Bullet jacket material has been carefully developed over the years to give minimum wear to barrels, and it is real good in that respect. So, the many breakin procedures you read about are an awful lot of work with very little results.
Lapping with the LBT lap kit will do a far better job than any jacketed bullet breakin, and do it quickly if the barrel is a real good one. If it's a standard production barrel, it will break it in and also turn it into a premium target grade barrel.
There is no way to tell you how many shots except to tell you to use our push through slugs and lap till they tell you the barrel is perfect. That could be in as few as 15 shots, and up to 100 if it's a rough barrel. You'll never regret taking the project on.
What breakin processes are trying to do is minimize jacket fouling, and lapping does it fastest and best. Partly because it very slightly increases the diameter of the throat and bore close to the chamber. So in addition to slowing the fouling buildup, this also gives more room for jacket fouling buildup before the first few inches if rifling becomes smaller than the rest of the barrel, which is the degree of fouling which causes jacketed accuracy to fall off.
