Deep Curl vs Partition


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Kachok
April 8, 2013, 07:50 AM
Looking at a few reports from hunters it seems to me that the new Deep Curl has very similar weight retention properties as the legendary Nosler Partition, around 80-90% at close ranged standard rifle speeds and around 65-75% on close ranged shots with magnum rifles. Mind you this is a very small sampling since people don't normally recover either one of those bullets given the very deep penetration. Since Noslers have shot up in price recently, and the Deep Curl has performed so remarkably well for me at the range I was thinking of giving them a try in the woods. I know weight retention is only part of the equation, but do you guys think a value bullet could hang with a legend? If not why?
While weight retention is almost identical one visibly different with the Deep Curl is it's tendency to turn (mostly) inside out at very high impact speeds, but it still retains it's weight despite it's extensive deformation. Partitions make a more uniform mushroom at a wide range of impact speeds, though push them fast enough and they can shed their front core, but they still perform great even in that rare worse case scenario.

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Mobuck
April 8, 2013, 09:08 AM
In my opinion, the two bullets differ considerably in design and performance.

The Partition will expand even at long range/low impact velocity but will "blow off" the front core in a high velocity impact. This is not a bad thing since the rear core will continue to penetrate with excellent results. I consider Partitions an "any game" bullet having killed animals from coyote to big bull elk with Partitions in .257,.284, and .308 diameters.

The Deep Curl is designed to expand with a larger frontal profile and therefore is likely to penetrate less. How it performs at a high impact velocity, I don't know. I would call them a medium game bullet.

Patocazador
April 8, 2013, 02:21 PM
I have only shot partitions at game animals for the last 35 years. They are good insurance.
I once shot a deer that had a few grape vines a foot in front of the deer between us. The entrance hole was 4" in diameter. I couldn't imagine what had happened. I figured I got a dud bullet or loaded a varmint bullet by mistake. Then I saw a clipped grape vine that the bullet hit first and expanded. The back half pushed that expanded bullet right through the 100 lb. doe.

35 Whelen
April 8, 2013, 04:19 PM
For deer and hogs, I see no need in either. I've used Partitions on deer in the past in a 257 AI and a 280 Rem. and they seemed like a waste of money because the deer were no more dead than those shot with run-of-the-mill cup and core bullets from Remington, Sierra, and Hornady. I remember making an angling shot once on a doe with a 6.5x55 and a 120 gr. Sierra. It did exactly what it was supposed to do and travelled from behind the last rib up through the left lung. A couple of years ago my wife killed a pretty good size boar with a 6mm Remington and a homely 100 gr. Hornady pre-Interlock bullet.

But on the other hand, lots of R&D folks at the bullet companies need people to buy these "new and improved" bullets!

35W

DM~
April 8, 2013, 04:42 PM
In my opinion, the two bullets differ considerably in design and performance.

The Partition will expand even at long range/low impact velocity but will "blow off" the front core in a high velocity impact. This is not a bad thing since the rear core will continue to penetrate with excellent results. I consider Partitions an "any game" bullet having killed animals from coyote to big bull elk with Partitions in .257,.284, and .308 diameters.

The Deep Curl is designed to expand with a larger frontal profile and therefore is likely to penetrate less. How it performs at a high impact velocity, I don't know. I would call them a medium game bullet.

I'm with you 100% on the NP's!

I've had them work on everything from coyotes to brown bears, and that's why i use them so much! I can work up a load for the biggest big game i'll shoot with that rifle, and then use the SAME rifle/load on everything i hunt, big and small, knowing it will work just fine.

I don't care if NP's do cost a little more, it's not like i shoot 50 or 100 big game animals a year with them, so the cost it's all that much!

DM

Kachok
April 8, 2013, 04:52 PM
I don't think anyone in their right mind would argue the terminal performance of a Noser Partition, they are simply beyond reproach in my mind, one of my favorite bullets without question. Only thing I hate about Partitions is they shot up in price around $12-$14 a box around here in the past six months. I like to shoot alot to keep my skills sharp and $40 for a box of 50 is quite painful if you practice with your hunting load (as I do) When the panic dies down I might be able to get some of those overrun specials that Nosler has from time to time, but for now they have nothing. Heck I cannot even find NPs for most of my rifles even if I could justify the extra $$$ at leased I still have some 125gr 6.5mm and 140gr .270 left, but nothing for any of the 30 cals or 7mm. I found DCs on sale for $26 a box and bought a ton of them for every caliber I load. If they perform half as well on game as they do at the range I will be one happy hunter.
35W while I agree that deer are unlikely to ever notice the difference seeing as the real advantage the Partition and other premium bullets have is deep penetration which for any caliber north of .243 is probably excessive on average sized whitetail. Partitions really come into their own when you might run across something much thicker bodied, like a 780lbs feral hog for example :) The other application for such tough premium bullets is that they hold up to high speed impacts very well so those of us who feel the need to shoot deer at 50 yards with their 7mm Rem mag don't have to worry about a blow up, I don't use my 270 WSM in the woods seeing as that is WAY too much gun up close, but if I did my 140gr NP would be an easy choice.

