What is the ideal degree for gas exit in a rifle barrel?

[dano1955]

Going to crown a rifle barrel and need to know what degree does gas exit?
Was told they are using this as per NASA information as opposed to a 90 degree crown.
Dan

 

[Whovian]

What?

 

[mrspeedybob]

Your question makes no sense. I suspect you are using gun-smithing jargon mixed with very bad grammar. Could you please restate the question using common English terms and correct grammar?

 

[berkeman]

Going to crown a rifle barrel and need to know what degree does gas exit?
Was told they are using this as per NASA information as opposed to a 90 degree crown.
Dan

Welcome to the PF.

There are lots of resources to help you with deciding how to crown your rifle barrel. Google turns up lots of them:

http://www.google.com/webhp?sourcei...&bav=on.2,or.r_gc.r_pw.r_qf.&biw=1234&bih=865

It would probably be more productive for you to read through the hits on that Google search list, to look at the tradeoffs for the different crown angles and styles. As the bullet leaves the end of the barrel, the gasses will expand out at a pretty steep angle. Probably not all the way to 90 degrees (for the highest velocity flow), but probably pretty close.