Pennsylvania Firearm Owners Association
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  1. #1
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    Default I had no idea how similar 223 and 308 bullet drop was!

    https://www.snipercountry.com/308-vs-223/

    I ordered a Burris mtac 1.5x6x42 with the ballistic cq reticle and was trying to verify that the model was the one meant for 5.56 and not 7.62.

    Turns out, they are one and the same. This kind of opens up scope possibilities knowing that something with bdc for 308 will be fairly close with 5.56 (or the other way around) or at least with the same degree of error as different length barrel, ammunition, etc.

    Also, it is my first illuminated scope. I've been living my life wrong!

    -Zach

  2. #2
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    That is interesting.
    Gender confusion is a mental illness

  3. #3
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Quote Originally Posted by zachomega View Post
    https://www.snipercountry.com/308-vs-223/

    I ordered a Burris mtac 1.5x6x42 with the ballistic cq reticle and was trying to verify that the model was the one meant for 5.56 and not 7.62.

    Turns out, they are one and the same. This kind of opens up scope possibilities knowing that something with bdc for 308 will be fairly close with 5.56 (or the other way around) or at least with the same degree of error as different length barrel, ammunition, etc.

    Also, it is my first illuminated scope. I've been living my life wrong!

    -Zach
    It's even closer with 7mm-08. I learned that one when I was looking at scopes for my deer rifle.

  4. #4
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Do you mean that they are similar only for the "standard" rounds, i.e., M193/M855 for 5.56mm NATO vs M80 for 7.62mm NATO? Or are they, more or less, compatible across the whole spctrum of bullet weights?

  5. #5
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Quote Originally Posted by Fortytwo View Post
    Do you mean that they are similar only for the "standard" rounds, i.e., M193/M855 for 5.56mm NATO vs M80 for 7.62mm NATO? Or are they, more or less, compatible across the whole spctrum of bullet weights?




    The article has averages and methodology.

    -Zach

  6. #6
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    The article is to "chopped up" and doesn't provide the necessary data to compare apples to apples. I can't tell what weight bullet was fired at what velocity to arrive at their numbers.

    My ballistic program reflects the bullet drops and energy from bullets that Ive shot over my chronograph.

    My .308 shooting a 150gr. Hornady SST with a MV of 2,677 shows a drop at 300yds of 15.19" and energy of 1,421-ft\lbs.
    My .223 shooting a 68gr. Hornady BTHP Match with a MV of 2,660 shows a drop at 300yds of 8.06" and energy of 774-ft\lbs.

    And FWIW my 6.5x55 Swede (modern action) shooting a 140gr. Hornady ELD with a MV of 2,731 shows a drop at 300yds of 13.2" and energy of 1,641-ft-lbs.

    BTW, my .308 load can be bumped up to shoot a higher velocity.....but at that velocity with that bullet it will shoot one ragged hole at 100-yds. The faster I pushed it the bigger the groups got.

  7. #7
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Quote Originally Posted by zachomega View Post
    https://www.snipercountry.com/308-vs-223/

    I ordered a Burris mtac 1.5x6x42 with the ballistic cq reticle and was trying to verify that the model was the one meant for 5.56 and not 7.62.

    Turns out, they are one and the same. This kind of opens up scope possibilities knowing that something with bdc for 308 will be fairly close with 5.56 (or the other way around) or at least with the same degree of error as different length barrel, ammunition, etc.

    Also, it is my first illuminated scope. I've been living my life wrong!

    -Zach
    The bullet mass has no effect on drop. Gravity doesn't care about mass. What matters is muzzle velocity and aerodynamic characteristics. The 5.56 NATO round is a little zippier than the 7.62, has less drag and shoots a bit flatter, but there is still a huge reduction in effective range against critters because of the huge difference in energy (F=MA). Windage is a different deal and the 7.62 wins that contest.

    These scopes are made for hunting and 3 gun, and the drop reticles are close enough. For more precise shooting (especially at longer distances), I use a Mildot reticle and Ballistic AE on my phone plus real DOPE, which is on a card attached to my stock.
    Boy, I say boy, you're reaching the limits of my medication!

  8. #8
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Quote Originally Posted by Gripsafety View Post
    The bullet mass has no effect on drop. Gravity doesn't care about mass. What matters is muzzle velocity and aerodynamic characteristics. The 5.56 NATO round is a little zippier than the 7.62, has less drag and shoots a bit flatter, but there is still a huge reduction in effective range against critters because of the huge difference in energy (F=MA). Windage is a different deal and the 7.62 wins that contest.

    These scopes are made for hunting and 3 gun, and the drop reticles are close enough. For more precise shooting (especially at longer distances), I use a Mildot reticle and Ballistic AE on my phone plus real DOPE, which is on a card attached to my stock.
    No doubt, any bdc reticle is for the close enough is good enough camp.

    I don't think anybody would ever claim that bdc is for precision though.

    -Zach

  9. #9
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Bullet drop is calculated by the muzzle velocity and the ballistic coefficient of the bullet. That is all you need to know. Since the 223 starts out about 300 fps faster than a 308 the trajectory curves will never match up exactly.

    But it is close enough for hunting under 250 yards. You are not going to miss the deer.

  10. #10
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    Default Re: I had no idea how similar 223 and 308 bullet drop was!

    Quote Originally Posted by Delkal View Post
    Bullet drop is calculated by the muzzle velocity and the ballistic coefficient of the bullet. That is all you need to know. Since the 223 starts out about 300 fps faster than a 308 the trajectory curves will never match up exactly.

    But it is close enough for hunting under 250 yards. You are not going to miss the deer.
    As my friend used to say (a long time ago) when we missed by half a foot at 300 yds with 7.62x39 with iron sights in the high desert, "If it was a [let's say "bad guy"], it'd be dead."
    Boy, I say boy, you're reaching the limits of my medication!

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