This seems to go in one ear and out the other with him. He has a learning disorder.
Aerospike 300 BLK 146 Lulu adventure begins
- Thread starter dellet
- Start date
dellet
Gold $$ Contributor
So today was a pooch screw.
Arrived at the range, I’d missed an email. County has Stage 2 fire restrictions, range closed.
Wanted to salvage what I could for information gathering at home.
I posted earlier that I had trouble measuring the bullet because of the spike. Seems all the trouble was not on the spike.
COL had a .004” spread
CTBO same .004” spread.
At least it’s consistent, seated with a Wilson inline die, arbor press with pressure gauge.
Set up a bullet profile in Quickload and it was surprisingly accurate. Goal and Predicted velocity of 1775, actual average of 5 shots was 1762 with 14 ES, 6.8 SD.
Nothing worth talking about as far as accuracy, picnic table, bipod, unsupported rear, three shots yielded more or less MOA at 75 yards. 8” barrel. Not worried about that now. This rifle not exactly built for bench matches.
Out of curiosity two rounds into gel to capture a bullet. I wondered how the spike and base were effected. Best I can tell, based on multiple measurements before and after, the spike lost .002-3”. That would fall within the margin of error of measurements, but longest long and shortest short were both shorter after firing.
Looks like it flattened out some.
Before and after
For what it’s worth, here’s the profile. You can still see the rolling marks, where the chuck jaw clamped down and such. Good news is inspire of all that, the bore sealed, you can see where there was some seepage at the lands, but actually this is pretty good. Quickload estimate at 56,500 psi.
All I have for today, somewhat out of business until it rains or get on a privately owned range. We’ll see how it goes.
Arrived at the range, I’d missed an email. County has Stage 2 fire restrictions, range closed.
Wanted to salvage what I could for information gathering at home.
I posted earlier that I had trouble measuring the bullet because of the spike. Seems all the trouble was not on the spike.
COL had a .004” spread
CTBO same .004” spread.
At least it’s consistent, seated with a Wilson inline die, arbor press with pressure gauge.
Set up a bullet profile in Quickload and it was surprisingly accurate. Goal and Predicted velocity of 1775, actual average of 5 shots was 1762 with 14 ES, 6.8 SD.
Nothing worth talking about as far as accuracy, picnic table, bipod, unsupported rear, three shots yielded more or less MOA at 75 yards. 8” barrel. Not worried about that now. This rifle not exactly built for bench matches.
Out of curiosity two rounds into gel to capture a bullet. I wondered how the spike and base were effected. Best I can tell, based on multiple measurements before and after, the spike lost .002-3”. That would fall within the margin of error of measurements, but longest long and shortest short were both shorter after firing.
Looks like it flattened out some.
Before and after
For what it’s worth, here’s the profile. You can still see the rolling marks, where the chuck jaw clamped down and such. Good news is inspire of all that, the bore sealed, you can see where there was some seepage at the lands, but actually this is pretty good. Quickload estimate at 56,500 psi.
All I have for today, somewhat out of business until it rains or get on a privately owned range. We’ll see how it goes.
Any sign of soot or carbon on the neck of the case out of the normal?
dellet
Gold $$ Contributor
No the neck sealed fine, considering it’s a gas gun, it’s always dirty.
The pattern on your bullet was a bit odd, but nothing exiting. What it does show is the imperfections. How much they matter is debatable.
This more normal
The bearing surface is very short on your bullet, almost seems parabolic. Might be part of it.
Here’s a bullet severely out of round.
One that shed it’s jacket at 950fps
Powder coated hard cast that hopefully would stand up to near full power loads. “See where it fails” I was asked.
note the bare one jumped the rifling all together.
Wasn’t kidding much when I said I brake diamonds
Yeah, I would rather invest length in the ogive and aerospike. I only use 0.7 calibers on these. I could probably extend the bearing surface a "bit" but I will have to eventually lose some nose or tail if it has to be longer. I will start looking at shorter nose designs that I have on file.No the neck sealed fine, considering it’s a gas gun, it’s always dirty.
