Zero at 15 yards

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    One ragged donut hole
    Nov 13, 2009
    608
    MoCo
    So I got some SBRs and really short things with stocks as the home defense weapons in my little suburban mixed use neighborhood thing. Now I'm thinking I should zero them for 15 yards. Am curious if anyone has a great idea why I should not do this??? I have two reasons for doing this.

    Measuring distances in my house, it's very hard to get a line of sight that is more than 15 yards. Which is amazing, because when I go to the outdoor range and hike 100 yards to put up targets, it doesn't seem all that far. But anyway, I guess the house is short.

    Second reason, if you shoot anything that is more than 15 yards from you, you are probably going to prison. Exception, you are a now a Rooftop Korean doing what you need to do because it is total chaos out there. But that was 1992, nearly 30 years ago. And in this climate, in Maryland, even showing the weapon will get you some serious heat. If you are not LEO, and you shoot at something 50 yards away from you in Maryland, you aren't going back to your job. So maybe that's because society has collapsed, but that doesn't seem to be likely at this point, even in the most bearish scenario. If you shoot someone who is OUTSIDE of your house, while you are inside, that's the end of your normal life.

    If I fire the weapon indoors, probably at 15 yards or less. I used a rangefinder to look around the neighborhood, and still only around 50 yards or so to get to points of interest. So if I need to go out to 50 yards, for this subsonic 300 BO load, I would be coming up 4 in at 50 yards with a 15 yard zero. That seems like a minor inconvenience for being at zero over target for 99% of the use cases in this suburban area.

    If I lived on actual land, with space, I could maybe see a 50 yard zero, if I needed to credibly deter some threat on the perimeter that was on the way in.

    So in a suburban sort of neighborhood, not living in the woods or the plains etc, is there some reason why at 15 yard zero would be bad on a defense SBR?
     

    babalou

    Ultimate Member
    MDS Supporter
    Aug 12, 2013
    16,146
    Glenelg

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    OLM-Medic

    Banned
    BANNED!!!
    May 5, 2010
    6,588
    Yeah I don't see a point. With any zero you still with have to aim high at close ranges due to the sight over bore height anyway.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    33,173
    ( Assuming we're speaking something AR- ish with significant spacing between bore center and sights ) you would be hitting significantly high beyond 15yds in exchange for a fraction of an inch closer at less than 15yds . If you would ever use it at more than 15yds for any reason , that doesn't strike *Me* as a worthwhile trade off .

    If you absolutely , positively never, ever will shoot beyond 15yds , a plain bead front sight is ideal . ( See what I did there ?)
     

    smokey

    2A TEACHER
    Jan 31, 2008
    31,509
    Go with a 50 yd zero, learn how to factor in height over bore at different distances, and realize you'll likely be ok point-shooting inside a house anyway.

    Also, don't use subsonics for defense. They suck compared to supers. Here's a chart I made up for my 8.5" blackout running the vmax load in it right now. It's zeroed at 50, which makes it pretty darned flat out to about 250 yds.
     

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    babalou

    Ultimate Member
    MDS Supporter
    Aug 12, 2013
    16,146
    Glenelg
    ok not to be like the 9 versus 45 but some do 36 yard or 37 yard versus 50 yard. I know not relevant to this thread. I was just curious. My 300 pistol has a 9" barrel- Springfield Saint Victor
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,999
    At 15 yards, you're basically point shooting. Sight for 100 yd zero and learn where you hit at 15.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,719
    Not Far Enough from the City
    Given your target size, and especially gven defensive shooting realities, you'll never need nor effectively utilize any tiny "advantage" in practical terms of a 15 yard sight in. You will however, impact longer range capability. Even though you think you won't need it, why compromise it?

    You lose more than you gain in doing so. Now if you were shooting a 15 yard precision basement parlor game, that's an entirely different animal.
     

    OLM-Medic

    Banned
    BANNED!!!
    May 5, 2010
    6,588
    ok not to be like the 9 versus 45 but some do 36 yard or 37 yard versus 50 yard. I know not relevant to this thread. I was just curious. My 300 pistol has a 9" barrel- Springfield Saint Victor

    I recall 36y being good for 300blk. Can't remember though.

