556 ammo question

Um. At the muzzle. From that point on, it's losing velocity. Perhaps what you want to know is how much velocity does the bullet retain over distance? If so, the average muzzle velocity is just under 3200 fps. The average at 100 yds is just under 2800. The average at 500 yds is just over 1500, so still supersonic at that distance. Does this help?
 
I have some ballistic panels. So I give a steel guy in the jobsite a piece to play with. The panels are rated at a Lecel 2. These should stop a 357 mags. The next day he brought back a video of him shooting it with a AR. It didn't penetrate the panel. So I asked him how far away he was when he shooting it. He said about 25ft. Im thinking the 556 should have went through it hauling ass but I'm thinking that the projectile didn't have time to come up to speed.
 
I was thinking bullet equals little rocket then it all set in. I've never really put any thought to it but now I understand and understand why a longer barrels produces more velocity.

Just ignore me now
 
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Majicmike said:
I was thinking bullet equals little rocket then it all set in. I've never really put any thought to it but now I understand and understand why a longer barrels produces more velocity.

Just ignore me now
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A bullet will gain velocity in a longer barrel only as long as the powder is burning. After that, the round will start losing velocity even in the barrel. It's all about the propellant. Otherwise, the bullet just lies there. :)
 
How did he mount it? Are they rated based on hanging free or rigidly held?
 
JimB said:
How did he mount it? Are they rated based on hanging free or rigidly held?
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This ^.

If they're rated for .357 while stationary (vest on a 200lb man, ballistic door insert in 2000lb car) but then you free hang them and shoot them with a rifle, yeah the rifle may not penetrate. Doesn't mean the same will happen when you take the swing out of the target.
 
JT said:
A bullet will gain velocity in a longer barrel only as long as the powder is burning. After that, the round will start losing velocity even in the barrel. It's all about the propellant. Otherwise, the bullet just lies there. :)
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Yep. You can actually get less velocity in a longer barrel with some 9mm rounds (think 147 gr ammo in a 16" carbine barrel). Faster burning powder optimized for shorter barrels.

Conversely, magnum pistol calibers (.357, .41, .44, hot loaded .45 Colt) tend to have significantly higher velocities in a carbine vs. a pistol because of slower burning powder.
 
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JT said:
A bullet will gain velocity in a longer barrel only as long as the powder is burning. After that, the round will start losing velocity even in the barrel. It's all about the propellant. Otherwise, the bullet just lies there. :)
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That's what hit me,, It was the only times I've ever cared to think about it:cool:
 
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Majicmike said:
I just thought about it, the muzzle brake makes sense.
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Yeah, that must have been it. Taking that sucker off is like a NASCAR pit crew removing restrictor plates, it'll go through anything.

:D

I wish I were closer, I'd take you up on that offer.
 
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