View attachment 1575901
The pattern on your bullet was a bit odd, but nothing exiting. What it does show is the imperfections. How much they matter is debatable.
This more normal
View attachment 1575909
The bearing surface is very short on your bullet, almost seems parabolic. Might be part of it.
View attachment 1575922
Here’s a bullet severely out of round.
View attachment 1575923
One that shed it’s jacket at 950fps
View attachment 1575933
Powder coated hard cast that hopefully would stand up to near full power loads. “See where it fails” I was asked.
View attachment 1575943
note the bare one jumped the rifling all together.
Wasn’t kidding much when I said I brake diamonds
dellet
Gold $$ Contributor
I wouldn’t do any changes until you get some results back. Maybe tighten up the tolerances.
I keep going back to bearing surface because that’s what supports the bullet. But it also seems to be the area that is least consistent. That’s why I was checking parallel. Length is a bit hard to measure, but I get almost a .020” difference. Not sure what kind of a diameter difference might cause that. But I can’t get anything over .200”.
For a 300 BLK everything over about 2.25” is longer than the neck, so you can’t gain much.
I honestly don't see how the bearing surface can vary too much. Maybe if the stock slips in the collet? If that was the case I would expect the overall length to vary. The CNC is very accurate.
dellet
Gold $$ Contributor
That’s why I questioned my tools and the diameter. Using a .307” hole, the measurement should be long, not short.
Now that you have an idea of the extreme spread in dimensions of the bullets you might be able gin up a Monte Carlo study using the ballistics sim setup you have built to see how the effects of the differences in dimension effect the ballistics/trajectory. Well done, the MC study might shed some light on what measurements we should focus on when sorting or manufacturing bullets. It is a shame to drive to perfection on the variables that may not need it, a bang for the buck argument. This of course strong convergence between your sims and what happens when things go bang. Lacking strong convergence the results will be of no help.
I have always found MC studies to have great values when you have to start off with limited knowledge or data of the system as you can easily upgrade the model as new information comes in.
You might not be interested in this but there may well be a paper in that kind of study. Admittedly I did not do a literature search to see if the work has already been done. It would not surprise me if a similar study has been performed ay APG, if so I think access would not be an issue. My contacts in McCoy's old group are no longer current, otherwise I would probably ask them directly, it is easier.
wade
Ccrider
Gold $$ Contributor
https://forum.accurateshooter.com/threads/request-for-forum-members-please-read.4130064/
@HappyHellfire,
What is the targeted audience for your bullets?
What is your design predicted to do better than current designs?
Are you going to do 6mm bullets?
Lost River Ballistics made a solid copper .25 cal hunting bullet that was second to none. I hated to see them go out of business.
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Why so angry DJ (sorry, I’m truly sick of calling you Dr. John, so from this point forward, you are just DJ to me. Guys are literally bending over backwards to help you and you continue to shit on anyone that is even remotely critical of your work. By the way, you better review all your orders because somehow I was able to order more bullets from you to test, even though you said you wouldn’t sell me any more bullets if I was the last shooter on Earth. Well, I must be the last shooter on Earth, because me order went through. lol. Thanks for the additional bullets to review, perhaps now I can find enough with acceptable surface finish to shoot a 20 shot group.
DJ, I engage in this discussion with you because I truly want your bullets to work. Innovation drives our sport and perhaps your magic bullets can help all of shoot smaller groups. I know, I know…..save your breath and don’t worry about telling me to piss off. I remember playing football with kids like you when I was 10. As soon as you lose or someone offends your sensitive feelings, you take your ball and go home. Perhaps, you could pretend your bullets were your football when you were 10 years old and take them and head home.
Dave
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^^^^^^^ THIS SUMS UP A LOT OF PEOPLE’S FEELINGS ON THIS SITE. Normally, I don’t poke the bear so much, but when the bear shows up from his hibernation claiming superior knowledge and shitting all over anyone offering any sort of constructive criticism; I find it truly impossible to not sharpen my stick and have a few jabs at the bear.
I too will be shooting them after Nationals. Tyler, come find me at Nationals (Dave Monette & Marisa Tundo), we can only shoot the 600 yard matches because my niece’s wedding is on August 17th.
