This subject is as broad as the plains and as deep as the oceans.

Gale McMillan..... In his opinion, no break in necessary... I tend to agree with this.

Other barrel manufacturers will tell of some kind of elaborate break in procedure... from wearing a blue hat and counting backwards to kissing a frog between shots...

If the shoot... swab... shoot meathod makes your heart go pitter patter then that is the thing to do...
I have used both meathods with no discernable characteristics between the two, take a veiw over to [link]http://www.6mmbr.com/index.html[/link] and see what some of the table top guys recommend.

I clean well before the opening session at the range, then depending on how events unfold, I might clean every so often, or I might clean every so many boxes of ammo shot.

I'll run a patch down the tube after the first few shots just to see how the bore is fouling... if it's bad, then we'll do the dance, till the fouling slows, if not then we just shoot.

The barrel needs time to 'smooth out' inside, and will foul accordingly... untill all the tooling marks are smoothed over you don't need to clean every few rounds.

Also... if you want to get the very last drop of fouling out of that barrel, and, I wouldn't know why, then get yourself an Outters 'Foulout'... works great.

I would stay away from using anything abrasive in your barrel... this is best left to the pros. Just because a well known shooter is 'selling' a product does not mean it is the best for your particular application.

Driftrider has summed it up pretty well....

Remember, most barrels shoot their best with 'some' fouling present.