    I would use subsonic for HD either unless you are using something premium like Lehigh ammo. In fact, I would want premium ammo for supers too, like Barnes. That's the biggest reason I sold my .300BO. Ammo is expensive. At least cheap .223 can fragment.
     

    platekiller

    Ultimate Member
    Jun 7, 2011
    1,780
    Martinsburg, WV
    personally, I do not see much difference in since so close. Here are a couple links for longer. I assume just shrink some.. The beginning of the trajectories are real close at the beginning.

    https://news.aroutfitting.com/2018/09/24/what-range-to-zero-your-ar15-50-yards-100-200/
    https://youtu.be/NVROVC6g6Cs

    Is the chart for 223/556 or 300 bo? I don’t have a blackout but I like that 36 zero line. 10” spread from 0-300 makes it so you can shoot center of mass and make a hit within a minute of bad guy.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,999
    ok not to be like the 9 versus 45 but some do 36 yard or 37 yard versus 50 yard. I know not relevant to this thread. I was just curious. My 300 pistol has a 9" barrel- Springfield Saint Victor
    You've gotten the pistol?
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    OK, with a 220 grain Sierra MatchKing at 1050 fps, if you sight in for 15 yards, at 40 yards the round will hit 2.6 inches above your point of aim. At 10 yards, it will be 0.8 inches low. At 20 yards, 0.7 inches high. 3.0 inches high at 50 and 3.2 inches high at 60.

    If you zero at 25 yards, you will be 1.3 inches low at 10 yards, 0.3 inches low at 20 yards, and 0.5 inches high at 40 and 50 yards. And 0.1 inches high at 60 yards.

    So, for zeroing for 15 yards, your shot will be half an inch closer at 10 yards, but already 0.4 greater distance away from point of aim at 20 yards, versus a 25 yard zero.

    For fun, the Maximum Point Blank Range for that round is 144 yards, with a 122 yard zero. At 10 yards, you will shoot 0.5 inches low, which is closer than the 15 yard zero. At 20 yards, you will be 1.2 inches high. At 40 yards, 3.7 inches high, and 50 yards, 4.4 inches high.

    But with that 122 yard zero, you would still hit the torso with a center of mass aiming point.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,728
    OK, with a 220 grain Sierra MatchKing at 1050 fps, if you sight in for 15 yards, at 40 yards the round will hit 2.6 inches above your point of aim. At 10 yards, it will be 0.8 inches low. At 20 yards, 0.7 inches high. 3.0 inches high at 50 and 3.2 inches high at 60.

    If you zero at 25 yards, you will be 1.3 inches low at 10 yards, 0.3 inches low at 20 yards, and 0.5 inches high at 40 and 50 yards. And 0.1 inches high at 60 yards.

    So, for zeroing for 15 yards, your shot will be half an inch closer at 10 yards, but already 0.4 greater distance away from point of aim at 20 yards, versus a 25 yard zero.

    For fun, the Maximum Point Blank Range for that round is 144 yards, with a 122 yard zero. At 10 yards, you will shoot 0.5 inches low, which is closer than the 15 yard zero. At 20 yards, you will be 1.2 inches high. At 40 yards, 3.7 inches high, and 50 yards, 4.4 inches high.

    But with that 122 yard zero, you would still hit the torso with a center of mass aiming point.

    What sight height did you use to calculate that? 1.5” is the standard for calculators. IIRC average height on an AR is more like 2.5”...
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    The issue is, when you use a close zero with an AR, you are really exaggerating the angular difference between the barrel and the line of sight.

    So past the zero distance, the bullet is still going up a good bit.
     

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    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,327
    OK, with a 220 grain Sierra MatchKing at 1050 fps, if you sight in for 15 yards, at 40 yards the round will hit 2.6 inches above your point of aim. At 10 yards, it will be 0.8 inches low. At 20 yards, 0.7 inches high. 3.0 inches high at 50 and 3.2 inches high at 60.

    If you zero at 25 yards, you will be 1.3 inches low at 10 yards, 0.3 inches low at 20 yards, and 0.5 inches high at 40 and 50 yards. And 0.1 inches high at 60 yards.

    So, for zeroing for 15 yards, your shot will be half an inch closer at 10 yards, but already 0.4 greater distance away from point of aim at 20 yards, versus a 25 yard zero.

    For fun, the Maximum Point Blank Range for that round is 144 yards, with a 122 yard zero. At 10 yards, you will shoot 0.5 inches low, which is closer than the 15 yard zero. At 20 yards, you will be 1.2 inches high. At 40 yards, 3.7 inches high, and 50 yards, 4.4 inches high.

    But with that 122 yard zero, you would still hit the torso with a center of mass aiming point.

    And all with a matchking. Aka ice pick
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,327
    I would bet that most any similar weight bullet would give very close those numbers at those ranges. They are pretty close ranges.

    Point being terrible home defense or hunting bullet. Not meaning trajectory. Should have clarified.
     

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