bullet drop????

[mr crab]

Went to the range last night. Sighted in a .243 with 80gr. custom made barnes tipped tsx's, and a .270 with 150gr. win. power points. I sighted in both rifles 3 inches high at 100yds. My question is.....where will the bullets hit at 200yds. None of the ballistic calculators I've found allow for a high zero point at 100 yds. I have played with them by changing the zero point and have come up with only more questions because changing the zero point changes the initial angle of the bullet. I do not have access to a 200 yd rifle range which would be the obvious answer here. Just hoping somebody here has experience with these type of ballistic questions. My ultimate goal is for the bullets to be dead on at 200 yds, and I think It will be pretty close, just wondering from more of an educational stance. TIA

[southern151]

PM Mathgeek. He'll likely know. I'd say you'll likely be spot on with the .243 but, still high with the .270. I'd say it depends on the speed of the round.

[southern151]

http://ballisticscalculator.winchester.com/

Have you tried this site yet?

[MathGeek]

Without any more information (muzzle velocity and ballistic coefficient), I would recommend sighting in 2" high at 100 yards to be close to zeroed at 200 yards. If you sight in 3" high at 100 yards, your zero will more likely be somewhere between 250 and 300 yards and you might be as much as 4-5" high at 200 yards. Longer range trajectories are much more sensitive to details such as muzzle velocity, ballistic coefficient, and air density.

[Top Dawg]

Not sure about 150 grain on the .270 but I shoot 130 grain and 2" high at 100 is pretty close to zero at 200 yards

[swglenn]

Try this site:

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

I have found it to be very close. I used it when I started long range shooting. I had a 100 yard range to sight in and needed to know where to set my scope for 600 yds and eventually 1000 yds. In both cases when I shot I was on the target and only had to make minor adjustments to be dead on.

Looking quickly at your rifles they both drop about 3.2" so you are closer to 3" than you can hold the rifle.

I assumed a 3000 fps velocity which should be close for both your rifles. If you have a chronograph you can put in your actual numbers. The bullet library is pretty extensive. When you select your bullet it will use the library data for the calculations. You don't need to fill in the BC, caliber, or bullet weight.

My bullet drop at 1000 yds is about 274 inches, almost 23 feet.

[fishfighter]

3inches is too high for that bullet at 100 yards, you need to be at 1.87 inches at 100 yards to be dead zero at 200 yards, 3inches at 100 yards you will be dead zero at 245 yards

[mr crab]

Originally Posted by fishfighter

3inches is too high for that bullet at 100 yards, you need to be at 1.87 inches at 100 yards to be dead zero at 200 yards, 3inches at 100 yards you will be dead zero at 245 yards

I saw that too, but that is how high the bullet will be at 100yds assuming an initial zeroing@200yds.....i don't think the math works backwards like that, which raise my initial question. Or am i thinking about this wrong?

[fishinpox]

How long of shot do you anticipate taking?
Also you can zero it in at 100 yards and buy a custom turret http://kentonindustries.com/

And just dial in you turret once u range it

[fishfighter]

i believe you are over thinking it!! but i may not be quite understanding your question, i may be under thinking it, i see on the chart that if you zero at 100 yards and that puts you 3inches low just under 190 yards, and 3.72 inches low at 200 yards, so with you three inches high at one hundred yards that should put you .72 inches low at 200 yards, i understand your confusion cause it seems off that you need to be 1.87 at 100 to be zero at 200, you have to keep in mind the arch of your bullet, you will have some rise and then the drop, you will be zero twice, near zero and far zero(hopefully your 200yds) you are still rising at 100yards

[fishfighter]

balistics

[mr crab]

Originally Posted by fishfighter

i believe you are over thinking it!! but i may not be quite understanding your question, i may be under thinking it, i see on the chart that if you zero at 100 yards and that puts you 3inches low just under 190 yards, and 3.72 inches low at 200 yards, so with you three inches high at one hundred yards that should put you .72 inches low at 200 yards, i understand your confusion cause it seems off that you need to be 1.87 at 100 to be zero at 200, you have to keep in mind the arch of your bullet, you will have some rise and then the drop, you will be zero twice, near zero and far zero(hopefully your 200yds) you are still rising at 100yards

I get it now....you are absolutely right.....I over compensated...I gues I'll just aim a little low unless I can get back to the range before the opener. Thanks, I knew I had something messed up, just not how or what, I'm on target now.

[newguy]

+3 is too much especially with the 80 gr. TSX. +1.75 will be pretty close, as close as you'll likely get without actually setting up @ 200 to verify.

[bearwash87]

1.26 inches high at 100 yards for the .243 and 2.06 inches high at 100 yards for the .270. They will both be on at 200 yards. This is using the Nikon spot on app