Why not Tungsten match rounds for 70% greater ballistic coefficient? - Page 2

briandg · June 27, 2016, 11:14 AM

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 · June 27, 2016, 05:32 PM

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 · June 27, 2016, 06:10 PM

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 · June 28, 2016, 08:25 AM

Quote:

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 · June 28, 2016, 08:47 AM

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 · June 28, 2016, 01:36 PM

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 · June 28, 2016, 02:23 PM

Quote:

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 · June 28, 2016, 05:43 PM

Quote:

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 · June 30, 2016, 02:25 PM

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 :P

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 · June 30, 2016, 06:49 PM

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.

June 27, 2016, 11:14 AM	#26
briandg Senior Member Join Date: May 4, 2010 Posts: 5,468	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. __________________ None.

June 27, 2016, 05:32 PM	#27
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	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 __________________ Machine guns are awesome until you have to carry one.

June 28, 2016, 08:47 AM	#30
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	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 __________________ Machine guns are awesome until you have to carry one.

June 30, 2016, 02:25 PM	#34
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	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 :P 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 __________________ Machine guns are awesome until you have to carry one.

June 27, 2016, 06:10 PM	#28
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,542	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

June 28, 2016, 01:36 PM	#31
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	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.

June 30, 2016, 06:49 PM	#35
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	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.