I'd be willing to bet that profile of the production version would look a lot like the one I shot (post #1) if the impact velocities were closer. The bullet in post #1 is from a 3490 fps impact and the bullet in post #32 is from an impact at less than 1700 fps.
153gr Apex Afterburner .308 bullet
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I'd be willing to bet that profile of the production version would look a lot like the one I shot (post #1) if the impact velocities were closer. The bullet in post #1 is from a 3490 fps impact and the bullet in post #32 is from an impact at less than 1700 fps.
Velocity difference may well explain it. There is also a media difference. But there's also a design change. I don't know how one designs for petals to shed outward (as opposed to simply shedding) and I'm curious if it has an effect on the remaining shank.
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I'm also curious why shedding petals outward became a design priority.
mcdil
Well-Known Member
Just catching up on all the posts and wanted to address the petals question and nose behavior on the low velocity test question.
As far as the petals are concerned, there isn't a huge difference from proto to production. Basically, the petals in the proto will stay in the same trauma trail as the shank, making the trauma larger, no doubt, but still one wound. When they radiate away from center, and it's a gentle angle, they eventually separate from the main wound channel and create their own separate wound channel. Both situations create a lot of trauma.
As far as the nose not having the clean, flat shape, that's a result of pure copper at low velocity. It acts more like a cement, brittle and unpredictable, and doesn't flow like it does at higher velocities. So, the criteria for what we consider acceptable is that shot to shot, we get consistent results, clean and even petal separation, and straight penetration for the shank. At these lower impact velocities, this is what we get when we work with copper. Ours may work lower than that, but we haven't tested it there, and I'm not sure I'd be comfortable exploring lower velocities. We know that 1650 fps works consistently, and even would have been happy, less happy of course, if that velocity were a bit higher.
As far as the petals are concerned, there isn't a huge difference from proto to production. Basically, the petals in the proto will stay in the same trauma trail as the shank, making the trauma larger, no doubt, but still one wound. When they radiate away from center, and it's a gentle angle, they eventually separate from the main wound channel and create their own separate wound channel. Both situations create a lot of trauma.
As far as the nose not having the clean, flat shape, that's a result of pure copper at low velocity. It acts more like a cement, brittle and unpredictable, and doesn't flow like it does at higher velocities. So, the criteria for what we consider acceptable is that shot to shot, we get consistent results, clean and even petal separation, and straight penetration for the shank. At these lower impact velocities, this is what we get when we work with copper. Ours may work lower than that, but we haven't tested it there, and I'm not sure I'd be comfortable exploring lower velocities. We know that 1650 fps works consistently, and even would have been happy, less happy of course, if that velocity were a bit higher.
The metplat on the production design shot at 1700fps is kinda funky, I'd personally would like to see more shot at that velocity to see if there is any consistency, this is where I have seen the aluminum tip become a disadvantage
mcdil
Well-Known Member
Oh my goodness. That really does read quite comically. Not even sure how I missed that. We should probably update that soon. Sorry, no polar bear, specifically, for this bullet, lol.
wilkup
Well-Known Member
Hey Yorke, you get anything else this season with that Afterburner combination?
No, I haven't. I won't get much time to hunt for the next 8-10 weeks, so I'll probably only get out 5-6 more days during modern firearms season. I refuse to give up the muzzleloader for elk, so I'm only working with modern firearm deer seasons.
I've been mixing it up a bit though. I carried a 300 Savage loaded with the 161 Haymaker for a few days, depending on where/how I'm hunting. I had a chance at a second bear, but I spotted some cubs with her once I got in range.
I have a load for my 284 Win specialty pistol with the 117gr Afterburner that's almost dialed in. I'm getting 3190 fps from the 18" barrel using Reloader 15.5 powder. I just need to sneak out and verify drops out to 600 yards and then that load will be ready to go. I might try and use that during late modern firearm season. I'll start a new thread in the 117gr 7mm bullet once that load is ready to go.
wilkup
Well-Known Member
Looking forward to hearing about that 117gr in 7mm!
Gday mark
Still ticking on that bubble
It's close
I'm not poking the bear people just having fun with mark he has a good pill & im watching his approach to the bubble in future refinement it's not there yet & very few pills actually have it
Cheers
