Home Forums Hunting & Shooting Ask The Gunwriters Empty .30cal Nosler Partition

The more analogous scenario would be a passenger in the back of a pickup truck that struck a large tree. Could the passenger bounce off the back of the pickup's cab? Motion of passenger at impact would be forward, but with sufficient resistance (force applied in stopping the truck) the body in the back could in essence bounce and reverse course.

Like I indicated in my original post, I would be surprised if even a large bone would provide enough resistance to a 30 cal Partition for an unrestrained rear core to reverse direction considering the impact velocity it had, but I'm not going to say it's impossible.

I wouldn't be surprised if someone at Nosler knows the answer to our physics problem. If they didn't, they could test the scenario today if they wanted to by simply not crimping the rear core of a Partition and firing it into test media. If 3 bullets prepared the same way yielded the same result, we'd have an answer.

From what I've seen if anything happens to rear cores in violent impacts it's not a bounce back. Rather the rear core is pressing forward so hard that the jacket bulges radially just behind the partition and the rear core material becomes a mushroom shaped plug stuck in there.

Mathman,
I have seen that bulge in Swift a-Frames, but I have necer seen it in Partitions.
Do you have any pictures you could please post?
Thank you.
Alvaro

I have noticed that some bullets bought as separate components do not have a cannelure, while the same bullets loaded in factory ammunition come with it. I have seen in in Nosler Partitions and Nosler E-Tips as well.

In this case it was a Federal loading. Caliber was 300 WSM and ammo was not old.

I have seen quite a few bullets tumble after they hit a big game animal, or in test media. Have recovered them with the mushroom facing "backwards" when the bullet was caught by the hide on the far side. On one of the weirdest occasions, a well-known "premium" .375 bullet apparently tumbled so violently after hitting a broadside Cape buffalo's shoulder bones that it spun through the lung BEHIND the shoulder, and was recovered from the ribcage on the same side of the bull it entered.

No personal pictures. It's just what I've found investigating and it probably was an A-Frame I'm remembering.

Wondering if it did NOT have the rear core when loaded....would the bullet have hit to point of aim? I would think it would have flown off course.

The lead rear core isn’t going to “bounce back” out of the rear of the jacket. It may get ripped from the rear of the jacket from deformation but lead doesn’t bounce too well. The inertia of the rear core will cause it to try to continue in its direction of travel on impact, sometimes bulging the jacket just behind the partition. You can see slight bulging just behind the partition in pabucktail’s photos.

I’ve never recovered a partition from a game animal but have found many of them after they hit a dirt backstop and the inertia of the core will have bulged the jacket behind the jacket.

My thoughts are that the rear core was never there and the front core was shed as Partition’s sometimes do.

The rear core may deform the jacket radially IF the rear core is crimped into place such that the amount of force required to overcome the crimp exceeds the amount of force required to deform the rear core/rear jacket. If the rear core is not crimped, the rear core could respond differently than it normally would because even a thin tube has considerable radial strength.

My guess is, it didn’t have the rear core to begin with. Give the number of bullets produced, absent 100% inspection, a mistake will occasionally make it through. Years ago, I found a Norma .44 Magnum factory load with the bullet seated backwards. Also consider that a bullet is a relatively small, marginally stabile object traveling through an uncontrolled environment, with infinite possible occurrences at an incredible speed...enough speed to provide adequate energy for all sorts of things to happen. Weird schit will happen.

Alvaro,

Did your friend notice any difference in recoil between the first and second shots?

I did some quick, rough estimates, and if the bullet was missing its rear core, the recoil probably would have been about 75% of what a normal round would have. I know I don't notice recoil as much when I'm shooting a deer as when I shoot paper, but 25% less recoil could be noticeable.

Assumptions/estimates:
165 grain Partition with rear core weighing 55 grains (33% of total bullet weight)
H414 66.9 grain powder load launching 165 grain bullet at 3100 ft/sec and 110 grain bullet at 3330 ft/sec (Hornady 7th Edition)

If you look at the OP’s original pics you can see that the base crimp is still there and hasn’t been compromised. In addition there is no swelling of the jacket right behind the partition. Again, leads me to think the rear core was never present.

The Nosler partitions that I’ve recovered from dirt backstops usually show some expansion of the jacket just behind the rear jacket/core as the rear core slams into the partition which, in turn, swells the jacket right behind the partition.

L

I asked him that very same question and he told me he was very excited and concentrated on the stag and he did not notice any difference in recoil, nor noise nor anything. Ufortunately he did not keep the spent case, as it might has provided us with some information like some soothing in the neck-shoulder area, or a protuding and rounded primer ... I am thinking in signs of very low pressure due to reduced bullet weight




I don't think that the base crimp is there... On the other hand I have recovered a few Partitions from game, not too many because it is a bullet I don't shoot much, but a few, and none of them exhibit that bulging right behind the partition, so common in Swift A-Frames.

navlav8r,

This is one of the 150gr 7mm Partitions I recovered in one single cull hunt in Namibia from Oryx, Blue Wildebeest and Red Hartebeest. None stayed inside of anySpringboks or Warthogs I also killed.

The base crimp is quite obvious, as much as I can't see it in the empty Partion pictures.

The bulge that you mention, and that I have never seen in any Partition that I have recovered from game, is not there either. I do not mean it cannot happen, I only say I have never witnessed it in the 15 or 20 Partitions I have recovered from game.

Nice looking Partition you have there.

I don't think that the base crimp is there... On the other hand I have recovered a few Partitions from game, not too many because it is a bullet I don't shoot much, but a few, and none of them exhibit that bulging right behind the partition, so common in Swift A-Frames.
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The experiences you both mention point to the same thing - considerable force is required to bulge (radially expand) the rear core of a Partition. A dirt backstop exerts enough force (resistance) to quickly stop a bullet traveling over 2000 (perhaps close to 3000) feet per second. That violent deceleration exerts considerable force (F=ma) when compared to the forces the bullet is designed to overcome in an animal. The bones of most animals commonly hunted aren't going to provide even close to that level of resistance (force), as evidenced by the effectiveness of Partitions in penetrating almost any type of bone to get to the vitals and often exit the animal completely.

Navlav8r - Additionally, your experiences point to the typical Partition rear core crimp being VERY effective in retaining the rear core because that little crimp has to withstand enough force to translate force from along the axis of the bullet into the radial stresses that exceed the deformation point of the rear part of the jacket, which is a tube.

You probably are very familiar with this from your professional background, but I'm sure for others who are curious videos are readily available showing how much pressure two liter soda bottles can hold before bursting. There's a very good reason why pressure vessels (e.g., household propane tanks) are typically designed as cylinders with half spheres at either end - the ability of even a thin shelled cylinder or sphere to resist radial stresses without deformation.

Reminds me of the videos I saw in our driving class when I worked in Dubai...

Gotta love the not-yet-ignited powder kernals leaving an imprint on the exposed rear lead core. All my recovered partitions exhibit this.

Alvaro,

I have only rarely seen any bulge in the rear of the Partitions, and when it happens it's very slight--and usually caused by the bullet hitting major shoulder bone, like that on a Cape buffalo or similar-sized animal. The folks at Nosler tell me the rear of the jacket is carefully tapered to prevent such bulging near the partition, the result of much experimentation over the past 70-some years.

I've taken dozens of animals, deer and elk, with various caliber partitions and have never seen that before. I have only recovered four however with the front part of the partition partially smeared off, 60-70% retention. Curious regarding Nosler's impression.