Dave
Someone said this thread was like watching a train wreck and you can’t stop watching.
I figure I may as well stay for the Explosion now.
I figure I may as well stay for the Explosion now.
This thread has been easier on the eyes since using the ignore feature.Someone said this thread was like watching a train wreck and you can’t stop watching.
I figure I may as well stay for the Explosion now.
Dellet.....How tight, and long of a throat does your chamber have ?? One
of my main concerns is the actual bearing length on those bullets. It's too
short in my opinion. Next question, considering the rifle used, how tight
of an interference fit did you use ?? The more I look at the design, and
how far the bullet will seat into the powder column, this design may only
lend itself to larger capacity cases, something like a 6.5-284, or longer
cases like a 280AI.......
And please......shoot a 5 shot group at 100 yards. And no cherry picking !! LOL
Carry on .......
I'm really just beginning with these bullets and don't know the best market. When fired around Mach 2 (2200 fps) they just have lower drag (higher BC) than a similar weight bullet. When fired from a full speed Mach 3 (3300 fps) they fly like regular boat tails until the slow down to the aerospike "engages" and the drag is much lower.
I only sell these for others after I shoot them and make sure they are safe. I don't have a 6mm gun yet but it sounds like I need to get one.
brokeasajoke
Silver $$ Contributor
So theoretically one might be able to stay supersonic longer with a smaller capacity case verses having to step on the gas with a larger case cartridge to stay supersonic at extended range? That is aerospike vs standard BT in the same case.
dellet
Gold $$ Contributor
This is why I spent a lot of time before really shooting one, and all the photos so other could see and hopefully make reasonable comments, questions.
I know it’s a pain, but single out my posts for this thread and look at the photos in the chamber gauge, that is a standard chamber cut to absolute minimum spec. My chamber only differs at the neck, it’s tighter. Gives a little more shoulder.
The rifles gas and buffer system is tuned so that I could neck size only, full power loads 3 times before needing a full length resize. Not that I do that, it’s just a way to measure performance, but my brass lasts a long time. Less rifle and scope shift also. I can generally spot for myself, see bullet impacts, less dispersion on double taps. It cycles very softly when the gas block is set for accuracy. With the right bullet, 1/2 -3/4 MOA capable.
“Right bullet” is not a joke in this cartridge, part of my continual rant in this thread.
If you were referring to neck tension, these were .003”. Loaded single feed.
Boat tail length is an issue, but not a deal killer. Roughly .400”. So depending on your sense of humor, you end up with .5-600” of bullet into a case that measures 1.180” Flash hole to neck rim. Half the case volume.
Good news is the cartridge is efficient and uses pistol powders. Yesterday’s load was 16.5 of 296. The base of the bullet was .040” off the powder column loaded at 2.170”, leaves about .105” bearing surface in the neck. Not much for an auto loader. Quickload estimate of pressure roughly 56,500 psi, over SAAMI, I don’t get too excited until over 60K.
Problem is the jump. This bullet jams .060”-080” after the bullet leaves the case. So my jump was about .170”. Really can’t shorten that much, although I could get it up to close to .300” if I tried hard. That much jump might make Mr Weatherby raise an eyebrow.
It’s not the first bullet that falls out of the case in this cartridge, so it’s does have hope.
My goal is not supreme accuracy with his bullet, just enough to prove if the drop is significantly less than something like a Hornady 150 SST. That will be a tough goal to reach, shooting under 500 yards. The drop chart included with the bullets, really isn’t an improvement from some of my live fire verified results. The problem is, I never shoot a bullet of this weight this slow, but I’m trying to duplicate @HappyHellfire test velocity.
Here’s what I expect for accuracy, same setup as yesterday. 100 meters, two sighters and a shot for score after scope adjustment. 8” barrel, 6X scope. From a cold bore. Speer 150 Gold dot.
On a weather/heat delay. Range closed due to fire restrictions. As soon as possible I will get these out to 100, 200, 300 yards to verify drop.
Hope that answers the questions.
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