Sighted in Rifle... Where's it gonna hit?

[MackRack]

I sighted in my rifle today. Winchester Model 70 7mm Rem. Mag w/ Zeiss Conquest 3-9x40. I have found that the Remington Premier Partition in 150 grain is a load that my gun likes. I have it at about 1.5 to 1.75 inches high at 200 yards. I started out at 25 to zero than at 100 than to 200. So I know where its gonna hit at these distances. My question is where will it hit at 250, 300, 350.....? I have viewed a few ballistics charts but figured I'd talk to the actual shooters/experts. Any input is appreciated.

[frizzellr]

The only way to really know where it will shoot at those distances is to shoot it. Ballistics tables are a guesstimate at best. All rifles are individual.

[MackRack]

I realize that I need to shoot it at those distances. The place I used to sight it in only accomodates about a 225 yard shot. I was just wondering approximately where I need to aim at longer distances. Thanks.

[Virginia7]

MackRack,

Here's a link to a site that may help you out;

Link: http://www.biggameinfo.com/index.aspx

One thing I've noticed in checking ballistics tables, if you know the drop at 300yds., you can approx. the drop at 400 & 500yds. For example, if the drop is 6" at 300yds., then
it should be approx. 18" at 400, and 36" at 500yds. Notice, I said approximate. It can vary a couple inches. Check your reloading manuals or cartridge tables (Remington, Federal, etc.) if you don't believe me. I refer to it as the triple/double. Whatever the
drop is at 300, it will triple that amount at 400, and double that number at 500yds.
I guess it has something to do with the constant of gravity (?). As noted though, you have to know the drop at 300yds. Note: does not apply to likes of 30-30, 45-70, etc., and not sure ref. the newer ultra-mags, but seems to hold up for .308Win., .270, 30-06,
7mm Mag, etc. Oh yeah, forgot to mention, this seems to apply when figured for a
200yd zero.

As also noted however, it's best to sight in your particular rifle/load combination, and then check it out at the ranges you expect you may be using it, if at all possible. Every
rifle is sort of a law unto itself .

[skeeter 7MM]

I have my 150 NBT's sighted in pretty similar and actual shooting at 250 - 1/2", 300 - 3 1/2", 350 - 9" and 400 - 13".

Like mentioned though this is only a real rough guess for you at best, you should get out and shoot it to see what your actuals are at the distances mentioned. If you use rem ammo you can download their ballistic software free from the website which includes their ammo offerings, again though it is only for rough guess work...a starting point if you will.

[mistahmojoryan]

I'll echo the sentiments of the other posters. You really need to shoot a group at 300 to know how fast the bullet is dropping; no way around that. A lot of guns I've owned and seen others with will be great at 100 and 200 and then drop off the charts at 300. 6-12" lower than the ballistics chart tells you. As long as you hold a little high at 300 it's not a problem but trying to extrapolate where the bullet will be PAST 300...well, good luck.

I've punched #'s into ballistics programs til I was blue in the face and couldn't get the downrange trajectories to come close to what I'd already found out at the range.

lol, I think I've spent 99% of my time worrying about the 300+ yard shot and in the field I've never shot anything beyond 100 yards!

[sealgair243]

There was a nifty FreeWare Program that Remington Released called "Shoot" that was a ballistics program, but it allowed you to get GRAPHICAL comparisons of the drop, energy, deflection, and velocity. You would imput the range at which it was "zeroed" and would allow you to examine the graphs with the above variables with respect to time. This isn't a difficult technology, and I'm surprised there isn't a bigger program out there already to do this for more than just remington rounds. Its just a Quadratic equation, though it has to take in the zero range, ballistic coefficient, muzzle velocity, and such to compute it. Ok, so its more than just a quadratic, but that's the basic equation for how the trajectory is going to behave over time. Interestingly enough, because of the energy equation Ke= .5m(v^2) where v is the velocity of the bullet and m is the mass, you can see that a faster bullet will have a square relationship to its kinetic energy. This is interesting when it comes to optimization, because for some ranges, the lighter, faster bullet will have more energy (read: more knockdown power) and a more massive bullet will have less. But depending on how air friction acts on these bullets, there may be a point at which a larger, slower bullet has equal energy to the smaller bullet. This can be important for determining caliber for what ranges you typically shoot. Again, this is a complicated thing because it requires lots of steps to compare loads, but again, the computer programs can make this go much faster and more efficiently.

[MackRack]

Thanks for everyone's input. I have accessed a few ballistics charts to get an approximation of where I'll be out past 200. I realize I need to shoot the rifle at these distances to actually know what's going on and hopefully I will be able too. Thanks for your help though, now I have an idea of where to place my shots instead of just guessing.

[handloader1]

MackRack:

Your 150 gr. bullet should be traveling at about 3110 f/s, and your BC. is .456. At 250 yds. you will be around -.4"; at 300 yds. -3.5"; at 350 yds. -8.2. Good luck.