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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Wed Oct 22, 2014 8:17 am Post subject: Re: 300 Win Mag Questions? |
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chambered221 wrote: |
Again I'll ask...... how are you determining down range velocities ??? |
Sorry, I missed that one chambered. I use a chrony 15' in front of the muzzle and use BC to determine impact velocity. I've placed my chrony at 250 yards before and shot through it to check BCs but without the velocity at the muzzle its only a ball park check if you use an average mv. I haven't seen gelatin tests done at 250 to 500 yards. To get the impact velocities (actually kinetic energy) to match, I shoot the the 6.8 from 25 to 200 yards and the .270 from 300 to 500 yards. I've also been doing it with the same rifle by using Trailboss at 25 yards and comparing results to bullets shoot with regular powder at 400 to 500 yards. I have a test set-up with the new Accubond Long Range to see what the difference is.
Your explaination of bullet exploding is correct, but Elvis may be correct also. It will take me a while but I will set-up some tests to see if I can measure the differences in monolithic bullets.
Your explaination of once the bullet has enough stability to expand and stay stable in the wound channel, twist doesn't make a difference is supported by some bullets like the .223 62 TTSX. But I've seen other bullets like the .223 55gr GMX and .277 130 TTSX that are functioning like Evis is suggesting. I just haven't shot enough to get a sample size to definitively make a conclusion yet.
If my wife ever figured out how much I spend to do all these tests, I would be in hot water. I've told her I'm going to write a book about it which is why I'm using my buddies .300 Win Mag.
_________________ "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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Ominivision1 Super Member
Joined: Sep 20, 2010 Posts: 2984 Location: Iowa
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Posted: Wed Oct 22, 2014 2:43 pm Post subject: Re: 300 Win Mag Questions? |
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Bushmaster wrote: |
I've been reading all of these posts. To some point I have to agree to disagree.
Due to the distance traveled by a bullet in one revolution I can not see where there is enough centrifical force to effect bullet expantion. Especially when it has entered the body. The bullet is slowed so fast that centrifical force would be negligable. Expantion is more of a hydraulic force then centrifical. Centrifical force may be a factor, but of little or no effect.
Just my opinion (feeling) on the subject |
Bingo, I think to many people are astonished by the "bullet rpm"
Here is some math.
100 yards times 36 inches is 3600 inches.
one turn in 10" twist barrel-"3600 divided by 10 = 360 bullet revolutions per 100 yards".
a 1/9 twist-400 complete rotations of the bullet out to 100 yards.
a 1/7 twist--514 revolutions of the bullet out to 100 yards.
So by the time the bullet using a 1-10 twist reaches 1000 yards, it will have rotated 3600 times.
According to the Speer manual a bullet with MV of 3500fps is spinning at 330,000rpm. This is enough centripetal (not to be confused with centrifugal force) to strip the jackets off of some thin jacketed varmint bullets.
We did have a thread on this a few years back but I'll be darned if I can find it.
_________________ Regards
Limitations are but boundaries created inside our minds. |
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PaulS Super Member
Joined: Feb 18, 2006 Posts: 4330 Location: South-Eastern Washington - the State
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Posted: Wed Oct 22, 2014 7:12 pm Post subject: Re: 300 Win Mag Questions? |
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The bullet upset on impact occurs only if it is minimaly stable in flight. Leave those close tollerances for the guys shooting paper at 1000 yards. As long as the construction of the bullet allows the more spin it has the more stable it will be on impact at "normal" hunting ranges (25 - 300 yards).
A tumbling bullet produces a nasty wound cavity but usually not a big exit hole. Typical expansions is shown to occur between 4 and 14 inches of penetration in ballistics gel under controlled conditions. An "over-stabilized" bullet will perform better on game than a marginally stabilized bullet. The stability of a bullet is usually computed for the projectile in flight through the air. If you are minimally stabilizing a bullet at 80F then it will tumble when shot at 40F.
From a hunter's point of view faster is better when it comes to twist rate.
_________________ Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Wed Oct 22, 2014 7:39 pm Post subject: Re: 300 Win Mag Questions? |
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PaulS wrote: |
Typical expansions is shown to occur between 4 and 14 inches of penetration in ballistics gel under controlled conditions. |
I can believe 4-14 inches is the depth at which the temperary wound channel effect is generated. But if bullets don't expand (shorten in length and increase in diameter) in the first couple inches, they tumble and either fragment or stay together and penetrate tail first. The entrance wound on the inside of an elks rib cage has been the same size as the exit wound with GMX bullets. I place foam at the begining of the bullet traps to have a record of what the bullet epxnsion was or if the bullet yawed. Thes are about 6" after impact.
Windcheter came out and stated their monolithic bullets penetrate then expand which is just marketing hype. If they penetrate without immediately expanding, they tumble.
Agreed, more spin is better for hunting and helps keep the terminal trajectory interminal to the game on course.
_________________ "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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chambered221 Super Member
Joined: Aug 17, 2007 Posts: 3455 Location: Lost for good !!!
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Posted: Thu Oct 23, 2014 7:01 am Post subject: Re: 300 Win Mag Questions? |
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[Post in reference to expansion difference between 6.8 and .270]
Slim, I'd be willing to bet ya a beer or three of Vince s that your impact velocities are not the same !!!
