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Old October 13, 2001, 07:19 AM   #1
MP-44
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7.62x39 Trajectory?

I want to sight in my Ak in so that the bullet does not rise more than 3" over the line of sight at its highest point. To get this trajectory what would the POI be at 25yds? Also if sighted in with the 3" max rise what would the trajectory be from the muzzle to 200 yds? Thanks
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Old October 13, 2001, 07:57 AM   #2
G3
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This for a 122 gr bullet at 2300 f/s.

Zero rifle at 21 yards (19m) and the bullet will strike inside a 3" circle out to 217 yds (200m).


I don't understand your second question.
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Old October 13, 2001, 08:23 AM   #3
MP-44
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My second question is, if the max trajectory is +3" then what would the POI be at 0, 25, 50, 100, 150 & 200 yds?
G3, that is a flatter trajectory than I was lead to believe that the 7.62x39 round was capable of. Did you get this info from experience or from other sources. Thanks!
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Old October 13, 2001, 09:30 AM   #4
Jamie Young
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I'll tell you this............
If you shoot it 300yds the bullet will drop about 3ft.
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Old October 13, 2001, 10:56 AM   #5
G3
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MP-44,

I was taught to use this zero John Farnam's Urban Rifle course.
I have shot my AK with this zero out to about 200 yds. I was shooting a 12" gong and consistently hit it. I can only say my groups good enough to get hits on the gong. At 100 yds, I can get a 3-4" 5 shot group on a paper target from unrested prone. The zero works fine.

Using the above zero will keep the bullet impact within a 3" or 8 cm circle from 21yds to 217 yds. The bullet will be 3" high at 106 yds, dead-on at 186 yds, and 3" low at 217 yds.
If you want a more detailed trajectory info, download one of the free ballistics programs.


From 25 yards and closer, most semi auto rifles have bore-to -sight-line offset. On my AK it is about 2.5 inches. This means I need to hold my sights about 2.5" high to get accurate hits. This holder over problem is most likely to become an issue when making head shots but, you must remember to hold over if shooting at an obscured portion of your enemy. Past 25 yds don't worry about hold overs just aim and shoot, that is what the battle sight zeroing is for.

By the way, at 300 yds, aim at the head for a chest shot. The drop of the bullet is 23". Shooting past 300 yds with an AK is not recommended. The drop at 400 yds is 61". Remember past 200 yds the wind will become a MAJOR problem aside from the bullet's trajectory.

Hope this helps.

Last edited by G3; October 13, 2001 at 11:21 AM.
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Old October 13, 2001, 11:30 AM   #6
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Thanks G3. Thats close enough to what I was looking for.
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Old October 13, 2001, 01:01 PM   #7
G3
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No problem. If you have any other questions feel free to ask.

Once you get the rifle zeroed at 21 yards you're good to go for about any combat shooting situation. Without an optical sight most targets are hard to see and hit at 200 yards. I believe 200 yds to be about the farthest anyone is going to realistically hit their target in combat.

Also, as a general rule if you sight a rifle in at 1" high at 25 yds your rifle will have a battle zero to 200 yds.
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Old October 13, 2001, 05:34 PM   #8
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If you follow G3's directions, here's a table:
Code:
 _BC_ _MV_         0      25      50      75     100     125     150     175     200     225     250 | YARDS
0.252 2300 >   -1.41    0.35    1.75    2.68    3.08    2.92    2.16    0.75   -1.26   -4.11   -7.61 | > 7.62x39 123gr SP
                Far zero at 185.9, maximum 3.09 at 106.1, angle 0.00228 rad 

0.295 2300 >   -1.41    0.30    1.65    2.54    2.92    2.76    2.04    0.70   -1.18   -3.83   -7.23 | > 7.62x39 130gr SP
                Far zero at 185.9, maximum 2.93 at 106.1, angle 0.00222 rad
I'm not sure which load is closer to what you're shooting.

If you sight in at 200y, you get this:
Code:
0.252 2300 >   -1.40    0.51    2.07    3.15    3.71    3.71    3.11    1.85   -0.01   -2.71   -6.23 | > 7.62x39 123gr SP
                Far zero at 200.1, maximum 3.78 at 113.7, angle 0.00245 rad 

0.295 2300 >   -1.41    0.44    1.95    2.98    3.51    3.50    2.92    1.73   -0.01   -2.52   -5.77 | > 7.62x39 130gr SP
                Far zero at 200.1, maximum 3.57 at 112.6, angle 0.00238 rad
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Old October 13, 2001, 07:42 PM   #9
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smithz, Thanks! Thats exactly what I wanted.
Thanks again for all replies.
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Old October 13, 2001, 07:54 PM   #10
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G3, a minor quibble: if it's 3" high at one point and 3" low at another, that would be a six inch circle, or am I off? Still close enough, though.
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Old October 13, 2001, 08:21 PM   #11
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http://www.handloads.com/calc/

this websight will answer all your ballistic calculation questions. it is great.
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