Why not Tungsten match rounds for 70% greater ballistic coefficient?

[Unclenick]

Corbin sold Tungsten powder for bullet cores for a long time, but I see they say it is now discontinued due to high market prices. When Precision Shooting was still publishing, someone was making Tungsten core bullets and published some positive things about what they could make them do, but I don't think they ever took off. The idea was, as suggested earlier, you could have more powder space for your bullet weight. The idea was extra velocity and the extra mass would make up for the shorter shape if you did the shorter shape right. The extra mass and shorter shape would let you use a slower rifling pitch as the greater mass doesn't need to spin as fast to achieve stability. This lets you drive it still faster without disintegrating from spin and it then tends to have less wobble in flight.

Too expensive, at several dollars a bullet.

 

[briandg]

Im amazed at the price of tungsten these days. Almost ten bucks to purchas scrap, and scrap isn't going to b the price of useable powder, that should run almost twice that price, and any machined materials of any sort will probably run at least $100 a pound, whether it's rod, or any simple bulk product.

I remember reading up on the price of carbide scrap years ago and it wasn't even half of that price. There must have been some political change in the price, it is mined in south america and russia, IIRC. I do know that machine shops have never dumped their carbide tools, and they will pop the inserts off of their saw blades if there are many blades worn out. It doesn't take a whole lot of carbide equipment or tools to reach a pound.

a cubic inch of tungsten weighs almost a half pound. That's even denser than my brother in law.

 

[Unclenick]

It's funny. You'd think with the incandescent light bulb dying out, there would be less demand for tungsten, not more. Perhaps it is tooling demand coupled with the tungsten carbide wedding ring fashion that has taken the trend the other way?

 

[emcon5]

Corbin sold Tungsten powder for bullet cores for a long time

I remember that, for a while there it was touted as "The next big thing®" for Service Rifle shooters using the AR15, because the Tungsten cores you could get close to the BCs of the 80 grain Sierra Matchking and JLK VLD bullets but load them to fit in a standard AR magazine.

I don't remember why they fizzled out, pretty sure cost was a big part of it, at the time you could use LRP magazines and load 80 grain SMKs plenty long for most rifles. If you shot a lot, the cost would swing in favor of LRP magazines and conventional lead bullets pretty quickly.

Because the core was compressed powder, ATF didn't care, they were much closer to frangible than armor piercing.

 

[jmorris]

Looking at these photos of the Speer African grand slam bullets.

http://www.armslist.com/posts/36206...rican-grand-slams--458-tungsten-core-500gr-25

Looks like they just have a cylinder of tungsten installed from the bottom, maybe not unlike like installing something into a HP, plastic tipped bullets.

The easiest way, if you already have a hollow base bullet, to make them would be to use tungsten TIG welding electrodes. Talk to an old welder that doesn't ever throw anything away, as even if they are too short to fit in the torch any longer, they would still be long enough to make a core.

Most of mine are the 2% thoriated style that the Danish welding institute wants to phase out because they are radioactive but I have lots of pure tungsten too.

you can get them up to 1/4" diameter. It can be worked easy as long as your using an abrasive method. I sharpen them to a point with a regular sanding belt/disk all the time.

 

[briandg]

The grand slams used to be a little more blunt, with a really flat meplat. Tear a plug through anything.

I can't imagine what would happen if one of those in 378 hit steel. But, the only reason they went out of business is that the A Square solids came out in that bronze monlithic. the Tunsten filler allowed a lot more powder space and velocity, but automatic lathe turned bronze was much cheaper and probably performed as well.

A square's bullets were almost frightening.

 

[Jimro]

Once you get into dangerous game bullets, specifically solids, it's really difficult to justify adding Tungsten for a higher BC since the bullet shapes are not designed for high BC in the first place.

But with modern powders, even the relatively small case volume for bore size 458 Win Mag is perfectly adequate with a solid gilding metal or brass slug. People will always want "more" from their handloads at first, at least until they get to the point where they realize if they really want a 458 Lott, they should just buy a 458 Lott.

Especially since pretty much any "safari" caliber with a brass solid, or thick cup FMJ round nose, is going to provide all the penetration needed to do the job.

Jimro

 

[Jim Watson]

There was once an outfit that made ultra heavy hunting bullets.
They had a tungsten base core for weight and a lead nose core for expansion.
The high density of the tungsten meant you could have a 150 gr 6mm or a 300 gr .30 in 100 and 220 gr jackets so the length was not excessive for the twist.

There was an outfit that made pistol bullets with unsintered tungsten powder cores. The idea being a frangible bullet having the fragments heavy enough to spread out in tissue for a low overpenetration defensive round. Super Glaser.

