Bizarre smoking bullets

[steve123]

As always, if anything astoundingly stupid or incredibly unlucky is going happen, it's going to happen to me.

Today's debicle;

I go to shoot a long range steel match and am having huge flyers, like 4 mils high and 7 mils high, dope off on easy targets, while still hitting many targets???

I'm thinking my new S&B 5-25 is screwing up and it might be???

After the match we are testing the rifle at 700Y and nailing this steel right in the middle when a friend says, hey did you see that and another friends says yeah I did, there's a puff of smoke appearing in the air about 20 yards out like if the bullet was blowing up in mid air. He tells me to watch as he shoots the rifle and sure enough, poof, a white cloud of smoke appears and gets carried away by the wind. !@#$%^&

To my knowledge this has never happened before with this rifle and load.

Got any answers guys?

 

[wburke2010]

It would help to know the load and details for it.

Walter

 

[Big Dog Steel]

It sounds like you are tearing the jackets off...A long while back I ran into this with a 7mmRM and 180VLD's. I guess I was pushing them too hard and they were tearing themselves apart. A few would shoot ok, then poof... What are the rifle specs and what bullet?

 

[ksthomas]

You're losing jacket integrity there. The jackets are suffering some degree of failure, and the puff you're seeing is the molten lead outgassing through that void. Berger spent some major money to have this tested at MIT a few years back, and actually captured many bullet failures in flight, on camera. They also did quite a bit using thermal imaging, allowing them to determine the temperatures of various points on the bullet. The conclusion was that the jackets wre transfering just enough heat to some areas of the core to create a thin boundary layer of molten metal, which could then leak from any small pinhole voids in the jacket material. This was what caused the division of their "Match" and "Hunting" lines; a slightly thicker jacket design to preclude this from happening. I've seen this occur many times, with a variety of different makes and brands of bullets. Given the right (or wrong, depending on your point of view) combination of circumstances, it's fairly repeatable. There's a variety of things that go into this, including jacket thickness, core alloy, bore and throat condition and no doubt several others. Interesting phenomenon, though.

 

[zuke]

Also called blue streak

 

[steve123]

It was in my 6x47L with 115 DTACS going 3000 fps.

 

[steve123]

You're losing jacket integrity there. The jackets are suffering some degree of failure, and the puff you're seeing is the molten lead outgassing through that void. Berger spent some major money to have this tested at MIT a few years back, and actually captured many bullet failures in flight, on camera. They also did quite a bit using thermal imaging, allowing them to determine the temperatures of various points on the bullet. The conclusion was that the jackets wre transfering just enough heat to some areas of the core to create a thin boundary layer of molten metal, which could then leak from any small pinhole voids in the jacket material. This was what caused the division of their "Match" and "Hunting" lines; a slightly thicker jacket design to preclude this from happening. I've seen this occur many times, with a variety of different makes and brands of bullets. Given the right (or wrong, depending on your point of view) combination of circumstances, it's fairly repeatable. There's a variety of things that go into this, including jacket thickness, core alloy, bore and throat condition and no doubt several others. Interesting phenomenon, though.

That explanation makes sence.

When I first got the rifle the load I worked up was at 3000 fps with same brand bullets. As time went by my powder scale started wacking out .2-3 grains, then I borrowed a friends scale and his threw lighter charges, went through a couple 8 lb jugs of powder...anyways the load ended up at 2925 fps and was working fine but slower than I wanted.

Got a new jug of powder, Scott Parker tuned scale, new box of bullets, refined the charge and seating depth and was shooting some .3" groups. Now this.

The Barrel is a Schneider 5P, 7.5 twist, Melonited and has 2300 rounds down it.

Thanks Guys!

 

[Unsichtbar]

Seen this happen several times people shooting a 1000 yds bullets vaporize on way to target, smoke contrail. I addition bullet holes with a little smoke trail over the bullet hole. Once I was pulling at 1000 yds no bullet impact in the berm, they kept yelling for a pull, bullets made it to target but blew up after hitting the paper, no berm impact. Most of the time 6mm or 6.5mm bullets at hyper speeds.

 

[ksthomas]

Not always really high speed projectiles, either. Had a guy who sent in some targets while I was with Sierra, shot with their 140 SMKs at around 2500 fps from a 6.5x55 Swede. The targets showed halfway decent targets shot at 100 yards or so. The interesting thing was the bullet holes. Heavy card target stock that shoed not only very heavy lead smears in a "comet tail" type pattern, sort of like a comma coming off the bullet hole itself. I mention that the target was heavy stock, because the lead particles actually cut the paper completely through, througout most of the lenth of the lead smear. Interesting stuff, and very clear evidence that lead was outgassing in large enough quantities to actually carry some measure of energy with it.

 

[judgedelta]

I blew up some soft-nose .223's in a Savage Mod. 12 w/ 26" barrel, using what was supposed to be a reasonable load of VV-140. Couldn't figure where the bullets were going since I could put 3 or 4 touching then a clean miss. Finally saw the smoke and could find peck marks in the target...