Subsonic, but at what temperature?
It makes a diffrence.
from one of my mentors posts on it. (RIP)
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Subsonic is a little stickier proposition. At least in my experience. For starters what is REALLY the sonic threshold? Sure, there are some "standard" answers. But reality is that in practical application they are most often wrong. At least for me, it is pretty depressing to load a batch of subs and go shoot them only to hear that unmistakable "crack" as they go supersonic over the chronograph which says they SHOULD BE subsonic. And pretty frustrating to think that I have learned from that, go make a batch with a little less powder and find it will not fully cycle the bolt.
Trust me, thats frustrating.
Soooooooooooo, this experience sent me on a quest to learn what was going on with that speed of sound thing. To that end I learned something . .
1) Altitude really doesn't have any influence with the speed of sound. Temperature does.
2) There is a really handy online calculator that does all the math for you!!!
http://www.sengpielaudio.com/calculator-speedsound.htm
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