Home Forums Hunting & Shooting Hunting Rifles Greatest Cup and Core?

Whttail,

No, Speer's Hot-Cor process does NOT bond the core to the jacket. A lot of people believe differently, but it's easily disproved by sectioning one: The core doesn't stick to the jacket, anywhere. The latest version of the Speer Grand Slam is made the same way; essentially it's a Hot-Cor with a heavier jacket.

Actually the earlier Grand Slams were probably made the same way, but featured a two-part core, with the core in the rear of the bullet made from a harder lead alloy, plus a ridge around the inside of the jacket (much like the Interlock ring) to help keep the rear core in place.

Then there's the Speer Mag-Tip, with a jacket somewhere between the thickness of the standard Hot-Cors and the Grand Slam. But I don't think it has an inner core-locking ring.

In both the Mag-Tip and the Grand Slam, only the rear section of the jacket is heavier. The front is thinner to promote expansion. This is how the original Remington Core-Lokts were made as well, but only the round-nose versions have the thicker rear jacket anymore. The pointed Core-Lokt jackets were thinned around 20 years ago to make manufacturing simpler.

Contrary to another popular belief, the jackets of Core-Lokts never did have an "hour-glass" contour to keep the rear core inside. The only bullet I'm aware of that did was the Federal Deep-Shok. It was designed as a cup-and-core that would act like a premium bullet. It worked exactly as designed, but proved just as expensive to manufacture as a premium bullet, so was dropped within a couple of years.

Thanks MD. Given the large disparity in melting points between lead and gilding metal there's obviously other means of proprietary black magic (fluxing agent as mathman called it) involved in bonding the two metals. I used the 165 .308" Deep-Shoks some and did section one to see the hour-glass shape referred to. I picked up 1k of the .243" 90s when they surfaced not too long ago but haven't taken the time to do much with them yet. From what I've seen of the Deep-Shoks, Speer should have kept them as their premium bullet, rather than converting the Grand Slam into a Mag-Tip.

Yeah, that was my take on the Deep-Shok as well! Have tested both the latest version of the 200-grain .30 GS and the 180 DS in dry newspaper, and the DS out-performed the GS in every way. As I recall, 2 of the 5 Grand Slams separated; none of the DS's did.

Also had good luck with DS bullets on the few game animals I used them on; only recovered one bullet, a 180 .30 from a .30-06 that killed a caribou at around 450 yards. The bull was quartering toward me, and the bullet hit the shoulder bone and went on through the chest, ending up under the hide at the rear of the ribs on the far side, in a perfect mushroom. Can't remember exactly what it weighed, but it retained around 70-75% of its weight.

I suspect that if the jackets of Hot-Cors were heated there might be some bonding when the molten lead's poured in, but believe the jackets are room-temp.

Aside from the Fusion and DeepCurl bullets, all the bonded bullets I know of are fused by heating the swaged-together jacket and core. This includes the Hornady Interbond, Northfork, Nosler AccuBond, Remington Core-Lokt Ultra Bonded, Swift A-Frame and Scirocco, Trophy Bonded and some others I've forgotten. Oh, and the original bonded bullet, the Bitterroot. This is how Nosler is able to bond only the rear 2/3 of the AccuBonds, so they'll act like Partition: They only heat the rear.

Heating a bullet to bond it anneals the jacket somewhat. This isn't bad, since a softer jacket is less brittle, so tends to bend with the core, instead of breaking up. But if the jacket doesn't have some other feature to stop expansion, like a partition or heavy base, then both the lead and jacket can come apart if they hit something hard. The bullet comes apart with lead sticking to the fragments!

I can't believe you forgot the Oryx...

Everyone expects perfection. :

I have had great success and stellar performance with the 130g Interlock SP in the 270 Win. On many hundreds of pigs that bullet has held together very well even with MV of 3100+fps.

On pigs and other game, and testing in wet newspaper, it holds together and penetrates as well or better than the 130 NBT.

Going up to the 150 grainers in the 270 Win, and the roles are reversed a bit. The NBT seems tougher than the 150 grain version of the Interlock.


I have also had great success with the 180g Interlock BTSP at MV around 2775fps from the 30-06. The flat base version of that bullet seems just as consistent but the BTSP version seems a little more accurate. Probably because I find it easier to seat straight in the case with my sloppy handloading technique.


I have found the HotCor and Pro Hunters ( and SGK s ) generally to be not quite as tough as the Interlock or the BT. The Sierra seems to be the easiest to get to shoot really small groups.


For me, weighing up accuracy, performance and price (yes I do believe in price as a factor) the Interlock is No.1 for me.

yep need a fluxing agent to get the bond..Back when I made my own 30 cal bullets (corbin setup) they had a bonding/fluxing agent where you melted the lead in the jacket after putting the flux in around the core..

worked great... made a ton of thick copper jacketed bonded core 150 and 168 gr bullets before I sold the setup.

fun extention of the hobby but not cheap...........

learned a lot about bullet construction through the process.

Jorge, the Nosler 180gr BT is a very tough bullet. Even at 300 Ultra Mag speeds. I have used it a fair bit on game up to elk out of my Ultra and it's worked great. Even when encountering bone at close range.

We ain't talking about vacuum cleaners.

Scott,

That's what happens when you get to be "a certain age"....

Silly Poobah, cups are for chicks.

Dan


PS: If I live another 50 years I will not run out of premium bullets. Or cup and core. I can afford to be flippant.

It happened by virtue of the strangest convergence of events ever witnessed in the cosmos. I still can't explain it, but my 7x57 simply loves me. So does my other Rigby.

The Lapua Mega looks like an hour glass to me. That's the only one I can think of with a similar shape but not the best BC for long range. I would trust it holding together on just about anything.

Yes the Lapua Mega is an "hour-glas"bullet.

Speer Hot-Cor is not bonded that's right,but it's important to mention why Vernon Speer choose his way to make a bullet instead if the traditional way with a cold lead core. Speer choose to pour molten core into a jacket.Because the core wasn't formed in a separate operation , no lubricant was needed. By pouring the core no air was trapped between the core and the jacket that could cause oxidation.By eliminating the lubricants and and oxides, a more secure core-jacket grip was possible. He meant a core slipping out if the jacket often was reason to core-jacket separations in traditional cup and core bullets.

Lapua Mega is also limited to .264, .308 & .366 bullets. I think my primary choices for a larger spectrum of calibers would be Nosler BT & Speer Hot-cor (including Mag-tips). Those two bullet lines probably make up 70% of my current bullet stock.

hornady soft point boat tail.

There have probably been more animals killed with the lowly Rem. CorLok than any other C&C bullet. Probably more than what have been killed with premiums.

Millions of hunters go down to Walmart or?, buy the cheapest green and yellow box of ammo that will fit in their rifle and go out and kill hundreds of thousands of deer every year and probably quite few elk.

What do you conclude as a result of that observation?

Multiple Choice:

a) The Core-Lokt bullets are the greatest C&C
b) Core-Lokt bullets are lower than pond scum
c) Travis would use them if he could find them
d) Most hunters are grotesquely ill informed

A lot of light beer gets sold and consumed too. Does that make it good?

The animal that bites more people in the US is the cocker spaniel
the reason isn't that they are more violent or prone to bites the reason use simple.
Most people bit are groomers and spaniel breeds require grooming a lot.
But...
Given that core locks performed in Gary schucttie's test better than any other bullet, even the premiums.
By better I mean held together at a higher speed and expanded at lower, retained weight and depth of penetrating.
Hornady RN was second.

Let's keep this rollin', some of it cracks me up. A lot.

45 million views, whaddya say?