As the title says I was asked to send in a dummy round for my new barrel.As this is my first custom barrel I am not sure what all they need this for.When I was asked I assumed it was for length of the throat.I took a new piece of rem brass and loaded a 105g a-max about .10 longer than my factory barrel.So that I would have a bit more to load longer.I have not shipped it out yet I wanted to be sure that I was right about why they needed it.I would like to know if I am correct.And I dnt plan on using much if any rem brass as I will go with Luapa.