Slow-mo video of suppressors at 150,000 frames/sec

Pistolero

Well-Known Member
I bet the grains of powder were left in the barrel from a previous shot. Could not have
gotten ahead of the bullet.

You can have a LOT of fun looking at Smarter Every Day. When my wife and I drove up to
east central Wyoming to see the eclipse, it turns out that the SED team was set up about
2 miles from where we had selected. He had a friend with family who owned land there
and so that is how they chose.

I would encourage you to just randomly go thru his stuff. SMART engineer, having fun,
and very exuberant, and good at explaining tech stuff.

Here is a pic I took on that expedition.
1544316705546.jpeg

That little white dot at 8 oclock from the sun is Mercury.

Bill
 
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freebullet

Guest
Neat!

That makes me wonder if anyone has ever played with the exit baffle angle. Wondering the effects it might have.
 

RicinYakima

High Steppes of Eastern Washington
Pistoleao. I would wager that he was using a fine grain ball powder and it is blow by from windage on the lee side of the lands or in the throat. Bullets are seated deep for the semi-auto loaders and with the slow acceleration of 220+ grainers, there is lots of time for powder to blow by the bullet. IMHO, Ric
 

Pistolero

Well-Known Member
Really?! Wow, I would have never thought that the case neck would be cleared by the bullet
before the throat was closed entirely.

Ya learn something every day.

Bill
 

RicinYakima

High Steppes of Eastern Washington
One of the major issues is that the case neck, depending upon hardness, will expand to chamber dimension at about 10,000 psi or less. A long bullet can start much slower than the neck expands. Unless the bullet fits the throat and is centered, the bullet is just "floating" on a cushion of hot expanding gases pushing by. That is the primary reason match shooters are so particular about fitting the bullet to the throat, reducing the blow by (windage) to a minimum.
 

Ian

Notorious member
Neat!

That makes me wonder if anyone has ever played with the exit baffle angle. Wondering the effects it might have.

Yes, extensively.

Best results are reported from a next-to-last baffle with aperture as small as practicable/safe, and the exit aperture nearly the "next caliber up" in size. The next-to-last being the smallest aperture in the stack helps contain gas behind it and the larger exit aperture disperses gas in stages, reducing the muzzle pop and hiss effect. Dispersion slits, tap holes in the exit tunnel, and rings of dispersion holes have all been tried to varying degrees of success. One thing is clear, you do not want any parallel "tunnel" in your aperture because the Venturi effect will cause a rapid increase of gas flow, possibly creating a sonic boom pressure wave. All apertures should be internally tapered like a funnel on the back side to encourage the gas to continuously expand.

As for the supersonic bits exiting before (and concurrent with) the bullet, as Bill said that could be powder granules left in the bore from the previous shot, or even carbon chips sloughing off from the inside of the suppressor. The same effect can be observed when thumbing the cork off of a champagne bottle: The gas and liquid drops initially spray out past the cork at a much faster rate than the cork, but as the aperture opens up, the velocity of the stream slows to follow the cork. The initial gas spurt evidently has sufficient volume to propel debris out the end of the can, but interestingly is not observed with the super-sonic bullet. I'm not sure I buy the idea that whole powder granules that large are bypassing the bullet and making it all the way down the bore and out the can, but I can't prove that is NOT happening. Sub-sonic ammunition that will function a 300 BLK AR-15 will be inherently dirty, inefficient, and leave lots of trash in the bore and can.

The double-donut smoke ring is the static gas in the bore/can being compressed ahead of the bullet. If you shoot a few subsonic rounds through a suppressed AR-15, quickly change magazines, and drop the bolt on a fresh round, it will make an impressive smoke ring puff out of the muzzle.