Question about bullet drop

[Prc329]

I searched but did not find the answer I was looking for.

Assuming the world in perfect, I do my part, no wind period, and my zero is perfect at 100 yards. Shooting 168 grain black hills 308 from my Savage 10fp. How many inches low would I be at 300, and 600 yards?

[30Cal]

The standard come-ups which work for most nominal stuff you'll feed a 308 or 30-06 are:

From 100 to 200yds, come up 2 minutes
from 200 to 300yds, come up 3 more minutes (2 1/2 usually)
And from 300 to 600yds, it'll be 12-14 minutes more.

[ocabj]

Why not just run the ballistics information in JBM?

The 2-3-11 rule is good for getting on paper for 200-300-600 on a High Power Rifle target.

[kap]

Break out you wind speed meter, thermometer, barometer and humidity meters. Ballisticard probably more information than any person at the range really needs to know on one little laminated card.

http://www.ballisticards.com/

[ocabj]

Again, just use JBM. Plug in your recorded MV of the ammo out of your specific rifle along with the correct bullet. That's it. Why pay for a "Ballisticard" when all they're doing is using a ballistic calculator like the free JBM calculator? You're just paying for the fancy lamination.

[kap]

I have tried the JBM calculator and while their numbers are the same as ballisticards, their lack of color coding corresponding the average ambient temperature really affected my ability to hit the target.

[Pthfndr]

I have tried the JBM calculator and while their numbers are the same as ballisticards, their lack of color coding corresponding the average ambient temperature really affected my ability to hit the target.

NO ballistics program will more than get you on paper, no matter how much info it provides. You will need to CONFIRM everything by actually shooting the rifle with the chosen load.

I shoot 1000 yard competition, and I seriously doubt anyone else who does will disagree with me. I've had ballistics programs be off as much as 4 MOA at 900 and 1000 yards.

[Prc329]

Thanks for the info guys. I was looking for the very basic information. I need to play with jbm. All the info I seem to find on my chosen factory load is velocity,

[nic]

Stupid question here, but what is JBM?

[rksimple]

I have tried the JBM calculator and while their numbers are the same as ballisticards, their lack of color coding corresponding the average ambient temperature really affected my ability to hit the target.

http://www.eskimo.com/~jbm/calculations/traj/traj.html

What? You can do the same thing in JBM. That company does the same thing you can do on JBM. If ambient temperature is your problem, the ballisticards can only adjust for pressure density really. How are they going to know how temperature sensitive your load is? In my last match, I was more than 2 MOA high just from a 25-30 degree temp swing (I know; time to switch powders). There are far more variables than meet the eye.

Pthfndr said it right. Those programs will get you on paper, but you need to confirm everything by shooting your rifle at various known distances and conditions.

[Prc329]

http://www.eskimo.com/~jbm/calculations/calculations.html

[ocabj]

NO ballistics program will more than get you on paper, no matter how much info it provides. You will need to CONFIRM everything by actually shooting the rifle with the chosen load.

I shoot 1000 yard competition, and I seriously doubt anyone else who does will disagree with me. I've had ballistics programs be off as much as 4 MOA at 900 and 1000 yards.

True. But I've found that JBM's calculations are very close, at least for mid range.

At the US Navy Pacific Fleet EIC Match last Thursday, the slow fire prone stage was fired at 500 yards (as opposed to 600). I had never fired my 600 yard load at 500 yards before. According to the JBM table I had printed out using my load information (MV and bullet), it said I needed 4.1 to 4.3 MOA down from my 600 yard zero. Since EIC matches have no sighters, I was going on faith. My 600 yard zero is +60 from bottom. So 4MOA with 1/4 MOA clicks is 16. I dialed in +44 from bottom. Took a shot. Wide 8 to the left (due to wind), but dead on for elevation. Ended up dialing down 1/2 MOA due to the lighting condtions during the 1st 10 round string, but the dope was good.

Of course, all this is in my data book so I have a live fire reference to go back to.

[Mute]

If you can fill in the correct parameters, especially the velocity of your chosen ammo for your rifle, JBM is very accurate.

[rksimple]

When I did a 1000 yard shoot at Sac Valley, JBM was off by 2 MOA at that distance for my load. Granted, I didn't have the barometer reading for that morning, but 21 inches is a lot if you want to win.

[Prc329]

Time to buy a chronograph along with my dillon I am ordering.