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gelandangan Super Member
Joined: May 07, 2006 Posts: 6398 Location: Sydney Australia
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Posted: Sun Aug 04, 2013 11:31 pm Post subject: Re: What Defines Bullet Expansion? |
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slimjim wrote: |
Thanks, gelandangan. I should have thought of doing an article but there are a couple of disadvantages the biggest one being when the site software gets updated, the articles get dumped and have to be resubmitted.
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Slim,
If you have the study done as an article, it can then be read as a single continuous study.
I doubt articles are dump unless there are problem with the backup, and Dallan has been pretty good in keeping up to date with the backups.
_________________ A straight line is the shortest distance between two points.
A smile is the shortest distance between two people.
Do - Not try!
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Aug 05, 2013 5:53 am Post subject: |
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repeat
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Last edited by slimjim on Mon Aug 05, 2013 7:43 pm; edited 2 times in total |
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MacD Super Member
Joined: Apr 08, 2011 Posts: 1052 Location: Canada
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Posted: Mon Aug 05, 2013 9:54 am Post subject: Re: What Defines Bullet Expansion? |
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Slim; fasinating study. I am using Barnes TSX bullets 168 grain in my 308 hunting rounds. Muzzle velocity 2600 - 2700 if I recall correctly. I chose them primarily because they are accurate in my rifle and I needed something that would punch through the chest of a moose including the rib bones without coming apart and sending bits and pieces all over the place. The longest shot I have ever taken was about 300 paces but most shots are within 150 yards. I haven't used thr TSX on a moose yet so no personal experience to back up my thinking. Was the TSX the right choice? I also considered the TTSX and the Hornady SST. I guess my main question is how well do you think your test results carry over into the field?
_________________ La a'Blair s'math n Cairdean
(Friends are good on the day of battle) |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Aug 05, 2013 5:13 pm Post subject: Re: What Defines Bullet Expansion? |
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MacD, the TSX is a great choice for your application. It will expand better than the .277 130gr because its ogive is not as long. SST is a fragmentation bullet. The TTSX is longer with a better BC but you will give up case capacity and muzzle velocity.
The test results compare very closely withfield results. You can see the GMX recovered from an elk above. I will post some other comparisons for you.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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English Mike Super Member
Joined: Jan 08, 2007 Posts: 1709 Location: Whitehaven, Cumbria, UK
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Posted: Mon Aug 05, 2013 6:12 pm Post subject: Re: What Defines Bullet Expansion? |
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The GMX looks like it does what it's supposed to, so I might have a box to try come November.
Hopefully it'll be more consistent than the SST, which produced disappointing accuracy when we tried it a while back.
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Aug 05, 2013 6:34 pm Post subject: Re: What Defines Bullet Expansion? |
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The GMX in my rifle has been as accurate as Berger VLDs. My hunting buddy uses the GMX Superformance in his 300 Win Mag and is achieving less than 1 MOA. The GMX are fully expanded by the inside of the near-side rib cage. They don't expand quite as much as the Nosler E-Tip or Barnes in close but they are very consistent and have become the favorite for hog hunters.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Aug 05, 2013 6:36 pm Post subject: Re: What Defines Bullet Expansion? |
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Here is a comparison of 6.8mm AccuBond and TTSX bullets recovered from testing and from game.
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_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Mon Aug 05, 2013 6:52 pm Post subject: Re: What Defines Bullet Expansion? |
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Even negative performance has been correlated in testing. The .277 Berger VLDs, 130gr-150gr, have always yawed, turned 180, and penetrated tail-first in terminal performance testing. No fragmentation whatsoever. It hasn't matter if fired from a 6.8 or .270. Here is a hunter that found his 140gr VLD shot from a 6.8 on top of the snow behind a caribou he shot. The copper jacket has enough strutural integrety to remain intact upon impact. I've shot them from 100 to 500 yards and watched the bullet leave a waterjug undisturbed and leaking water. The picture belows shows the VLD yawing through the foam board that is positioned just behind the water jug.
Berger is a great company and their bullets are very accurate. The .277 VLD bullets just do not have the terminal performance I expect in a hunting bullet.
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_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Last edited by slimjim on Thu Aug 08, 2013 4:55 am; edited 1 time in total |
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Azar Member
Joined: Jan 04, 2010 Posts: 275 Location: Utah
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Posted: Tue Aug 06, 2013 3:35 pm Post subject: Re: What Defines Bullet Expansion? |
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slimjim,
You've obviously put a lot of work and effort into this.
Thanks for sharing your findings! It's quite interesting.
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Ominivision1 Super Member
Joined: Sep 20, 2010 Posts: 2984 Location: Iowa
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Posted: Tue Aug 06, 2013 3:43 pm Post subject: Re: What Defines Bullet Expansion? |
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Very interesting indeed, good work Slim.
_________________ Regards
Limitations are but boundaries created inside our minds. |
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shrpshtrjoe Super Red Neck Member
Joined: Jan 26, 2005 Posts: 2965 Location: Maryland
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Posted: Tue Aug 06, 2013 3:50 pm Post subject: Re: What Defines Bullet Expansion? |
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You do a great job documenting your tests slim . Its presented very well.. Thanks for sharing your results with the Nuts .. Good Info
_________________ "MOLON LABE"
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Wed Aug 07, 2013 3:08 am Post subject: Re: What Defines Bullet Expansion? |
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Thanks guys for taking the time to read and comment. I really enjoy the challenge of testing and trying to figure out how bullets perform.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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MacD Super Member
Joined: Apr 08, 2011 Posts: 1052 Location: Canada
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Posted: Wed Aug 07, 2013 12:59 pm Post subject: Re: What Defines Bullet Expansion? |
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Thanks again Slim. Looks like my TSX loads will work out fine. No moose license this year but I may go for a spring bear.
_________________ La a'Blair s'math n Cairdean
(Friends are good on the day of battle) |
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Vince Site Admin
Joined: May 25, 2005 Posts: 15715 Location: Brisbane AUSTRALIA
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Thu Aug 08, 2013 1:55 pm Post subject: Re: What Defines Bullet Expansion? |
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Vince wrote: |
Whilst the calibre is different to what I shoot, the data should apply to my rifle in . 243 Win. |
Thanks, Vince. You are right, I have done most of my testing with .277/6.8mm but I also have tested plenty of .223/5.56mm (which is why I switched to a 6.8mm) and some limited .308 that my hunting buddy was using for our elk hunt. Some simple logic applies.
- Like bullets of different calibers usually perform the same but the larger caliber will have larger expansion.
- Now that I realize that energy defines bullet expansion, I know why a 165gr GMX shot from a .300 Win Mag expands more at 500 yards than a 130gr GMX shot from a .270 Win even though their velocities are close to being the same (larger caliber plus more energy).
- What may surprise you is that the .270 will out penetrate the .300 Win Mag with like-construction bullets. A bullet with more expansion will penetrate less than a bullet with less expansion, sometimes even when it has less kinetic energy.
- I've also noted that almost all bullets penetrate deeper at longer ranges because their expansion decreases faster than kinetic energy. For a bullet to penetrate less at longer ranges, it has to very consisten expansion across its velocity range.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Last edited by slimjim on Fri Aug 09, 2013 5:06 pm; edited 2 times in total |
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