Perhaps taking average velocities at muzzle, 100 yards and 200 yards could be a better way of checking this. 3 shots each distance should give a good ballpark idea if shot deviation is consistent enough. That would also give you better data to confirm BC's using a online calculator.
_________________ Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!
A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Thu Oct 23, 2014 7:48 am Post subject: Re: 300 Win Mag Questions? |
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chambered, the velocities at impact are not exactly the same but I plot their kinetic energy levels vs expansion so I'm comparing lines defined by multiple points. I have found averaging velocities does not work. I take the velocity of that specific bullet and run it through the calculator. It is not uncommon for a load to have a 100 fps difference between high and low. I keep track of the average but only use it on the rare occasion my chrony doesn't record it. Here is an example of a plot. Not listed there is the 140 TSX which exactly matched the 110 TSX expanion curve. Both these bullets have Barnes' new expansion cavity.
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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: Fri Oct 24, 2014 2:14 pm Post subject: Re: 300 Win Mag Questions? |
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Ok, back to the original issue. The SAAMI COAL for the 300 WM is 3.340" which puts the ogive of today's monolithic bullets close or at the mouth of the case. My buddy's rifle is a S&W that I think was made in the 80's. Took some measurements. Here's what I found.
Good news the magazine max dimension is 3.580".
Then I started measuring distance to the lands for the following bullets.
150 TSX
165 & 168 TTSX
150 GMX
150 & 168 E-Tip
... and got another surprise!
Only two bullets touched the land with the minimum amount of bullet shank in the neck - 165 TTSX and 168 E-Tip.
168 E-tip was 3.600 to the lands so will load 3.350" or shorter COAL which fits the magazine well and still ejects without having to pull the bolt. Didn't take a measurement on the 165 TTSX as will seat the first band inside the case mouth and have plenty of room in the mag well.
Surprise, Surprize. Now I have to go see how well I can get the bullets to group.
_________________ "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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hunterjoe21 Super Member
Joined: Mar 30, 2007 Posts: 1486 Location: Miles City, Montana
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Posted: Sat Nov 22, 2014 8:36 pm Post subject: Re: 300 Win Mag Questions? |
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Any updates slim?
_________________ My 1911 is more effective than your 911. |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Sun Nov 23, 2014 12:10 am Post subject: Re: 300 Win Mag Questions? |
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hunterjoe21 wrote: |
Any updates slim? |
I finished loading this afternoon. I have a series of loads from min to moderate to max using MagPro as well as 30gr of TrailBoss to test minimum kinetic energy for expansion. I plan on going to the range on Friday with the bullets below. I decided to add the 130gr TTSX It has the same nose/ogive as the 150 and 165 TTSX so want to give it a try. It gets 3000+ fps from a .308 and around 3500 fps out of the 300 Win Mag (that will leave a vapor trail).
150 TSX
130, 165 & 168 TTSX
150 & 165 GMX
150 & 168 E-Tip
_________________ "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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hunterjoe21 Super Member
Joined: Mar 30, 2007 Posts: 1486 Location: Miles City, Montana
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Posted: Sat Jan 03, 2015 10:02 pm Post subject: Re: 300 Win Mag Questions? |
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Didja ever make it to the range?
_________________ My 1911 is more effective than your 911. |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Sat Jan 03, 2015 10:25 pm Post subject: Re: 300 Win Mag Questions? |
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Wow, that was over a month ago. Thanks for asking. My shooting buddy with the .300 Win Mag ended up have a job pop-up the last 3 times we coordinated some range time so I have no updates. It may be another 30 days before I can get back out with him.
_________________ "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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hunterjoe21 Super Member
Joined: Mar 30, 2007 Posts: 1486 Location: Miles City, Montana
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Posted: Sun Sep 27, 2015 7:31 pm Post subject: Re: 300 Win Mag Questions? |
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Slim,
Any updates?
I'm starting to acquire components to develop an elk load for my new Kimber 300 win mag, but still haven't decided between Nosler Partitions and Barnes TTSX.
_________________ My 1911 is more effective than your 911. |
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9239 Location: south island New Zealand
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Posted: Sun Sep 27, 2015 8:03 pm Post subject: Re: 300 Win Mag Questions? |
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jeeez hunterjoe........what a hard choice
from what I know and have seen the partition would be a very hard one to beat however if you are maybe going to end up with 50 yard shot the TTSX could well give you less meat damage but still have power to spare...if range is over 300 again the partition would/should be better option.
_________________ You shot it You pluck it !
Them who eats the most duck eats the most feathers! |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8314 Location: Fort Worth TX
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Posted: Sun Sep 27, 2015 8:35 pm Post subject: Re: 300 Win Mag Questions? |
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Elvis, is that a quaker on the throne!?!?
HJ, hard to argue with Elvis advise. I like the AccuBonds in my 6.8mm but they retain their weight much better than other Accubonds. Typically, you will see an AB in a .270, 7mm, or .308 retain between 50 and 60% of their weight. Barnes and GMX are good monolithic options and will function past 500 yards in a .300 WinMag. Its all about what your rifle shoots best and you are most confident with. Avoid the AccuBond Long Range. It super soft and fragments more lead than any bullet I've seen.
_________________ "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: Sun Sep 27, 2015 8:36 pm Post subject: Re: 300 Win Mag Questions? |
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Wait a minute!?!? My last post was from January!! Boy as this year gone by fast. Time is slipping away.
Really, Elvis? A duck on a toilet?
_________________ "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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