.
As far as I know we have never had any problem crimping pigtails on our hydrogen plant using the recommend max pressure. If I remember correctly the dies that we used are designed so there is limit on travel that makes cutting a tube a very remote possibility. The moving die is also very rounded to minimize any shearing.
I don't know if I can get someone to open the tool chest and get a number for you, but I will try.
This pressure should be different with different side of pigtails and also varies with materials. I wonder if there is any way to calulate based the size and the material of the pigtails.