Quick question, almost got my baby finished.

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In a real rifle, parts (mostly barrels) will have a break-in period where the metal settles. As we all know, metal becomes soft when heated. When you fire a brand new gun that is the first time the barrel has experienced intense heat since it was made so it undergoes some degree of transformation from break-in.

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This is a common misconception with sniper rifles, which we professionals refer to as "voodoo precision". In "voodoo precision" people are using their high-end weapon systems and following steps without knowing exactly why it's working. As far as they know, it's all magic...

People will tell you about so many rounds of break-in before a weapon system is really hitting it's sweet spot. Ever hear of a "break-in period" for a Kalashnikov or Glock? For guns like $2000+ 1911's it usually because the tolerances are very tight and you need a couple thousand rounds of weapon cycling for the weapon to settle its part in consistent harmony. But there aren't that many moving parts for your classic bolt action.

When it comes to sniper rifles, the break-in period is caused by the same phenomenon that occurs with your cold bore shot. In the case of a "cold bore", when you fire the first round it will impact different from where subsequent shots group. Clean the weapon exactly the same way, every time, and you can properly anticipate where the initial round will print.

It's because of both cleaning residue left in the barrel and copper fouling from the bullet traveling the lands and grooves. This is why you'll more and more see the cold bore shot referred to as CCB, for "Clean/Cold Bore".

The difference is: If I shoot 10 groups within 20 minutes, then leave the weapon in that spot until the same time the next day (without cleaning and all things like temperature and humidity being equal), then shoot again the next day, it will print the groups in the same spot without an initial CCB shot.

If my high-end, high-dollar sniper rifle requires a break-in period, I'm going to be pissed. That's what I'm supposed to be paying for. If you made a barrel that requires a coat of copper to fill in imperfections, then you shouldn't be charging so much for your gun.

However, depending on the prior use of your weapon and how it's been cleaned, it may require accurate documentation and a consistent cleaning procedure to know your CCB. After so much fouling and improper cleaning, cleaning out all the copper may actually cause accuracy to suffer.