Thread: calculator able to predict projectile pass height over variuis distances

Originally Posted by LJPRMC

I have a dilemma.

The maximum range that i can sight my rifle into, is on a range that has shooting positions that end at a maximum distance of 368 mts . The "100 yd" position is actually at 91 metres .
So my rifle is sighted in at 91 mts .
I need to shoot to 600 mts
what height above the bull ( on the 91 metre target ) should my projectile strike in its trajectory to a 600 mt distance target ?
I can dial up the 600 mt range on my scope and for the projectile ( 175 gr eldx 7mm ) at 2950 ft/sec , the up is 51 clicks .
the projectile then passes thru the 91 mt target . 33.5 cm above the bull .

these things are true
the target distance ( and zero distance ) is 91 mts .
the projectile is 175 gr eldx , G7 0.3470 , L=39.8 mm ( in 7mm prc case )
the velocity is measured at 2950 ft/sec
the rifle is 7mm prc at 1:8 twist
the weather is 20 cel , and no wind
the altitude is 60 ft above sea level
the humidity is 60%
the scope is swarovoski z5 3.5-18 ( click value 0.7 cm or 1/4 inch )
Strelock says 51 clicks up from 91 mt zero
swarovski says 51 clicks as well
the projectile strikes high at 33.5 cm above the bull on the 91 mt target when dialed up 51 clicks

what calculator is available to enter the data i have , to confirm the apparent trajectory and strike on the 91 mt target, is likely correct for a strike on the 600 mt target ?

cheers
les

Thank you all for your input. your help has led me to the calculator i was after .
Here's an update: The rifle is a "light sporter" in 7mm PRC with a fluted barrel. Three rounds are enough to heat it up and cause shots to deviate. Therefore, cooling is essential (I use a battery-powered air mattress pump and garden hose). The rifle isn't PRS grade, but it consistently groups three rounds within 3/4 MOA (the fourth could land anywhere).

Realistically, I'm aiming for a single bullet to hit within a 30 cm diameter circle at 600 meters. In today's test, I managed to place two rounds within a 100 mm circle at 368 meters (400 yards). I saved the third round for a single shot at a tall target, then adjusted by 51 clicks to hit a 600-meter target. The last round struck 60.5 cm above the 368-meter aim point.

The round traveled downrange at 2955 ft/sec. The calculator predicted it should have hit 71.5 cm above the aim point to reach the 600-meter target. However, it hit at 60.5 cm. So, with only one round to consider, I'm 11 cm low, but I'm not reading too much into that. It's likely a result of various factors. After all, how likely would it be to hit exactly at the 71.5 cm mark?

Originally Posted by LJPRMC

Thank you all for your input. your help has led me to the calculator i was after .
Here's an update: The rifle is a "light sporter" in 7mm PRC with a fluted barrel. Three rounds are enough to heat it up and cause shots to deviate. Therefore, cooling is essential (I use a battery-powered air mattress pump and garden hose). The rifle isn't PRS grade, but it consistently groups three rounds within 3/4 MOA (the fourth could land anywhere).

Realistically, I'm aiming for a single bullet to hit within a 30 cm diameter circle at 600 meters. In today's test, I managed to place two rounds within a 100 mm circle at 368 meters (400 yards). I saved the third round for a single shot at a tall target, then adjusted by 51 clicks to hit a 600-meter target. The last round struck 60.5 cm above the 368-meter aim point.

The round traveled downrange at 2955 ft/sec. The calculator predicted it should have hit 71.5 cm above the aim point to reach the 600-meter target. However, it hit at 60.5 cm. So, with only one round to consider, I'm 11 cm low, but I'm not reading too much into that. It's likely a result of various factors. After all, how likely would it be to hit exactly at the 71.5 cm mark?

I'm not sure that you're clear about what you're trying to achieve.

You seem to be wanting to confirm that the output of a ballistic calculator will allow you to hit a deer at 600m.

The approach you are taking doesn't really give you the ability to know this.

Confirmation that the ballistic calculator solution matches reality requires shooting enough shots on targets at long enough range for errors to be detectable and have confidence that the error is real and not random variation. The magnitude of any errors in the ballistic calc at 368m will be very small.

The current approach mainly gives you a poor test of the straightness and value of your scope clicks.

Originally Posted by gimp

The current approach mainly gives you a poor test of the straightness and value of your scope clicks.

I get what your driving at completely.........
so the mathimatition inside me says...if your 51 clicks wasnt enough by say???1/6th if you add 1/6th amount of clicks you should in effect be correct now elevation wise.... IF that works you SHOULD in futre know that for EG instead of ten clicks you need to stick in 12....and try it
by doing so you remove any error in the dialing