7mm rem mag

Discussion in 'Modern Firearms' started by swampking, Oct 18, 2017.

  1. swampking

    swampking 6 pointer

    110
    3
    Oct 17, 2010
    shooting 139 grain hornady whitetail.
    100 yards- zero
    200 yards - 3 inches high
    300 yards- 3 inches low

    Question is why is it high at 200. Scope is mounted as low as it can be
     
    WILD likes this.
  2. model70

    model70 8 pointer

    662
    228
    Jan 11, 2011
    Western Ky
    I need to shoot mine some more tommorow, but those numbers dont add up with the way mine was shooting. Im also shooting the 139 hornady whitail loads. Mine was about an inch high at 100 and about an inch and a half at 200. Havent shot 300, not enough field behind my house. What do your groups look like( how big)?
     
  3. JDMiller

    JDMiller 12 pointer

    10,750
    3,753
    Jun 12, 2005
    " Between the Rivers "
    Might be wrong here and apologize... but I read the OP’s post here as why is it high at 200 yds when it’s -0- at 100yds.

    Which with any caliber or load it’s not uncommon ..as you may be -0- at 100 yds but the bullet is still on the rise... so to speak. Being there’s a lot of technical ways to explain it ... but the jest is the bullet rising above a direct line of sight to the target. Which you have to think about a bullets trajectory.... being an arc of sorts.

    The bullet once it leaves the barrel is continually on the rise above a direct line of sight to a certain distance then as it looses velocity it begins to drop. In your case .. somewhere between 200 & 300 yds it crosses that line of sight or -0- and it’s on target dead center again.

    Which the way your sighted with a -0- at 100 yds is fine for the majority of Ky deer hunting. You could easily hold the crosshairs on the shoulder from any distance to 300yds and you have a dead deer with that caliber.

    Which there’s really no right or wrong way concerning sighting in a rifle at a certain distance as the most important thing is knowing what it’s doing at distances beyond -0- and understanding the limitation.

    But every caliber is different concerning distance potential. Many people sight in 3”inches high at 100yds where you can squeeze a little more performance at even longer distance like 400yds or further. But again it all depends on the caliber and it’s capability.

    In turn ... hopefully I haven’t muddied the waters in trying to explain it.
     
    JR PORTER likes this.
  4. swampking

    swampking 6 pointer

    110
    3
    Oct 17, 2010
    That makes sense. The groups are 3 touching at 100 about 1” apart at 200 and 3” at 300. Those are all from a solid rest
     
    WILD likes this.
  5. inchr48

    inchr48 10 pointer

    1,261
    96
    May 14, 2013
    NW Indiana
    Do a search on "Point Blank Range". Lots of good data out there, and some ballistic calculators to help you decide how you want to set your "zero". Sounds like it is all set to go hunting as is though, great groups.
     
  6. WILD

    WILD 12 pointer

    2,263
    154
    Sep 7, 2009
    hick town,ky
    Man,sounds like you have a tack driver.the .284 bullet is the most gravity deffien bullet ever made from all the stuff I have read...what kind oh gun and scope you using,sounds like a great set up and a great shooting rifle,must have some good glass also...nice.
     
  7. 120+

    120+ 12 pointer

    If it's shooting that way consistently I wouldn't touch it. I'd be good with that all day.
     
  8. KY Swamp Beagler

    KY Swamp Beagler 12 pointer

    3,561
    1,566
    Feb 20, 2011
    the swamps of western KY
    The old Petersen’s Hunting Magazine used to have a cartridge corner section that showed the bullet arc of all popular cartridges. The diagram and descriptions were really heldpful in explaining bullet flight.

    If you can get a copy of one or something similar they are very helpful.
     
  9. GentlemanHunter

    GentlemanHunter Spike

    69
    40
    Aug 10, 2017
    Fayette County
    As others were getting at, the barrel is below your scope, so your scope actually looks slightly down in comparison to the barrel. Thus, the bullet will cross "zero," as measured by the scope, twice: once near (as the bullet travels "up" to the plane of the scope) and another far (as the bullet falls back down to the plane of the scope). Based on your load, it's not logical that your "near zero" would be all the way out at 100 yards and the bullet still 3" above at 200 yards.

    I'd suggest with that load, you might want it sighted for a 224-yard "far zero," or 1.78" high at 100 yards. That way, you should be within 2 inches at any distance out to 261 without having to make adjustments. Your trajectory would then look like this:

    http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=ab2eee6b
     
  10. KY Swamp Beagler

    KY Swamp Beagler 12 pointer

    3,561
    1,566
    Feb 20, 2011
    the swamps of western KY
    I think in general 2” high at 100 yards would cover you for most high powered rifles.
     
  11. swampking

    swampking 6 pointer

    110
    3
    Oct 17, 2010
    Savage 111 with nikon scope
     
    JR PORTER likes this.
  12. 120+

    120+ 12 pointer

    That's what I've always heard but it doesn't work if he's at zero on 100 and 3 high at 200. That would put him closer to 5 inches high at 200 if the calculations are correct.
     
  13. JDMiller

    JDMiller 12 pointer

    10,750
    3,753
    Jun 12, 2005
    " Between the Rivers "
    I agree to the extent that's what the ballistic calculators shows based on the data plugged into it.

    But.... when it gets down to a particular gun & ammo with an "in the field" setting... ballistic calculators only get you into the relative ballpark. As there's variables that may be inconsistent in comparison to the calculator... sight height, barrel length and weather conditions (temp& humidity) could increase or decrease point of impact. Then there's the case of human error in general...as in most cases various types of sight in rest are used and the gun may not be locked down solid... or possibly a persons cheek weld or eye positioning deviates a little.

    Which a big one for me.... is simply my eyes aren't as good anymore as they use to be. Being a typical deer hunting set-up with a 3x9 with a duplex recticle...I'm ok at 100. But start trying to be precise at 200yds or much less 300 yds..... the crosshairs themselves become the enemy and I might not be holding a true dead center on the target. Where as...I could be the cause the rifle to shoot consistently higher because I'm not holding exactly where I need to be on the target.

    To me.... and don't get me wrong I love ballistic calculators... but the only way to know 100%...is to sight in and adjust accordingly based on bullet impact. If the results are different(higher or lower) than what the ballistic calculator states... I don't worry about it.
     
  14. GentlemanHunter

    GentlemanHunter Spike

    69
    40
    Aug 10, 2017
    Fayette County
    The OP's question was how it was was so high at 200. I too, am stumped as to how it could be dead on at 100 and then somehow rise 3" over the next 100 yards unless it started out something like 4.5" inches below the scope, but something you said grabbed me:

    I'm guessing that swampking is experiencing bad check weld/eye position in combination with parallax. Most scopes with nonadjustable parallax are set for no parallax at 100 yards. If he has a bad eye position due to cheek weld issues, he could still get an accurate zero at 100 yards without an issue. The problems would manifest when he stretched out to 200 and 300 yards. An offcenter eye position could then lead to untrue aim.

    Swampking, try this next time you go out: at your longer distances, take your normal mount, but then try to move your head without moving the rifle and see if the crosshairs move on your target. If so, you probably need to add a cheek pad to keep your eye position dead center on the scope.
     
  15. swampking

    swampking 6 pointer

    110
    3
    Oct 17, 2010
    Ok thanks
     

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