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

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Discussion Overview

The discussion centers around the optimal angle for gas exit when crowning a rifle barrel, referencing potential insights from NASA as opposed to traditional 90-degree crowns. The scope includes practical applications in gunsmithing and the effects of different crown angles on gas expansion.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, Dan, seeks clarification on the ideal degree for gas exit when crowning a rifle barrel, mentioning a preference for information derived from NASA.
  • Another participant expresses confusion over the initial question, suggesting that it lacks clarity and proper grammar.
  • A further response reiterates Dan's question and suggests that there are numerous resources available online regarding the crowning of rifle barrels, indicating that the gas expansion likely occurs at an angle close to but not necessarily reaching 90 degrees.

Areas of Agreement / Disagreement

The discussion does not reach a consensus on the ideal angle for gas exit, with participants expressing confusion and differing levels of understanding regarding the initial question.

Contextual Notes

Participants have not fully clarified the assumptions behind the use of NASA information or the implications of different crown angles on performance. The discussion also reflects varying levels of familiarity with the terminology used in gunsmithing.

dano1955
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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
 
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What?
 
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?
 
dano1955 said:
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.
 

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