Is all fire cracking bad

[buster2765]

I have a Savage FCP 338 lapua That will not shoot groups consistently under 1.5 inches at 100yds (occasionally sub moa). This is my 3rd savage 338 lapua and have never had an issue being sub moa out past 1000 yds Until the round count gets to 1200 to 1500. AS I bought this one on another forum used I do not have a round count to blame it on. I recently bought a Lyman Bore cam and can see fire cracking .25 inches into the lands. The edges of the land appear good in the rest of the barrel (to my untrained eye) compare to a new savage barrel I have.

 

[milo-2]

You did not say how far it extends into the barrel, just that it starts 1/4" in, where it usually does. To answer your question if all fire cracking is bad, well, nothing good can come from it really.
You mention it does not shoot like others you've owned, and now that you have a borescope and can see discrepancies, I doubt you will ever trust the barrel.
This is my opinion, you can buy the same brand of barrels repeatedly, but sooner or later you will get one that is softer or harder steel, not sure which, that will crack like that prematurely, when others have not. I've shot Hawk Hill exclusively for 4 yrs, most hold up, but I have a Dasher barrel that looked worse than yours in 600 rds. It's at 1200 now, looking worse but still hammering, so they can still shoot, just a time bomb though.
All barrels eventually fire crack, you are pushing 85+ grains of powder, a lot of heat in a small area, the faster the firing rate, worse it gets.

 

[buster2765]

1/4 in. is an est. of total length of fire cracking starting where the rifling begins. I do have a new unfired take off Savage barrel sitting on the shelf & will be doing the swap tonight.

 

[KyCarl]

I really don't see how it can be avoided? It seems like some fire cracking is going to happen..No matter what? I have a brand new MPA 338BA that I'm about to start shooting
(when it's not 95 outside) and I'm going to watch it closely!

 

[sable tireur]

As I've stated before, the only way to avoid wear in your barrel is to not shoot it.

From the first shot forward, your barrel will show some form of wear based on the fact that you are launching a bullet down the bore which wears the lands and the super heated plasma from the ignited powder acting like a blow torch on the same area in front of the chamber all the time, melting the lands and grooves area a little at a time. As the hot steel cools, the fire cracking forms. The fire cracking will eventually collect copper from the bullets and carbon from the burning powder. Both are harmful to accuracy and consistency.

 

[squeezenhope]

As I've stated before, the only way to avoid wear in your barrel is to not shoot it.

From the first shot forward, your barrel will show some form of wear based on the fact that you are launching a bullet down the bore which wears the lands and the super heated plasma from the ignited powder acting like a blow torch on the same area in front of the chamber all the time, melting the lands and grooves area a little at a time. As the hot steel cools, the fire cracking forms. The fire cracking will eventually collect copper from the bullets and carbon from the burning powder. Both are harmful to accuracy and consistency.

 

[squeezenhope]

I suspect every barrel is different, but at least with some barrels you can have considerable cracking before accuracy starts to suffer. Just how much is anybody's
guess. My two most accurate hunting rifles will hold under 1/2 MOA and both have noticeable cracking. I have not measured how far it extends up the bore. Don't really care, when the accuracy goes it will be time to address the problem.