Quantcast
  1. Sign up now and join over 35,000 northwest gun owners. It's quick, easy, and 100% free!

POA vs POI for both pistols and rifles

Discussion in 'General Firearm Discussion' started by Chipperxd, Dec 7, 2011.

  1. Chipperxd

    Chipperxd Buffalo Active Member

    Messages:
    704
    Likes Received:
    182
    Hey all,

    I was watching a Julie Golob vid where she is sighting in her M&P pistol at various distances and had a question.

    When shooting at distances 25 yards or greater, you have to aim low with a pistol.

    When shooting at distances under 50 yards, you need to aim high with a rifle.

    Is this true or did I get it *** backwards?

    :huh:
     
  2. civilian75

    civilian75 Hillsboro, OR Well-Known Member

    Messages:
    1,392
    Likes Received:
    627
    Think you got it backwards. But your numbers are off. In a simplified model, the major contributing variables to a bullet trajectory are muzzle velocity, bullet resistance to air (drag), firearm zero. At close impact distances (less than 25yds), the distance between the muzzle and the sighting system (scope or iron sights) will start having a have significant effect on the POI v. POA.

    For a rifle, you could be aiming low well over 50yds. In a rifle zeroed at 300yds, the highest point in the parabola is somewhere between 150 and 200yds. Check this graph pasted from Wikipedia. It depicts the trajectory of bullets fired by a two rifles, one zeroed at 300yds and the other at 350yds.
    300px-M855_drop_during_25-meter_zeroing_trajectory_M16A2_M4.jpg
    http://en.wikipedia.org/wiki/External_ballistics
     
    Misterbill and (deleted member) like this.
  3. hermannr

    hermannr Okanogan Highlands Well-Known Member

    Messages:
    1,830
    Likes Received:
    871
    Think of it this way: Your line of sight is above the path of the bullet when the bullet leaves the barrel. The sights are generally adjusted so that the projectile will climb to meet the line of sight at some point depending on what distance the weapon is sighted in at. After the projectile goes soem distance farther it will come back down again and cross that line of sight.

    On my Rem 700, 264 win mag, if I am at "0" with the line of sight at 25 meters, I am at "0" again at 250 meters, therefore to be dead on at 100 meters I will have to aim about 1" low of my line of sight.

    On a pistol, I think most will cross the line of sight at about 7 meters, and some may be dead on again at 25 meters. I don't know for sure as all of my pistols are seriously different, and I rarely shot them over 25 meters. With a pistol I would print it on paper at different ranges before I made a statement. I have ons that fire .22 short, 22 LR, 22.Mag, 7.62X25mm, .38 special, 9X17, 9X18, 9X19..They are all so different. How can you compare a 7.62X25 at 1700 fps with a 9X17 at 850 fpc? you need paper, or a 22 short with a 22 mag? Each will print differently.
     
  4. Misterbill

    Misterbill Yakima County, Washington New Member

    Messages:
    1,308
    Likes Received:
    1,013
    With my current carry gun (XDM .40 3-inch barrel) I won't bother shooting at you past 25 yards and not even at 25 if you're moving or using cover.

    After 25 yards it's time to start thinking about running, not fighting.

    With my full-size guns I can drive tacks at 25 and reliably hit with time to aim at 50. But that 3-inch barrel limits my range a lot. It's ok, since something like 95% of all shooting happen at under 12 yards, the majority at under 20 feet.

    Rifles are their own beasts. But pistols are meant to be a close-quarters weapon, not something you're killing people 50 yards away with. At those distances it's past time to get the long guns.
     
  5. Chipperxd

    Chipperxd Buffalo Active Member

    Messages:
    704
    Likes Received:
    182
    I was referring to 25+ yrds for sd situations but more for competition. Have no plans to shoot anyone at those distances.

    Thanks for all the input everyone. Appreciate it.