Are tearing/fragmenting petals unacceptable/acceptable/desirable in a hunting bullet?

[Brobee]

Hello everyone!

I have a thread going in the reloading section of the site detailing some machine turned bullets I've been working on as a lead-free alternative for use on steel at my private rifle range. An offshoot of this project is a machine turned hunting bullet design. The original objective was to replicate something along the lines of Barnes ### expansion performance. I got out to test the first batch of hunting bullets in ballistic gelatin a couple of days, and according to the original objective the projectile failed in that all 6 petals detached from the shank of the bullet. Background on this project can be read at the following thread:

http://www.canadiangunnutz.com/forum/showthread.php?t=414000

initial weight of projectile - 155gr
recovered shank weight - 125.5gr

detached petals were all symmetrical. Unfortuantely I did not save them from the initial testing as I was too dissapointed that the initial objective was not met. I am making another batch up right now though, with the intent to go back and shoot a couple more and this time do proper documentation/photography/petal recovery.

What's prompted me to post here though is some of the comments in the above referenced thread relating to the witnessed performance being a desirable feature, thus my question for you folks here in the attached poll.

Also interesting is a link referenced by a poster in the other thread:

http://forums.accuratereloading.com/eve/forums/a/tpc/f/4711043/m/2861098911/p/6

So...what do you guys think?

 

[Brobee]

And as ancedotal evidence - I shot four deer with these projectiles and my M1A this fall. 3 were "bang/flops" and one went about 55 yards before expiring. All were complete pass throughs with no evidence of bullet deflection or fragmentation; small entrance wounds and large exit wounds.

two of the four were broadside, one of which broke both close side and far side humerous, the second went in behind fron shoulder and blew through backside humerous.

The third deer was shot through the neck from a slight angle from front-on and a slightly elevated position. Bullet blew through spin, passed through top of chest cavity and then broke 3 ribs as it exited. No fragments found.

The fourth was a smaller deer shot via the texas heart shot. Bullet broke pelvis up bigtime, some damage to intestines and stomach, perforated diaphragm. minced left lung and then exited infront of left shoulder. Large exit wound. No fragments recovered however I did not look that hard.

After hunting with them I was pretty impressed....it was not until I later went and did the gelatin testing that I started feeling dissapointed, primarily because of my pre-conceived notion that 100% weight retention was important.

 

[tjhaile]

Bullet fragmentation is not necessarily a bad thing, so long as you have adequate penetration for the game you are hunting.

With high velocity rifle bullets, fragmentation can greatly increase the diameter of the wound channel as a result of the fragments passing through tissue that is stretched by temporary fragmentation. This does, of course, tend to limit penetration.

I would worry more about penetration depth and wound channel diameter as a means of measuring wound performance than retained weight.

The last picture in this post should give you an idea of what sort of wound profiles you should be trying to achieve:

http://m4carbine.net/showthread.php?t=19878

The second profile would be optimal for thin-skinned game, whereas the third one would be better for heavier game where more penetration is required.

 

[Suka]

Petals folding out, creating a spinning razorblade are a good thing; max tissue damage.
Fragmenting I think is not, even though the shrapnel will create it's own damage outside the actual bullets path.
A bullet that fragments easily may simply not penetrate a sizeable bone(even a leg bone just S of the scapula, depending on bullet and impact velocity)

I think the ideal hunting bullet (for game in AB anyway) is one that will either or both flatten out and "petal" to some extent, but retain nearly all it's mass.

 

[ben hunchak]

You'll have to excuse me as I'm just hearing of this very worthwhile project, is it possible that the material used could be just altered in it's composition slightly so as to give some "elasticity" to the metal? This is very similar to the testing i did with very hard cast bullets that would fragment when they hit hard bone at high speeds due to brittleness. I used a softer mix and added more tin and the fragmenting went away, not sure if you can alter(possibly soften) your material.IMHO

 

[tigrr]

From a deer hunter's point of view, I have used cheap win bulk bullets and top of the line Nosler bullets. The win bulk bullets totally fragmented, taking out lungs and heart in the process. The premium bullets just punched a big hole through the heart and lungs. Both went less than 40 feet. After all is said and done the deer is still a dead deer!

 

[brotherjack]

So...what do you guys think?

