Projectile Core Density

P

pcammo

New member
A couple interesting comments were made in another post about bullet core material in relation to accuracy and exterior ballistics. Rather than hijack that thread, I will post my question(s) here. Do you think that a bullet with a solid copper core (X-bullets and their progeny) are any less accurate or precise downrange than a typical lead core design? How do you think the light and heavy core bullets of the same mass and general profile compare ballistically? Specifically, retained velocity and wind drift.
Thanks,
John
 
Yes in their original design I believed the x bullets were 'less accurate' than a standard cup and core bullet.
I still believe, although I would be hard pressed to prove it, that the cup and core bullet is the most accurate bullet made. I use and have used Barnes solid copper bullets with great success and at least for big game at under 300 yds are more than accurate enough.
It is the ballistic coificient that determines how well a bullet performs down range and not necessarily the core make up. At extended range are where you will see the benefits of the heavier core bullets...not a fact just an opinion.
 
The X bullets might be less accurate, but it is not because they are solids. That is a bad connection.

There have been several makers of quality solid bullets that were match grade. Lost river was one of them (now TU).

Many think solid bullets are not accurate, but that is because for a given weight range, they need a faster twist cuz they are ~30% longer than a lead core of the same weight.

A 30 cal 180gr Solid brass/bronze VLD needs a 8" or 7" twist - when shot in a 10" barrel, accuracy sucks.


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FCSA uses solid bullets in 50 BMG matches with great accuracy. 4" groups at 1000 yards is good accuracy.

Barnes gives us the G-1 coefficient for the .30 180grain TSX BT of .453
 
I agree, the accuracy may be there for some light core bullets. I am still curious how people model the flight path of said bullets. In several rifles I have noticed a substantial deviation in bullet flight path from G1 for the TSX in particular. I have even derived G5 and G7 coefficients from 200 yd track data. None of the models provide adequate prediction past 500 yards. We are talking about differences of 10+sd.
John
 
I have shot TSX out to 300 yards on paper but they have not shot as good as my lead core bullets. So I never used them on game. I have done some reading on the long range hunting forum about terminal performance on game. I understand that the X bullets require a certain amout of velocity for the pedels to open up and expand. Well shooting distances out to 500-600 yards there will be less velocity on target. I wonder if these bullets would expand well or just act like a FMJ on game.

I would think G-5 would be the appropriate choice, but Sierra's webpage states "Although we expected G 5 to be best for the boat tail bullets, the tests showed that G 1 was better." Copper bullets may fly different than lead.

I will stick with lead personally.
 
Isn't the us army fireing solid rounds out of the .408 CT? and doest that bullet/rifle combination hold the worlds best ultra long range groupe to date? And I also believe they are shooting a solid slug out of the 416 barret as well.
 
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It is sort of funny. I just ran a search of the past 5 years of federal ammunition contracts, proposals, and requisitions and guess what. In the small arms category (.50 cal and under and some shotshell) I find .22LR, .38Spl, 9mm, .45 ACP, .45 Colt, .22CB, .22 Short, .32 Short, .380 ACP, .32 Long, 5.56 (of many flavors), .357 Mag, 6.8 SPC, 12 Ga., 20 Ga., .300 Win. Mag., 7.62 NATO, .30-06 Sprg., .25 ACP, .338 Lapua, .50 BMG, .50 Spot., 10 Ga (blank only), .40 S&W, 7.62x39, 7.62x25, 7.62x54R, 5.45x39, 9x18, .45-70 Government...... plus some others. However, I find no mention of .408 CT, .416 Barret or anything in those bore sizes. I did have to filter out all the baseline crap (less than $1000.00 net transactions). I realize that some discretionary spending does take place that is not recorded.
John
 
Quote:
Isn't the us army fireing solid rounds out of the .408 CT? and doest that bullet/rifle combination hold the worlds best ultra long range groupe to date? And I also believe they are shooting a solid slug out of the 416 barret as well.



The 408 CT holds no records.

That was a lot of sales talk from Chey-Tac made by a guy named Dean Michaelis.

It turned out to be BS. Dean took a 408 down to Quantico to demonstrate it. Well, to start, there were serious pressure signs (~65Kpsia), and at 100 yds, the group was 6", and he couldn't keep the bullets on the target frame at 1,000 yds.

When one of the military guys said something about that, he threatened to take him out behind a building and beat the crap out of him.

That pretty much killed the 408 for the military, and shortly after, Lost River Ballistics went out of business, and Dean Machaelis went off to nursing school.

The 408 CT is now among the many dead cartridges, and owners are having a hard time finding a steady flow of brass. Chey-Tac is in new hands, and is still trying to promote it, but the biggest problem is that no military is going to buy firearms from a small company that controls the supply of brass and bullets. They should have known that from the beginning.

The other problem is that now that Barrett has the "416 Barrett", based on the 50BMG case, no one with half a brain will buy a new 408 because of the brass problems.


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I thought this thread was about core density lead core vs. copper? Lead is denser the periodic table proves that. and the denser a core the better flight profiles, the only thing a solid copper projectile has goung for it is that is will have to be longer to maintain the same wt. Longer = better B.C. at the same velocity
 
Does a longer bullet of equivalent mass really equate to better down range performance? I agree that Ingalls and related models tend to predict this. I am ashamed to admit it, but I had never fired a Barns bullet past 500 yards till now. I am amazed at my inability to predict drop and wind drift with these bullets.
John
 
Quote:
Isn't the us army fireing solid rounds out of the .408 CT? and doest that bullet/rifle combination hold the worlds best ultra long range groupe to date? And I also believe they are shooting a solid slug out of the 416 barret as well.



I don't recall with 100% certainty if the .408CT is a solid projectile or not, but I believe it is, and I know for fact that the .416 Barrett is a solid. And as Catshooter said before me, .408CT at best was a bad joke. It had it's fifteen seconds of fame in the movie "Shooter" and had a hard time believing that a soup can could be hit from any distance, even in the form of a script.

Chupa
 
This is an interesting post. The most shooting I have done using Barnes TSX bullets has been with the 62's in my 223AI.

I've shot them for groups out to 5 and 600 yards, even from 2-400yards they do not shoot as well as the more traditional 75Amax. They (Barnes') still shoot MOA or a little better.

I chalked it up to load work up with that bullet. Due to the cost I didn't do a very extensive load work up and MOA at 200 yards was my goal for that bullet. I don't plan on shooting deer at stupid ranges with the 223 so I wasn't too concerned.

I do know I'm seeing a higher BC than what Barnes is giving on thier website. What I mean is that after I got my real world drop data I had to up the BC in the software to make it match up to what they acutally shot. That was using the correct altitude, weather, inputs and chrono speeds for that day. /ubbthreads/images/graemlins/confused1.gif
 
That is pretty much what I am seeing as well. At about 500 yards or less, the drop is less than predicted. At beyond 500 yards (at least with these 180gr. TSX starting at 2900fps) they drop much more than predicted. At all distances they are more affected by wind that traditional lead core SBT. From an empirical "hand waving" approach this makes sense. But it does not fit the Ingalls model.
John
 
Quote:
The X bullets might be less accurate, but it is not because they are solids. That is a bad connection.

A 30 cal 180gr Solid brass/bronze VLD needs a 8" or 7" twist - when shot in a 10" barrel, accuracy sucks.


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You only need 1 in 11 to stabilize a cored bullet! 190 grn's! By the way VLD!!! http://www.bergerbullets.com/
 
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