How many shots would you say it takes to break in a new barrel, and how is the best way to do it correct?

Also, when a barrel is broke in correctly, will the velocity increase or decrease?

Scratch

I used 50 shots in my 300 Win and it work out very well

There are no specific number of rounds that will do it, per se.

I have had some barrels, be broken in after 5 shots,and had one that took 95.

I usually give a barrel up to 100 rounds, and if it does not perform by then, it is history.

Breaking in, is like politics, everybody has a different opinion.

Usually, I give the barrel 50 to 100 strokes of Flitz on a patch wrapped around a brush.
(changing patches every 5-10 stokes)

This is before I ever fire a shot.

Then fire 1 and brush and clean, then fire 2, brush and clean, fire 3 etc up to 20 rounds.

Then clean every 20 rounds.

Ditto Terry - In a factory, non-lapped tube it can take 50 or more rounds until it settles down and becomes easier to clean. Premium bores which are hand lapped or are otherwise finished will break-in within 10 rounds or so.

The best thing is to clean the bore often during the first 30 to 50 rounds as Terry described. The one shot clean method is widely accepted as the normal procedure. I have bore scoped one factory bore during the break-in process. You can visibly see a substantial difference in the roughness of the bore after 50 rounds.

I start a new factory bore out with 20 passes of JB bore paste to remove the crud from the bore. The first 15 rounds are one shot and clean. If after 20 rounds the bore is still fouling considerably, I will go back to the JB.

To clean between shots I use a few patches of Butch�s Bore Shine to remove all the powder fouling and most of the copper fouling. A clean patch or two to remove the solvent, and a very, very light patch of Butch�s gun oil before the next shot. It does take a little time, but I don�t scrub the bore to death either.

The Butch�s site has a very good section on cleaning and breaking-in a bore - http://www.bbsindustries.com/technical.html

Answer to original question; Never ifit an ER Shaw barrel. (ahere we go again)

Last October, November, I broke in a new 300 WSM with a blue barrel. I did around 20 rounds cleaning after each, then stepped up to 3 rounds between cleaning. I can't remember how many rounds I did. I did writing the all in a notebook. An odd thing happned; the rifle started shooting all three rounds into a tight group out of a cold, clean barrel. This particular rife has done the every time from the first three round groups I fired. I don't know if breaking in did it, but on Monday I brought home a new 270 WSM in stainless, and this one will get the same treatment.

I did do one thing. I settled on a load for breakin and used it throughout so I could guage the accuracy of the rifle with consistent loads. It settled down to smaller groups as I proceeded.

I wouldn't swear that breaking in made the 300 short that way, but I can't say it didn't. It was the first rifle I actually treated to a breakin period; I will do all of my new ones in the future.