There are solid copper and bronze target bullets for some of the monster magnum ultra long range rounds. The numerically low form factor boattail spitzer shapes are precisely made on a lathe. I am thinking the difficulty of inserting a tungsten core perfectly centered would outweigh the added sectional density

 

[jmorris]

There are solid copper and bronze target bullets for some of the monster magnum ultra long range rounds. The numerically low form factor boattail spitzer shapes are precisely made on a lathe. I am thinking the difficulty of inserting a tungsten core perfectly centered would outweigh the added sectional density

If your turning every bullet on a lathe (hopefully a CNC one with a bar feeder) it would be pretty easy to machine a pocket for the core concentric with the machined shape.

 

[Jimro]

Runnout on a lathe is generally in the ten thousandths range. With tolerance stacking between the insert and the jacket, it's not going to produce highly balanced bullet across the entire lot of bullets, so you'll get group expansion due to bullet imbalance compared to a monolithic turned bullet or a traditional reverse drawn match bullet.

Don't get me wrong, they wouldn't be any more imbalanced than a Combined Tech bullet with their steel retainer cup, but there are reasons those bullets aren't winning matches (they cost too much compared to more uniform and cheaper match bullets).

Jimro

 

[RC20]

You guys keep missing the point.

If it has Tungsten its cool, and cool is what can sell.

As long as its expensive and exotic people will buy it.

Just look at all those new calibers that do what the existing calibers did just fine.

 

[Jimro]

You guys keep missing the point.

If it has Tungsten its cool, and cool is what can sell.

As long as its expensive and exotic people will buy it.

Just look at all those new calibers that do what the existing calibers did just fine.

You mean like the 307 Winchester, and 308 Marlin? Or the 338 Federal? 6mm Remington? 264 Win Mag? 350 Rem Mag? Maybe the entire Winchester Super Short Magnum line? The RSAUM line?

There are a lot of things that are introduced to a lot of fanfare that just...fade away...

We've already had tungsten core bullets on the market, and they didn't last. Reintroducing that won't change history.

Jimro

 

[jmorris]

Runnout on a lathe is generally in the ten thousandths range.

Not any lathe I use, maybe you meant tenths of a thousandth?

In any case if you are machining something from bar stock runout in the chuck would not matter, unless your stock is the diameter of the finished product. Say you start with 1/2" bar stock even if the Chuck was out of alignment that would be turned off going down to the projectile diameter, same would go for the bored hole down the center.

I do agree with the lack of usefulness of said product though for the work that would go into it (cost).

 

[Jimro]

Yes, one ten thousandths (0.0001") of an inch range, four decimals of precision. That's the difference between someone trained by mathematicians and a machinist. My Dad always defaults to a thousandth and goes from there (tenths for him are 0.0001 and tenths for me are 0.1) and it is easier to put the actual decimal onto a drawing I make so I don't have to translate to machinist speak when I ask him to make me a part

If you are boring the "jacket" and it is that much off, then the insert, even if perfectly cylindrical, will be that much off.

Deflection = 24(pi)(Velocity/twist)(Time of Flight)(Center of Gravity Offset)

Twist, Deflection, and Center of Gravity in inches, velocity in FPS, time of flight in seconds. 24 is the correction factor between twist, velocity, and time of flight to get everything in the correct units at the end.

Notice that bullet mass isn't part of this equation, just center of gravity. But this should explain why multiple part bullets don't fare as well accuracy wise as simpler bullet designs. A bullet like a Partition or A-Frame with distinct front and rear heavy areas is very difficult to get good balance across the entire lot of bullets as dies wear unevenly and things get ever more off center, of course for hunting they'll fly true enough to earn their stellar reputation for terminal ballistics.

Monolithic lathe turned brass bullets have been the "record breaking" bullets for ultra long range, and reverse cup match bullets with lead cores have been the winners for long range (the J4 jacket entry into the market shook up the competitive shooting world quite a bit). Getting the jacket uniform is always the hardest part about making a match bullet, if the "heavy core" is out of true, dispersion happens.

Anyways, this is why the slowest possible twist rate with the most balanced bullets at the highest possible velocity are desirable for best accuracy (the 30 BR crowed is running between a 1:16 and 1:18 twist most often). This maximizes V and minimizes ToF, and minimizes the impact of Twist on bullet imbalance.

Sorry for being longwinded, but that is why complex bullet designs involving inserts aren't generally match winners.

Jimro

 

[RC20]

Good read, happy for long winded. Add paragraphs.

I am just having fun, it of course makes no sense.

Still coming out with non belted magnums, renaming old cartridges back to old terms after try at new and all that.

222 is probably still the overall champ for target and varmint, people still try to top it, human nature, there just has to be a better mouse trap.

Me? I am think of a 7.5 Swiss build just because its doable, lots of good stuff and not too many are doing it.