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Old 06-18-2012, 10:02 PM   #1
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Default Help on sighting in

I'm shooting a 223 55 gr American eagle . I'm dead on at 100 and 150 something is going horrible wrong between 150 and 200. The bullet is 8 in low and 5 in to the right at 200. What would cause such a drastic drop? Barrell is the only thing I can guess . It's amS&W 1 to 8 . It is eating me up

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Old 06-18-2012, 10:06 PM   #2
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Originally Posted by Tenderribbs
I'm shooting a 223 55 gr American eagle . I'm dead on at 100 and 150 something is going horrible wrong between 150 and 200. The bullet is 8 in low and 5 in to the right at 200. What would cause such a drastic drop? Barrell is the only thing I can guess . It's amS&W 1 to 8 . It is eating me up
Your riflings aren't quite right for your bullets. Try something lighter.
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Old 06-18-2012, 10:12 PM   #3
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Lighter then 55? I thought 55 was like the lightest?

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Old 06-18-2012, 10:17 PM   #4
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Originally Posted by Tenderribbs
Lighter then 55? I thought 55 was like the lightest?
I believe 45 grain is the lightest.
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Old 06-18-2012, 10:18 PM   #5
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You can buy any weight from 40-80 grain bullets for 223. Most of them you have to reload but it will help you.

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Old 06-18-2012, 10:27 PM   #6
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1:8 twist is pretty fast and you should, be able to stabilize bullets up to a weight of 80 grains. American Eagle isn't exactly target ammo. I'd try something in a quality 68gr match or hunting load. The 1:8 twist barrels I've used always seem to like 68 grainers.

Black Hills 68 Gr Heavy Match loads in their "blue box" reloads are usually very accurate, but kind of pricey. Federal hunting loads have worked well also, as well as Winchester Power Points in 64gr.

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Old 06-18-2012, 10:28 PM   #7
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Man I hope your right Im about ready to throw in the sleek on this Ar

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Old 06-18-2012, 10:30 PM   #8
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My bad I read 1:6 riflings. Ya heavier bullets are alot better for them grooves.

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Old 06-18-2012, 10:36 PM   #9
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Also if you zero at 50 yds, you should be about an inch and a half high at 100yds, close to 2 inches high at 150 yds, and about three quarters of an inch high at 200 yds and at 250 yds you would be at about an inch and a half low. (Using 55gr FMJ)

If you are using a carbine barrel you may see a bit more drop because of lost velocity, when compared to a 20" barrel.

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Old 06-18-2012, 11:13 PM   #10
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Quote:
Originally Posted by Marlinman View Post
My bad I read 1:6 riflings. Ya heavier bullets are alot better for them grooves.
1:6 is even faster. Most AR barrels come in 1:12, or 1:9, 1:8, 1:7, or 1:7.7. Some 1:10 twists and other odd balls out there as well. Original twist rate when the M-16 was being developed was the very slow twist rate of 1:14.
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