One more comment and the choice is up to the individual whether to break in or not.
In my opinion, The barrel is the heart of the accuracy potential so "Taking care of it" is paramount.
When braking in (Or not) after each shot all types of fouling is laid down in the barrel. Some is copper (Not to bad but it will prevent the barrel from breaking in uniformly).
The next Is Carbon. (Very bad and abrasive) and if it is left in the barrel and fired, the bullet will pick some of it up and run it down the barrel. The rougher the barrel finish, the more carbon it will hold and the more the bullet will pick up. One of the major reasons for lapping a barrel is to minimize the fouling from shot to shot. A good break in also does the same thing. when breaking in a CUSTOM HAND LAPPED BARREL it gets better and better as brake in continues and fouls less and less.
Many years ago I did not realize how much carbon is left in the barrel after one shot so I did a simple test. I cleaned until the barrel was pristine and fired one shot. Then I slowly pushed a dry patch down the bore and when the patch exited the muzzle I was surprised at the amount of residue from just one shot. (The next bullet pushes it's way through all of this and does damage
to the bore of the barrel). So the less a barrel fouls, the less carbon is pushed through the barrel
while firing. Try this with your rifle and you will see how much is pushed through your expensive barrel after only one shot. (Looking down the barrel with a bore light it may look great, but the dry patch will tell you the real story. Also Some powders are worse than others.
I know it sounds Anal, but when I am hunting and have the time, I pull a Bore snake through the bore just to sweep the powder fouling from the bore so the next shot is at least free of the lose stuff.
In my experience, Barrel life and accuracy are extended if a barrel is well maintained after break in
so brake in (Yes it is time consuming)is time well spent in my opinion.
So is break in necessary ? Everyone decides for them selves. After spending lots of time and money to own a rifle that will out shoot me I will do everything I can to make it last and hold it's accuracy as long as possible.
J E CUSTOM