It really depends on the penetration depth of the petals that detached, but since I assume they didn't just fall off on impact and actually penetrated somewhat -- then I'd say that's awesome.

If you think about it -- the world renowned Nosler Partition does what it does by letting the front part of the bullet shatter into "shrapnel" which creates a wider wound channel and transfers more energy that it would otherwise, while the rear part of the bullet behind the partition holds together with a rather small "mushroomed' front and penetrates deep (through and through, hopefully) for "insurance".

The world has yet to see a lead-free alternative bullet that duplicates this style of bullet performance. You might have something hot on your hands there, is my not-so-humble opinion.

 

[tjhaile]

If you want less frangible bullets, you could try annealing them to make them less brittle.

 

[Crankbender]

If I had to choose between a TSX and a similar bullet that lost a it's petals, opened wider/pealed further down the shank I would definitely take the later of the two.

Penetration comes at the price of a small wound channel. The current TSX bullets are set up for max penetration and small wound channels. It would be nice to have an alternative bullet, one with a really really deep hollow point to let it potentially expand to nearly the base as well as loose a bit of "shrapnel" up front.


I'd say you are on to something here. Many of us think the current X bullets lack explosive damage we are used to and find the extra penetration is not worth the trade off. In fact the extra penetraion is not even used 90% of the time especially on deer.


IF I want TSX performance I would just go buy some TSX's why bother with an imitation. Offer something different and they will come.

 

[Jordan Smith]

This product is more like the GS custom, which has fragmenting petals as well, but it largely unavailable in North America.

Having the petals fragment and cause lateral damage, combined with the solid shank that continues on to penetrate deeply, seems like a winning combination to me.

 

[762nato]

Enough weight retention to accomodate penetration, massive wound channel, complete pass through for good bleeding on both sides what more could you want.

 

[Tim H]

re: fragmentation

Brobee,

I think you're really on to something here, and in my opinion the shearing off of your "petals" is a good thing.

As I'm sure you know, when a bullet strikes live tissue it creates a temporary wound cavity as well as a permanent wound cavity. Having fragments of your bullets split off creates more permanent channels, and actually distributes more of the projectile's kinetic energy into the target's tissue. The problem with a fragmenting projectile is that if it loses too much weight, it loses too much energy, and it will not have the same penetrating power, you obviously don't have this problem!

You mentioned that the recovered shank of your 155gr projectile weighed in at 125.5gr. That's MORE than enough weight to maintain acceptable penetration, and this is proven by the fact that all 4 of the deer you shot had exit wounds. A bullet that can go through both shoulder blades of a deer, or a spine & the entire chest on a diagonal does not have to worry about a lack of penetration.

So your round is penetrating succesfully, and it is accurate. What really has me interested is the fragmenting petals. You were worried that the round wasn't retaining all it's weight, but I think it's better this way. I think that as the bullet is entering an animal the petals will begin to shear off, and start to deflect along their own separate paths, creating new temporary & permanent wound channels, destroying vital tissue. The shank of the round will no longer be stable, and physics & experience tell us that as the round destabilizes it will tumble. The tumbling is a result of the round trying to move it's heaviest porition forward. The result of the tumbling will be a much larger temporary wound channel than you would get otherwise.

Of course, that's just what I THINK will happen. And even if it does occur 99% of the time, there are always exceptions to the rule. Either way, I would confidently use a .308 with that performance on moose, elk, or bear.

I'm very interested in this project, I'm tagging your other thread to follow the progress. Thanks for sharing!

Cheers!

Tim

 

[John Y Cannuck]

My experience with the early Barnes 30-30 bullets indicated to me that petals coming off was not a good idea. The petals sheared off, meaning that both entry, and exit holes were 30 cal in size.
The petals were found in the body cavity, not in the meat, so some penetration of those petals was evident.
But the bucks (3) required several shots to duplicate the performance of one shot from a traditional cup and core bullet as far as dropping the deer.
I understand that Barnes has corrected the problem, however, the experience left a bad taste. I've not gone back to try any more.

 

[Brobee]

Major update - gelatin testing comparison on annealed vs non-annealed Brobee Bullet in companion thread over in reloading forum:

http://www.canadiangunnutz.com/forum/showthread.php?t=414000

Would sincerely appreciate feedback.

Cheers,

Brobee