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chambered221 Super Member
Joined: Aug 17, 2007 Posts: 3455 Location: Lost for good !!!
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Posted: Sun Jan 24, 2010 6:07 pm Post subject: Re: 62grn Barnes TSX |
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Joe, I ran some numbers through the JBM stability calculator !!!
From what I'm seeing the 9 twist should work. Depending on your actual velocity I could see where you could start having an issue when the temps drop below 20.
_________________ Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!
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slimjim Super Member
Joined: May 16, 2009 Posts: 8312 Location: Fort Worth TX
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Posted: Sun Jan 24, 2010 6:54 pm Post subject: Re: 62grn Barnes TSX |
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Joe, you didn't say what powder you are using. You could have a double wammy of cold day needing more bullet stability due to the denser air and cold day reducing your velocity provided by your powder. I'm using the 62gr Barnes TSX in my 1:9 twist 16 inch with Varget about .5gr under max load. I've had good groups at 100 yards. Varget is supposed to be pretty consistent with varying temperatures. Regardless, the 55gr TSX should give you higher velocity and stability
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9232 Location: south island New Zealand
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Posted: Mon Jan 25, 2010 12:12 am Post subject: Re: 62grn Barnes TSX |
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heres a thought Joe. maybe try to take the offside shoulder out. that way you get your good lung\blood vessel distruction and maybe not so much mobility after the shot. the 223 may not enuf oomph to give a exit wound but your photos show you have energy to spare. just a thought.
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slimjim Super Member
Joined: May 16, 2009 Posts: 8312 Location: Fort Worth TX
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Posted: Mon Jan 25, 2010 7:51 am Post subject: Re: 62grn Barnes TSX |
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I checked the stability factor for the two different bullets. The velocities are an estimate based off Barnes data for Varget powder and reducing for our 16" barrel. I assumed about 30 fps loss per inch. The stability of the 62gr is marginal. I estimated bullet length for the 55gr based off their 53gr TSX. Muzzle velocity changes has little impact. Drop the temp 30 degrees to 20 F and you loose almost a .1 of stability. Looks like the 53 to 55gr TSX would work better in our shorter barrels.
Caliber _ 0.224 Inches
Weight _ 62 Grains
Length _ 0.942 Inches
Twist _ 9 Inches/turn
muzzle vel _ 2700 fps
Temp _ 50 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Sg = 1.28
Caliber _ 0.224 Inches
Weight _ 55 Grains
Length _ 0.8 Inches
Twist _ 9 Inches/turn
muzzle vel _ 2900 fps
Temp _ 50 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Sg = 1.84
Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.
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shrpshtrjoe Super Red Neck Member
Joined: Jan 26, 2005 Posts: 2965 Location: Maryland
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Posted: Mon Jan 25, 2010 4:13 pm Post subject: Re: 62grn Barnes TSX |
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slimjim wrote: |
I checked the stability factor for the two different bullets. The velocities are an estimate based off Barnes data for Varget powder and reducing for our 16" barrel. I assumed about 30 fps loss per inch. The stability of the 62gr is marginal. I estimated bullet length for the 55gr based off their 53gr TSX. Muzzle velocity changes has little impact. Drop the temp 30 degrees to 20 F and you loose almost a .1 of stability. Looks like the 53 to 55gr TSX would work better in our shorter barrels.
Caliber _ 0.224 Inches
Weight _ 62 Grains
Length _ 0.942 Inches
Twist _ 9 Inches/turn
muzzle vel _ 2700 fps
Temp _ 50 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Sg = 1.28
Caliber _ 0.224 Inches
Weight _ 55 Grains
Length _ 0.8 Inches
Twist _ 9 Inches/turn
muzzle vel _ 2900 fps
Temp _ 50 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Sg = 1.84
Sg shouldn't be less than 1.4. If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel. |
Im using 25 grains of Varget. Im gonna try the 55 grain TSX and see what happens. My buddys Bushmaster is shooting the 62's ok at 100yds I guess mine dosean't like them. Thanks for the Info. Do you have a program on your computer to figure that factor out ?
Joe
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chambered221 Super Member
Joined: Aug 17, 2007 Posts: 3455 Location: Lost for good !!!
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Posted: Mon Jan 25, 2010 6:40 pm Post subject: Re: 62grn Barnes TSX |
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_________________ 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.
~George Washington |
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shrpshtrjoe Super Red Neck Member
Joined: Jan 26, 2005 Posts: 2965 Location: Maryland
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slimjim Super Member
Joined: May 16, 2009 Posts: 8312 Location: Fort Worth TX
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Posted: Mon Jan 25, 2010 7:46 pm Post subject: Re: 62grn Barnes TSX |
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Here is another source. They provide some explainations and an excel spreadsheet you can save to your computer to use at anytime.
Calculating Bullet RPM — Spin Rates and Stability
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shrpshtrjoe Super Red Neck Member
Joined: Jan 26, 2005 Posts: 2965 Location: Maryland
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Posted: Mon Jan 25, 2010 7:47 pm Post subject: Re: 62grn Barnes TSX |
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