There are similarities on the nose design between the ZA, and the Moeller offering. We both utilize versions of the Haack minimum-drag formula. He uses the L-V, and I use the L-D (for good reason).
The small hole you see on his hunt-bullets are an example of the "explosive" hollow-point variety. That nose type simply disappears upon impact (literally). Mine are a genuine controlled-expansion design, and yes, I agree they need to be capable of opening up at low velocity. The polymer tip I use has a sustained operating temperature specification of 350 degrees Farenheit, and the core is bonded in layered alloys which progressively increase expansion resistance.
The black plastic tip you may have seen on the Moeller bullet is polypropylene (milk carton plastic). They serve a strictly (limited) aerodynamic function, on a rather blint-nose configuration. It remains a fragmentation-type projectile.
It sounds like Paul and I will be treating our bores with gun juice for a while yet.
Originally Posted by noel carlson
My experience with solid projectile expansion is more an issue of controlling it, not causing it. As mentioned, a frangible bullet is easy, as solids tend to strike with explosive results with simple hollow-point construction. The Ultem tip is one of the means to controlling even expansion (in addition to BC enhancement). Gerard may be using oxygen-free copper. You can get away with a hollow point using this alloy, but it is awfully abrasive to cutting tools.
Now here's where we might get some discussion. Three types of bullets that I known of that are know for "fairly" reliable expansion, but have also been reported to have failed are the TSX/TTSX, NBT and Berger. The TSX is a hollow point copper monometal that has been reported not to open along with it's poly tipped version, the TTSX. The Nosler Ballistic Tip (poly tip) which is usually know for explosive expansion has also been reported to not expand at all. The Berger with a very small metplat-hollow point has also been reported not to open on occasion. Maybe there were handling issues with these bullets that failed? I dont know. But there seems to be enough reports to suggest a trend.
There are some bullets that I have not heard about failures which include the Nosler AB and E-Tip. The E-Tips is very new yet. So, it seems to me that tipped bullets "may" occasionally fail to open as well as some hollow pints. This is an area where GS seems to take every precaution. I have only once had an animal get away from me wounded. My first deer, I dont wanrt to ever repeat that experience. I was also huning with some freinds when a deer was put down and when we got over to other side of the coulee it was up and gone. We tracked it for a couple of miles before loosing the blood trail. I dont like those experiences. In the second experience, I cant say if it was the bullet or shot placement. In the first case it was shot placement.
Point being, Im a little skeptical of very small hollow points and tipped bullets, although I am load deveoping for some.
Last edited by MontanaRifleman; 06-22-2009 at 08:20 AM.
Interesting stuff. Hope it comes together and I can afford it when it does. Maybe by the time I need to re-barrel a 25 RUM, these patents will be taken care of and some of the technology will be ready to roll.
The Barnes alloy tends torwards the GS in terms of ductility. Your experience in comparative reliability I would speculate to be connected to differing manufacturing methods, and tolerances. I have some idea of what Gerard is doing, and I agree that it would be very surprising to see one of his hollow-points fail.
It will be some time, obviously, before this type of reporting is possible for the ZA.
You mentioned skepticism regarding small hollow-points, and polymer tips. I am definitely retaining the tip, but it may be of interest to you to know that the ZA core, while not technically hollow (it is bonded), is fairly large in diameter. The .75" deep hole is triple splined to full length in .030" relief cuts. It is equally difficult for me to imagine this failing to expand over the designed impact velocity range. Time, and experience, will tell.
Thanks for the detail which you include in your observations. It aids me in understanding field requirements.
Location: The rifle range, or archery range or behind the computer in Alaska
Re: The Solid Bullet Debate
Originally Posted by noel carlson
It is equally difficult for me to imagine this failing to expand over the designed impact velocity range.
What is your designed impact velocity range for reliable expansion? In other words what is the minimum AND maximum impact velocities?
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
From 1,400-3,300 fps the bullet will maintain a minimum caliber expansion of 1.5, and maximum 2.5, with 90%+ mass retention.
The .338 ZA hunt bullet is really a diversion however, made possible only by the increasing popularity of the 9.0-9.5" twist. Unless the entire market goes lead-free, necessitating tighter twist-rates generally, this will be my sole contribution.