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Very Hot Topic (More than 25 Replies) Bullet Designs and Specs (Read 53796 times)
frnkeore
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Re: Bullet Designs and Specs
Reply #15 - May 2nd, 2013 at 1:35am
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Even more
  

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Re: Bullet Designs and Specs
Reply #16 - May 2nd, 2013 at 1:38am
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« Last Edit: Mar 16th, 2015 at 2:49pm by frnkeore »  

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Re: Bullet Designs and Specs
Reply #17 - May 4th, 2013 at 9:51pm
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Some more custom bullets
« Last Edit: Aug 2nd, 2015 at 10:04pm by frnkeore »  

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Re: Bullet Designs and Specs
Reply #18 - Jun 1st, 2013 at 4:54pm
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J Louis wrote on Apr 30th, 2013 at 6:44pm:
Without the use of a sofisticated and state of the art ballistics system it would be next to impossible to verfy real life BC's. I was fortunate to be able to do so last Thursday and it was a real eye opener. The results were not close to any of those guess and by golly computor programs offered on the net, including the bullet design software Frank has shared and that comment is not meant to be offensive, just real comparative results from the same program.


So far my program has shown it's self to be very conservative. I talked to Barry and he had results for my borrowed 33 cal Ron Long bullet that was shot in the Modesto match by it's owner. The program predicted a BC of .395 and in actual firing at 200 yards the BC was .44. With another less areodynamic bullet my program predicted a BC of .282 and that bullets actual 200 yard BC was .32 and change. So, it maybe inaccurate but, in the direction at I preffer Smiley

Frank
  

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frnkeore
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Re: Bullet Designs and Specs
Reply #19 - Jun 1st, 2013 at 5:32pm
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Here are a few more, The last bullet down is the one I just ordered from Brooks.

« Last Edit: Aug 20th, 2013 at 11:24am by frnkeore »  

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Re: Bullet Designs and Specs
Reply #20 - Jul 25th, 2013 at 6:52pm
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Three more molds.

  

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Re: Bullet Designs and Specs
Reply #21 - Jul 25th, 2013 at 9:41pm
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Frank, the Ideal 375166 bullet is 330gr.  The Precision program calculates it as 314gr
  

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J Louis
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Re: Bullet Designs and Specs
Reply #22 - Jul 25th, 2013 at 10:34pm
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I would not put to much faith in the program, especially the estimated BC's! They differ substantially based on ones particular elevation and density altitude. The drawings don't even include a baseline showing what the estimations where based off of that I can see by reviewing them.
« Last Edit: Jul 25th, 2013 at 10:43pm by J Louis »  
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frnkeore
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Re: Bullet Designs and Specs
Reply #23 - Jul 25th, 2013 at 10:59pm
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John,
As I stated before, to date, the bullets that have been tested at your range have resulted in higher BC's than the program computes.

John Boy,
The 375166 was already in the program when I got it. If you'd like to send me a bullet, I'd be happy to input the actual diamensions of your bullet. 

I post these bullet designs for informational purposes. It's not to just produce a BC. It's also to show the design criteria.The Ballistic Coeficent can change with the velocity. Most sharper pointed bullets will increase the BC with higher velocity and most blunt or round nose will increase with lower velocity, especially subsonic.

But, it will generally hold true that comparing bullet designs in this program to each other, the programs BC for one, will hold true for the others.

Bullets are aerodynamic devices and are nothing but a completely round wing as far as design goes. What holds true for wing design will hold true for bullet designs.

Frank
  

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Re: Bullet Designs and Specs
Reply #24 - Jul 26th, 2013 at 12:22am
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Frank the bullets tested through the system at my range were dramatically different than the same bullets tested on the East coast in regards to the average BC's. they were allot lower than mine as well as the programs. All I am trying to point out to the group is they might not actually be getting what is printed and that the odds of them doing so would more than likely be against them. Even worse would be for them to start telling everyone in their group as well as others how extremely high their average BC's are while not actually knowing what they really are of which is like selling a bad bag of goods unknowingly.
  
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frnkeore
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Re: Bullet Designs and Specs
Reply #25 - Jul 26th, 2013 at 1:06am
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John,
It's the design of the bullet that creates the BC. It doesn't matter where it is shot, what matters is the design. The BC will be lower or higher on the East coast as well as the West coast, in relation to each other, based on the design.

This isn't just for BC that this information is being posted. There was a question asked resently about bands and lube grooves. If you study the successfull bullet designs, you will be able to determine a type that will work for your application. It's more about how to make informed decisions, based on what works.

Frank
« Last Edit: Aug 20th, 2013 at 11:22am by frnkeore »  

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Re: Bullet Designs and Specslso I suspect
Reply #26 - Jul 26th, 2013 at 3:40am
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Frank & John-
A bullet does NOT change its BC with velocity. The bullet is not changing as it travels through the air. Its a mathematical trick you are observing. Measuring a BC at a particular velocity forces the theoretical drag to fit the drag function at that velocity. Just because you have forced the measured and theoretical drag curve functions to fit at one velocity doesn't mean that they will fit at other velocities. The drag function used for sporting ammo is "G1", while not perfect it is the most meaningful way of comparing projectile performance. Sometimes we try to hammer a square peg into a round hole and find we only have a tight fit in the corners. Bullets tested at 200 yards vs 100 yards can vary significantly, aside from the fore mentioned, BC's at 200 yards tend be more accurate since the bullet has been stabilized for a greater percent of its flight. The ballistic data observed on the East Coast was developed at 200 yards and at an altitude of 2000 ft. Also I suspect that air density may play a role in the time required to allow a bullet to stabilize. If air density has an effect on how rapidly a bullet stabilizes it is not computed into the standard atmospheric condition. I have done ballistic testing for over 12 years and rarely have seen the same bullet have the same BC day after day, just don't happen. Finally BC's have nothing to do with accuracy, only wind drift and target energy considerations. NUF SED 
  

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frnkeore
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Re: Bullet Designs and Specs
Reply #27 - Aug 19th, 2013 at 4:56pm
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I bought a couple more mold and I'll post two more Lyman's.

The last one is a modified nose version of the other 33, increasing the length to 1.245 and reducing the meplat to .060.
« Last Edit: Mar 16th, 2015 at 2:44pm by frnkeore »  

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Re: Bullet Designs and Specs
Reply #28 - Aug 20th, 2013 at 9:57am
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The forum should consider making a sticky of this thread. Frank has put in a lot of work and there is a tremendous amount of good information for reference. JMHO.
Chuck
  
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frnkeore
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Re: Bullet Designs and Specs
Reply #29 - Aug 8th, 2014 at 5:16pm
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Well, it's been almost a year since I last posted bullet designs I've bought a few molds since then so I though I'd post a few more designs.

First up is a Paul Jones mold that I just got, it was made for German Schuetzens. It casts .3165 in 22/1 but, this program rounds up so, it calls it a .317 dia. Since it is cylindrical, I assume it was ment to be shot from a case but, I'll BS it.

If there are any other PJ molds out there simular to this one, please contact me.

The next two are 30 cals, the NEI I've used BSed in my 32/35 and my wifes 32/20 it shoots just about as well as my Ron Long molds but the BC is a bit less.

I haven't shot the 311365 yet but, I'll try it in a 30/40 and '06 and then when I get my RKS mounted on my Hoch.

Frank

PS
I've added my new 319201 to this post.

PSS
I believe my mold had the cherry droped in .025 short. I added to the base band until I got the advertized 184 gr bullet so, I've mark that drawing as "original".
« Last Edit: Mar 16th, 2015 at 8:32pm by frnkeore »  

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