Discussion in 'Firearms & Ammunition' started by Alchemist, Apr 21, 2017.
Yes that’s why we don’t want brown bear hunters to use Partition.
I’ll definitely not use them again. I’m sure they are fine on thin skinned game at proper velocities but I’ve been very happy with the A Frames that I have been using. These two were recovered from a zebra and a blue wildebeest both shot at around 150 yards from my 8mm magnum.
Never seen a Partition expand like this. I've seen cup and core bullets do this. Is this the lower part of the bullet where the partition is located or the front core ?
I’m not sure if it was the front or rear core. The jacket had separated. The pictured jacket and core piece pictured were recovered just under the skin. No bone was hit. This was my first time hunting with partitions, so I have no previous experience to compare, but to say I was disappointed would be an understatement.
I would be as well. Was this a reload or an off the shelf box ? The chunk of lead is substantial but I can't tell if it's a front core, I'd be curious to know the weight of the jacket, it will tell whether it holds the partition and the rest of the lead. If and when you get a chance. Do you still have the box if it is off the shelf ?
The only thing that would make a bullet behave like this is a slow barrel twist resulting in poor stabilization. Were the entry holes round ? Mind you, there are also times where entry holes are round but a bullet tumbles after penetrating medium by a couple of inches. A zebra is very dense.
It is not very likely that this a poorly stabilized bullet. Partitions aren't excessively long and usually stabilize quite well. 200 grains isn't long for caliber in 8mm. It has the form factor of a 180 grains in .30 cal which is very middle of the road.
The make of your rifle can give an idea of the barrel twist. If, big IF...it is excessively slow, there lies the problem. Otherwise it is bullet failure.
3000 fps is pretty fast for a partition, in my experience the NP work very well at a muzzle velocity of 2500-2800 fps.
There have been many comments on other threads about the Partition not being the best choice for DG. The front grenades and the back end drives forward without much expansion. Works fine on smaller big game species but probably not the best choice for larger game or DG. I much prefer the Swift A-Frame or even the Accubond.
Nice write-ups! I too used a 300 WM. Only I used Federal factory loaded 180grn Trophy Bonded Tipped ammo. Didn't have enough time to work up a handload. The factory loads were just over 2900 fps which is perfectly acceptable in my book. (Though we will be working up a handload.). I found the bullets and bought 100. They weren't easy to find and after corresponding with a Federal tech guy I found out they only do limited batches of the loose bullets. Gotta get em when they appear or back order.
I am a huge fan of NPs but not for African game. The TBBCs and TBTs are similar to the NPs only much tougher.
You can review my post on the TBTs a couple pages back if you like. And yes, Waterbuck are tough!
Kudos on your hunt.
The rifle is a Remington 700. Twist is 1:10. I'm confident that stabilization wasn't the issue. It stabilizes Swift 220s just fine. I'm pretty sure I was just driving them too fast for the design of the bullet. These were hand loads. Average velocity was right around 2990 fps on the chrony. I still have the jacket and can weigh it, but you can look at the picture and see that there is no lead present.
The NP's were designed quite a few years back and the partition would be on the thin side as they would not have been meant to be driven at current magnum velocities I would think. I 180grain NP in my 300 SAUM on pigs no problems. Would I drive them out of a 300RUM, no way.
When using large case magnums I believe (just my belief) you need to use mono-metal or modern bonded lead core bullets like the A Frame and similar. Especially for heavy built game.
That's the information I wanted. You're correct about the twist. Even 1/12 up to 1/13 for that particular bullet is enough to stabilize properly. I worked it out with the Greenhill method. The rifle's barrel twist was made specifically for that cartridge by Remington and thank you for showing a larger image of the cup. It unfortunately seems to all point out to bullet failure.
I use 160 gn nosler partitions in my 7mmstw at 3,200 fps.
they are the load for game from fallow deer and under, and do this job well.
barnes for bigger game.
Left, 100 grain TTSX, .257 weatherby MV 3575, mule deer, 150 yards, straight on frontal hit, bullet stopped in the backstrap past the left shoulder.
Middle, 185 grain TTSX .338 win mag, MV 2950, Pronghorn, 400 yards, Quartering away, hit the last rib
in the ribcage and stopped in off shoulder.
Right, 225 grain TTSX .338 win mag, MV 2700, Bull elk, 381 yards, quartering forward, hit left shoulder and stopped under skin off side by the last rib
Elk in my Avatar was taken with the 225 TTSX, .340 weatherby, MV 2975, 125 yards, quartering forward, hit the front of the shoulder and exited in the middle of the ribcage off side
All animals were down with in 14 yards of being hit
We used Partitions our first trip to Namibia and did not loose anything but only found pieces of bullets..Last time we shot Scirrocos and every recovered bullet had a perfect mushroom(like the pics show)..They penetrate like a bat outta hell so don't want to lung shoot 'em...Both were 30/06 factory loads...Next time we're going with Swifrt loaded A-Frames in an 06 and a 300Win mag....Tried TB Tips on deer this year and they make a good mushroom but open too quick so pentration was shallow.
These all look good. What is surprising is how with moderate speed the 185 grains opened up even at 400 yards. It's good to know.
I used that 160 grn. Partition in a 7 mm magnum for many years, at 3000 fps. It served me very well. I made shots at extended range. It didn't lack in penetration and was extremely accurate. I think on very dense plains game like zebra and sable Partitions may at times behave differently although I shot some stouter game with Partitions in 30, 338 and 375 caliber with no problem and to me, very good results. I realize there's plenty of choice on the market which is normal, it is an older design. I still use them as well as Barnes and a few others.
The 185 load was at 2000fps at 400. And the 225 was around 1950. Barnes lists 2000 for reliable expansion. The way this bullets look l don't think l would go much below that. The 225 was almost no weight loose
I wonder if the Nosler Partition 8MM bullet, in 200 grain was possibly designed specifically for the 8x57 Mauser cartridge.
In other words, designed for reliable expansion when impact velocities stay between about 1800 fps to 2300 fps ?
Grumpy old man rant over,
That makes sense. At muzzle velocities of 2400 to 2450 fps, it would need to expand at less than magnum initial velocities.
The problem with attempting to design a bullet that will always perform as desired is that there are too many variables to make it a realistic quest. Some of the variables are: at what velocity will the bullet strike the animal; What is the elasticness/resistance of the animals skin; what is the durability of the animals bones that will be contacted; what is the toughness of the muscles that will absorb the bullet; and others such as how mush dried mud will the bullet contact before it gets to the animal. So what we end up with is a bullet that will most of the time perform as desired if we match the bullet to the desired performance criteria. Several years ago I researched the performance of several 30 caliber bullets. They were fired into water filled gallon plastic jugs at two velocities, 2700 and 3100 fps. the medium was not intended to mimic a game animal but it did have two valuable characteristics: It provided the same resistance for each bullet and it did provide a valid comparison of one bullet compared to another. Additionally, the increase in velocity showed the effects of a 400 fps increase. There have been many bullets in that testing that are no longer available and many that are now available that weren't in production at the time. I've considered repeating the project with presently available bullets and also testing larger bore bullets- the 375 and 458 come to mind. If so, I'm going to need a truckload of plastic jugs as it will take a bunch of them to stop those 300 and 500 grain bullets.
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