What parts of the gun do you think leave class or individual characteristics on the cartridges and bullets?
Answer: The hammer, the inside of the muzzel (or bore), the ejector, and the breechblock
Together they’re called a cartridge.
This is the bullet . It’s the actual projectile that comes out the loud end of the gun. This is the casing , or shell . It encloses the whole shebang. This is the powder . This is the stuff that combusts and propels the bullet out of the loud end of the gun. This is the rim . This is what the extractor grabs to eject spent casings. This is the primer . This is what the firing pin hits, which then ignites the gunpowder, which then propels the bullet out of the loud end of the gun.
You are about to shoot Homer Simpson. Notice the lands and grooves that are about to spin you out of the barrel greatly increasing your accuracy.
This is what you would look like after you’ve been shot out of the barrel of a gun.
Caliber of a weapon is measured between opposite lands. Expressed in hundredths of an inch or in mm.
Caliber of a weapon is measured between opposite lands. Expressed in hundredths of an inch or in mm.
Caliber of a weapon is measured between opposite lands. Expressed in hundredths of an inch or in mm.
Caliber of a weapon is measured between opposite lands. Expressed in hundredths of an inch or in mm.
Striations are the unique pattern of toolmark scratches left on the lands and grooves by the gun manufacturing process. No two guns have the same striations. Striations also change over time as the gun is used. The changes are not so dramatic between firings that positive identifications cannot be made. Just as with fingerprints there is no necessary number of match points for an ID to be made.
Often your bullets are not in the best shape.
No examplars for you!
Mr. Chenney’s “friend.”
Shotguns have smooth bores.
What similarity do you see between a shotgun cartridge and a bullet cartridge?
Shotgun cartridges are packages of “shot” or lots of bb’s. Shotguns come in gauges, not caliber.
This is shot.
Shot comes in different sizes.
If a shotgun cartridge contains only a single shot, it’s called a slug. This is a slug. Ouch.
Slugs also come in lots of different sizes.
Here’s what a shotgun cartridge looks like as it leaves the barrel. The spread of shotgun pellets expands approximately 1 inch for every yard travelled from the barrel.
Since 1999: NIBIN obtained over 2 million records NIBIN partners have confirmed more than 40,000 NIBIN hits (matches) NYPD has become the most successful user of NIBIN with 2,500 plus hits
Since 1999: NIBIN obtained over 2 million records NIBIN partners have confirmed more than 40,000 NIBIN hits (matches) NYPD has become the most successful user of NIBIN with 2,500 plus hits
When a gun goes off, a lot more leaves the barrel than just the bullet.
You can look at the pattern of the gunshot residue on the target to make a guess about the distance of the shooter from the target.
Characteristics: A hole Visible ring around the hole, aka bullet wipe Burned or singed material around the bullet hole Sometimes the hole is accompanied by a stellate, or star shaped tear pattern
This will damage the striations on the inside of the barrel or dislodge dirt and material that may have contributed to individual characteristics on your evidence bullets.
Go for it! The bumpy part of a gun handle doesn’t take prints well. You won’t be disturbing any usable latents by handling the gun there.
Uh, yes, please! I think the lab technicians will appreciate if you don’t send them loaded ammo in the mail.
Yup. You need to make sure the gun is safe before you collect it as evidence, but you should also record everything about the gun that you can before you send it off.
Nope. Mark the bullet either on the nose or the base to avoid damaging those precious striations again.