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Author Topic: Velocities with carbine barrels  (Read 397 times)

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Offline jpuke

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Velocities with carbine barrels
« on: January 24, 2004, 10:25:27 AM »
I've been reloading for my Remington Model 7 (308 Win) for three years and without a chronograph I've been in the dark about my velocities until my wife got me a chronograph for christmas.  I went out today and used it for the first time and I noticed a couple of things and I was wondering if anyone else has noticed the same trends:  Heavier bullets show less velocity loss in my gun than the lighter ones.  The load data I have says that with the powder charges I use (in a 24in. barrel) a 130 gr bullet should do about 3130 fps, a 150gr around 2930, a 180gr. around 2660 and a 200gr should do about 2440.  My twenty inch barrel does 2960 with the 130, 2750 with the 150gr., 2590 with the 180gr. and 2360 with the 200.  That's a difference of 170fps with the 130gr, 180 fps with the 150gr., 70 fps with the 180 gr and only 80 with the 200gr.
Has anyone else noticed this before or are my results messed up?  I have to admit I was pleasantly suprised because the 180 gr. load also happens to be the most accurate one that I've worked up.  My guess is that the smaller powder charges used with the heavier bullets end up being more efficient, but if anyone has any input on this I'd love to hear it.
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Offline ricciardelli

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Velocities with carbine barrels
« Reply #1 on: January 24, 2004, 01:17:19 PM »
Just one little note I would liek to add here...

NEVER believe the velocities you read in reloading manuals or on factory boxes.
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Offline The Pistoleer

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Velocities with carbine barrels
« Reply #2 on: January 30, 2004, 01:14:03 PM »
jpuke, interesting observation.  I just bought a Ruger International with a 18.5"bbl.

I am leaning towards using 165 grain bullets.  I have been told that they are the best compromise in short barrels.

Pete
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Offline Blackhawk44

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Velocities with carbine barrels
« Reply #3 on: January 30, 2004, 01:27:51 PM »
One thing to remember when reading most velocities in manuals: they are usually recorded in a controlled atmosphere, from a minimum spec pressure gun.  Your velocities are just fine.  Anyone who thinks that they can tell the difference in the field between the same bullet at 2750fps and 2850fps inside almost 400 yards is truly kidding themselves.  Thousands of deer die each year inside 200 yards from 150gr bullets at 2000-2300fps.  Its called a 30-30.  We fought WWII with a 150gr at 2700fps, and won.
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Offline jhalcott

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Velocities with carbine barrels
« Reply #4 on: January 31, 2004, 09:05:07 AM »
jpuke, now take 10 each of your reloads and keep them till August.Chrono them in about 100 degree weather and see ehat that does.
 I chronoed some excellent loads in late January one year and got great results,almost what the book called for. Later that year those loads were too hot and cases were sticking,hard bolt lift,etc..I chronoed them again,same gun same loads and found out I was getting about 100 fps OVER book.I had to keep the ammo in the lunch cooler and the gun in the shade till it was all gone.   jh
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