Questions concerning quality control on new Model 12 LRPV.

[Whynot]

A crown is just there to protect the muzzle end of the rifling from being 'dinged'..

As I understand it- that is one of the purposes of a crown. The other is that as the bullet leaves the barrel and the gasses are escaping that you want a smooth consistent escape path for the gas so they do not put an unbalanced force on the bullet. And that the 11 degree crown was actually the result of a lot of science and testing...... but for 1 specific bullet design. With that specific bullet they decided that 11 degrees was the optimum for letting gas escape without impacting the bullet...... but then it just became the go to.

[South Prairie jim]

As I understand it- that is one of the purposes of a crown. The other is that as the bullet leaves the barrel and the gasses are escaping that you want a smooth consistent escape path for the gas so they do not put an unbalanced force on the bullet. And that the 11 degree crown was actually the result of a lot of science and testing...... but for 1 specific bullet design. With that specific bullet they decided that 11 degrees was the optimum for letting gas escape without impacting the bullet...... but then it just became the go to.

I’ve shot both and I can tell you with certainty that 11degree or step/ Varmint crown will make absolutely zero difference on the target out to 1000 yards.
I would more concerned as to which twist rate the barrel came with, hopefully 1-8..and not the 1-12

[sharpshooter]

There is no science behind an 11 degree crown, or any other crown for that matter. A crown is a crown, as long as it is cut perpendicular to the bore. As for a specific bullet type, that has never been proven.
The fact is, this no more than a trend that stuck. The 11 degree crown came about when a gunsmith cut a crown on a bench rest barrel without knowing that the compound was not square. When the cut was finished, he thought it looked cool, and just left it that way. So, naturally when he goes to the next match he gets questions. After he won the match, he gets more questions so he made up a bullshit story, and now everybody copies him.
The guy that told me that story was Fred Sinclair.

[Dave Hoback]

Is there an echo in here, LOL!

I’m sure Sinclair even made that story up! LOL! I can list half a doze articles or more with the origins of the 11 degree crown. While it is probably along those lines; someone, somewhere used it in a winning rifle & people took notice, the FACT IS nobody truly knows where or exactly when it started.,,

[South Prairie jim]

You guys would know more about the origins than I would, I just shoot the targets that are assigned to me and report back.

[Whynot]

There is no science behind an 11 degree crown, or any other crown for that matter. A crown is a crown, as long as it is cut perpendicular to the bore. As for a specific bullet type, that has never been proven.
The fact is, this no more than a trend that stuck. The 11 degree crown came about when a gunsmith cut a crown on a bench rest barrel without knowing that the compound was not square. When the cut was finished, he thought it looked cool, and just left it that way. So, naturally when he goes to the next match he gets questions. After he won the match, he gets more questions so he made up a bullshit story, and now everybody copies him.
The guy that told me that story was Fred Sinclair.

So it doesn't matter to me one way or the other because also have barrels with different styles of crowns that shoot great. With the evidence that I've seen (high speed photographs of the gas escaping a barrel at roughly 11 degrees) and the stories told to me- I still believe it was based on theories and tests. That doesn't mean they came up with the right answer- because as stated lots of ways work.

I do call BS on the story you posted though..... I'm not a great machinist- but even with my limited skill can easily see if cutting 11 degrees off.... so someone skilled enough to build bench rest winning rifles should easily spot it as soon as it started.

But if there's no advantage to it then I don't get why it has stuck around. There's easier crowns to do- and it doesn't offer as much protection as other ways- so it may as well go away.

[GrenGuy]

I have cut barrels in My garage and crowned them using hand tools. The barrel shot less than MOA when I started and was better yet when I finished. Probably, because the shorter Barrel was a little stiffer? There are methods on the i net for DYS crowns. There are examples on line where barrels were cut off with an abrasive chop saw, to perform velocity test, and it did not deter from accuracy.

All good information, but drifting away from the original thread.