Dave H.
From the benchrest crowd....
Tuesday, January 30, 2018, 13:04

I can't recall the last time I saw a McMillan tube at a stool shoot, but nonetheless Shilen is a popular brand (along with Hart). You won't find a Douglas barrel among serious shooters. From the Shilen website:

How should I break-in my new Shilen barrel?

Break-in procedures are as diverse as cleaning techniques. Shilen, Inc. introduced a break-in procedure mostly because customers seemed to think that we should have one. By and large, we don't think breaking-in a new barrel is a big deal. All our stainless steel barrels have been hand lapped as part of their production, as well as any chrome moly barrel we install. Hand lapping a barrel polishes the interior of the barrel and eliminates sharp edges or burrs that could cause jacket deformity. This, in fact, is what you are doing when you break-in a new barrel through firing and cleaning.
Here is our standard recommendation: Clean after each shot for the first 5 shots. The remainder of the break-in is to clean every 5 shots for the next 50 shots. During this time, don't just shoot bullets down the barrel during this 50 shot procedure. This is a great time to begin load development. Zero the scope over the first 5 shots, and start shooting for accuracy with 5-shot groups for the next 50 shots. Same thing applies to fire forming cases for improved or wildcat cartridges. Just firing rounds down a barrel to form brass without any regard to their accuracy is a mistake. It is a waste of time and barrel life.