I just ordered my first custom barrel. I ordered a Shilen Stainless Select Match. While placing my order NSS informed me that Shilen offers for no additional cost the option to send in a dummy round which is used to customize the chamber (http://www.shilen.com/faq.html#question3)

After much searching I can't find discussions where others are talking about this and honestly have no idea if this is something I should be doing or not. I shoot mostly at 100 yards for groups but mostly just to develop loads for shooting at 1,000 yards. My primary bullet is the 175gr SMK but also want the option to shoot 178gr A-Max, and 168gr/185gr Berger Target Hybrids.

I am leaning toward just having Shilen send me whatever they typically do which I would guess should be pretty good for my purposes. While not extremely long, my selected bullets are on the long side. I imagine I will be able to reach the lands with any of these bullets.

If the recommendation is to have the chamber customized then I would ask for guidance of the seating depth on the dummy rounds I should be providing to Shilen. I have heard before that you want to seat so that the bearing surface is at least one caliber into the neck. Does this mean 1) the bearing surface should be seated into the neck (second picture) or 2) the overall length which should be seated into the neck (first picture).



As always, any advice is appreciated.