Keeping your throat sharp

[chino69]

After fitting a barrel for a friend, he asked that I break the barrel in, with shoot and clean . I did so cleaning after each shot.
Having a bore scope, I inspected the throat and leade with each shot. I was totally amazed how the junction of bore
and leade changed in a total of 15 shots. The apex of those 2 surfaces had already began to round.

Bob,
I own and use a borescope from the time a barrel is new, after chambering, every cleaning, etc. On a .243 A.I., there is the beginning of firecracking in as little as 80 fireforming rounds.

 

[Bob Kingsbury]

Free handing a little throat cleanup is lacking in alignment, We can easily induce some lateral force without realizing it.
Seating a barrel back .030 for those that can do it is much better