SIGforum.com    Main Page  Hop To Forum Categories  Ammunition    Can you answer the forensic ballistics questions? (Photos.)

Moderators: LDD, parabellum
Go
New
Find
Notify
Tools
Reply
  
Can you answer the forensic ballistics questions? (Photos.) Login/Join 
Freethinker
Picture of sigfreund
posted
The holes are in target paper and were caused by CCI Blazer Brass 124 grain 9mm Luger bullets fired from a SIG P320.


What are the small black spots around the holes? (No, they are not part of the paper; they were not there before the shots were fired.)

What caused the gray swirls that terminate in the holes?








I ask these questions of LE officers during range sessions. Most can figure out the answer to the spots question, but no one has gotten the gray swirls question correct.




“Most men … can seldom accept the simplest and most obvious truth if it … would oblige them to admit the falsity of conclusions … which they have woven, thread by thread, into the fabrics of their lives.”
— Leo Tolstoy
 
Posts: 40579 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Muzzle flash
aficionado
Picture of flashguy
posted Hide Post
My guess is that the gray swirls are caused by particles on the bullet flying out from centrifugal force and the rotation of the bullet (which I would say was rotating clockwise).

How close was the target? The spots could be unburned powder.

flashguy




Texan by choice, not accident of birth

When they ask me, "Paper or plastic?" I just say, "Doesn't matter to me. I am bi-sacksual."
 
Posts: 22749 | Location: Dallas, TX | Registered: May 08, 2006Reply With QuoteReport This Post
Member
posted Hide Post
I have seen those lead swirls but only when shooting rifle bullets with exposed lead on the base at 3500+ fps.

I have also seen outside lubed cast lead pistol bullets put lube splatters on the target.


armadill0
 
Posts: 31 | Location: San Antonio | Registered: April 01, 2019Reply With QuoteReport This Post
Member
Picture of 229DAK
posted Hide Post
As flashguy stated, it would help to know the distance to the target.


_________________________________________________________________________
NRA Life Member
NRA Rifle Instructor
NRA Pistol Instructor
NRA Range Safety Officer

The afternoon knows what the morning never suspected.
-- Robert Frost
 
Posts: 7354 | Location: Northern Virginia | Registered: November 04, 2005Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
posted Hide Post
Okay, another bit of information.

The shots were from about 3-4 yards.




“Most men … can seldom accept the simplest and most obvious truth if it … would oblige them to admit the falsity of conclusions … which they have woven, thread by thread, into the fabrics of their lives.”
— Leo Tolstoy
 
Posts: 40579 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Member
Picture of BlackTalonJHP
posted Hide Post
AFAIK Blazer Brass used plated pullets and is the same as Federal Champion.
Looks like the gray swirl is lead, perhaps the plating is being scored by a burr in the crown or bore.
 
Posts: 172 | Location: Texas | Registered: September 18, 2019Reply With QuoteReport This Post
Lost
Picture of kkina
posted Hide Post
I'd agree it is lead from the bullet core, outgassing from temperature and pressure. Since you're shooting FMJ, it is either coming from a breach in the jacket, or from the unplated tail of the bullet.



Accu-strut for Mini-14
"Pen & Sword as One"
 
Posts: 12683 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
posted Hide Post
Yes, the gray swirl is lead. As mentioned the Blazer Brass bullets are normally fully plated, including over the base, but I suspect a small pinhole allowed a fine stream of lead to be expelled through the plating and deposited on the target as the bullet approached. I have also seen the same phenomenon with commercially reloaded ammunition that I believe also used plated bullets.

And the black specks are unburned powder.




“Most men … can seldom accept the simplest and most obvious truth if it … would oblige them to admit the falsity of conclusions … which they have woven, thread by thread, into the fabrics of their lives.”
— Leo Tolstoy
 
Posts: 40579 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Lost
Picture of kkina
posted Hide Post
Is all Blazer ammo supplied with full plating (i.e. Total Metal Jacket or TMJ), or just their Clean-fire line? I thought their regular handgun ammo is FMJ (which means the base is not plated).



Accu-strut for Mini-14
"Pen & Sword as One"
 
Posts: 12683 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
posted Hide Post
I don’t know about any of the other Blazer Brass loads, but the 9mm 124 grain that was used for the above example has plating that covers the entire bullet. Not being sure, I pulled one to check. The box, however, does say “FMJ” rather than “TMJ” which I would expect for a plated bullet.




“Most men … can seldom accept the simplest and most obvious truth if it … would oblige them to admit the falsity of conclusions … which they have woven, thread by thread, into the fabrics of their lives.”
— Leo Tolstoy
 
Posts: 40579 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
His diet consists of black
coffee, and sarcasm.
Picture of egregore
posted Hide Post
quote:
And the black specks are unburned powder.

I shudder to think what the inside of the gun that fired them looks like.
 
Posts: 22814 | Location: Johnson City/Elizabethton, TN | Registered: April 28, 2012Reply With QuoteReport This Post
  Powered by Social Strata  
 

SIGforum.com    Main Page  Hop To Forum Categories  Ammunition    Can you answer the forensic ballistics questions? (Photos.)

© SIGforum 2019