tahunua001
April 9, 2013, 01:30 AM
ok I don't know much about ballistics so this could be completely wrong but doesn't the deep curl use bonded jackets(like interlocks and accubonds) to help weight retention while partitions are just that, partitioned lead slugs held together with a copper jacket?

just a newb notion but one would think the partition would fragment and leave multiple wound tracts while the deep curl would just mash and mangle without losing much weight.

I have no personal experience with the partitions though i just got an old box of them for use in a 6.5 jap rifle that I plan on experimenting with however I do use deep curls in my 300 weatherby for elk. a 180 GR deep curl at about 100 yards goes into an elk neck and takes a couple vertebrae with it out the other side with no fragments to be found... never did recover the bullet but I would have loved to see what it looked like

Kachok
April 9, 2013, 02:40 AM
They both retain about the same amount of weight for different reasons, the Deep Curl retains alot of weight because the lead is chemically bonded to the jacket, some of the lead that is not in direct contact with the jacket will flake off at high speed creating small separate wound tracts, BTW I use the term jacket very loosely because the Deep Curl is not a jacketed bullet it is something else, the copper surounding the lead is plated on, a process that is different then any other bonded bullet and the reason they are 1/2-1/3 the price.
Partitions on the other hand have no bonding of any sort, making them the only real premium bullet on the market that is not bonded or mono metal. It retains weight because it will expand to the partition and then it has to stop, this also allows Nosler to make the front jacket taper very thin giving the Partition some very quick expansion for a deep penetration bullet, hence the reason they are so popular with people who hunt a wide variety of game, the same Partition that will go through a moose on a broadside shot will still expand reliably on a small yote.
Other bullets are more specialized like the Sierra Game King, devastating bullet on deer, but people who have used them on larger game say they have frequent issues with core jacket separation. Never had that happen myself, or if it ever did both core and jacket left out the huge exit wounds that bullet tends to produce.
BTW Interlocks are not bonded, you are thinking of the interbond, interlocks are alot like the ol Remington core-lokt, that design works well, it does not retain weight like a bonded bullet especially on a heavy bone strike but plenty adequate for deer, if they do come apart they usually get to the vitals before coming unglued which can make for some impressive quick kills.

Andrew Leigh
April 10, 2013, 12:33 AM
Was browsing a ballistics site recently which had some wet pack tests on bullets I was interested in. I am an Accubond user who considered Partitions, but on the range the Accubonds grouped better so I stayed with them. I was wanting to move to the Partitions which I understood was a better bullet and in reality for hunting purposes the the accuracy difference was not material. Anyways you may find the results interesting, I shoot 180's hence the table;

Bullet mass and Type / Speed / Expanded dia. / Penetration / Retained mass.

180 gr Federal Fusion 2745 fps 0.693" 12.6" 134gr / 74%
180 gr Hornady Interlock 2750 fps 0.550" 15.7" 103gr / 57%
180 gr Nosler Accubond 2765 fps 0.582" 13.0" 127gr / 71%
180 gr Nosler Partition 2680 fps 0.480" 16.0" 122gr / 68%
180 gr Remington Core-Lokt 2640 fps 0.690" 12.5" 129gr / 72%
180 gr Swift A-Frame 2750 fps 0.590" 21.7" 177gr / 98%
180 gr Winchester Silvertip 2766 fps 0.665" 10.9" 135gr / 75%
180 gr Woodleigh Weld-Core 2750 fps 0.870" 15.7" 165gr / 92%

That A Frame is rather impressive!

Can't seem to get the table neat, apologies.

Walkalong
April 10, 2013, 10:34 AM
I recently did some informal testing of some bullets in .300 BLK. Water jugs, phone books and clay bank.

125 Gr TNT (2050ish FPS)
110 Gr V Max (2150ish FPS)
125 Gr SST (2050ish FPS)
130 Gr Hot Core (Similar to the Deep Curl) (2050ish FPS)

Jugs:

The SST blew the back out of the jugs impressively.

The TNT and V Max tended to blow them apart, but front to back like an explosion inside going all directions.

The HC blew out the back, but less impressively.

Phone books:

The TNT and V Max did OK on the three wet phone books, but died in the dirt backstop within four inches.

The SST blew out more of the paper, and then came apart in the bank, but went more like six inches in.

The HC blew through the phone books and 10 plus inches in the bank.

Clay bank:

The TNT and V Max blew apart with little penetration, blowing dirt back out.

The SST blew some dirt back out as well, separated from the jacket, and the lead core penetrated a few more inches.

The HC did not blow much dirt back out, but burrowed deep into the bank, never to be recovered. No sign of the jacket left behind. The hole was about 3 inches where it hit and narrowed to an inch and a half as far in as I could see. It was about 15 inches in.

I had one 155 Gr A Max and it fared about like the SST, leaving the expanded jacket at around four inches into the bank.

Very informal, but the HC held together much better than the cup and core bullets.

I would assume similar performance by the Deep Curl.

I need to find somewhere to test the 130 Gr HC and the 125 Gr SST on hogs.

Kachok
April 13, 2013, 12:43 AM
Was browsing a ballistics site recently which had some wet pack tests on bullets I was interested in. I am an Accubond user who considered Partitions, but on the range the Accubonds grouped better so I stayed with them. I was wanting to move to the Partitions which I understood was a better bullet and in reality for hunting purposes the the accuracy difference was not material. Anyways you may find the results interesting, I shoot 180's hence the table;

Bullet mass and Type / Speed / Expanded dia. / Penetration / Retained mass.

180 gr Federal Fusion 2745 fps 0.693" 12.6" 134gr / 74%
180 gr Hornady Interlock 2750 fps 0.550" 15.7" 103gr / 57%
180 gr Nosler Accubond 2765 fps 0.582" 13.0" 127gr / 71%
180 gr Nosler Partition 2680 fps 0.480" 16.0" 122gr / 68%
180 gr Remington Core-Lokt 2640 fps 0.690" 12.5" 129gr / 72%
180 gr Swift A-Frame 2750 fps 0.590" 21.7" 177gr / 98%
180 gr Winchester Silvertip 2766 fps 0.665" 10.9" 135gr / 75%
180 gr Woodleigh Weld-Core 2750 fps 0.870" 15.7" 165gr / 92%

That A Frame is rather impressive!

Can't seem to get the table neat, apologies.
That is a very interesting result, the Fusion, A-Frame and Weld-Core all seemed to give impressive results in their class.
Few things that surprised me though.
1. I would have thought the Partition would have expanded a bit wider then that, they are not known for being light in the expansion department.
2. The Silvertip retained alot more weight then I would have expected (they are known for being a bit frangible) but it's penetration was still on the light side right about where I figured.......weird.
3. The Core-Lokt looks tough, until you look at the speed, it was tested 100fps slower then alot of the others, would have liked to have seen it at 2700+fps like the Interlock and Fusion. 100fps difference is major when you are comparing terminal performance, especially weight retention which always degrades at higher speeds.
The Fusion expanded nice and wide as predicted, but contrary to popular belief the Deep Curl is NOT the same bullet as the Fusion, the DC is a flat based more heavily tapered bullet (for even wider expansion) while the Fusion is a boat tail design for improved external ballistics. Only thing they have in common is their unusual construction method, plating copper onto a lead core.

Andrew Leigh
April 13, 2013, 12:58 AM
The source information is to be found here if you want to have a closer look. Read the entire site, I find it real informative.

http://www.rathcoombe.net/sci-tech/ballistics/wounding.html

Cheers

Geno
April 13, 2013, 05:03 PM
Thanks for the link, Andrew. Very interesting reading.

Geno

T.R.
April 14, 2013, 02:28 PM
My wife has taken many big game animals with her 6.5mm Swede and Nosler Partition bullets. In contrast, I load the Speer 270 grain Deep Curl for my 44MAG carbine and 50 cal muzzle-loader w/sabots.

Both bullets share this performance: bullets that penetrate right through the animal. Result is a dead animal with large exit hole.

TR

Kachok
April 14, 2013, 06:32 PM
You load her the 125gr or 140gr Partition? That is one awesome bullet in the Swede. I personally think premium bullets are better suited to smaller calibers. A 30 caliber clearly needs no fancy bonding to get more then adequate penetration on a deer, but a .243 or quarter bore might be prone to a little under penetration with run of the mill cup and core especially in lighter weights. The .264s are the smallest caliber I am confident in using plain jacketed soft points or unbonded poly tips, but I stick to the heavier weights unless it has an exceptional reputation as a tough bullet (aka Hot-Core core-lokt...etc)

witchhunter
April 15, 2013, 09:28 PM
No argument from me on the Nosler Partition. For over 35 years I have not shot anything else since the first one. Initial shock and excellent penetration. I am afraid of the solid copper Barnes types, they look like they would work, but I have seen the Partitions hit, expand, and penetrate. Best of all worlds. If anyone from Nosler is reading this I could always use some 115 gr .257's......

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