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I just purchased the Nosler reloading guide #6. I started looking up ballistic coefficients for my 7mm mag, with a 150gr nosler ballistic tip traveling approximately 3100fps. It is saying that sighted in at 200yds it will be 2.6in high at 100yds, 3.9in low at 300yds, 8.3in low at 400yds, and 13.4in low at 500yds. If my gun produces the same velocity is this truly what the bullet is going to do, not only for my 7mm but as well as the coefficients for my 243 and my dads 270?
 

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I could be wrong on this (I haven't run the numbers or anything, just guessing based on similar cartridges and such), but I would think it should be more like 1 1/2" high at 100, 0" at 200, 6" low at 300, 18"" low at 400 and about 36" low at 500?

Your actual trajectory will be affected by the atmosphere, however. Wind, temperature, and most importantly, elevation all play a part in it.

The other guns will likely be similar depending on bullet selection, however loaded with an appropriate deer round, you would likely be looking at around 6" lower than the 7mm Rem Mag at the 500 yard mark.
 

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My Nosler Fifth Edition lists the B.C. of the Ballistic Tip in 150 grains as .493. If started at 3100 fps, the same manual predicts the trajectory of a round zeroed at 200 yds as being 1.3" high at 100; on at 200; -6.5 at 300; -17.4 at 400; -35.2 at 500.

Now those numbers are calculated "approximations" from a table, but I would expect them to be very close to actual fact. I don't have the Nosler #6 manual, so I cannot comment on the OP's numbers except to say that they seem odd to me.

If you shoot bullets with the same B.C at the same initial velocity, you should get very similar trajectories regardless of caliber. That is the basic assumption of ballistic tables such as those in many reloading manuals that give trajectories calculated on B.C. and initial velocity figures.
 

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I don't personally have any Snozler manuals, but MOST folks correct ballistics to a "standard". This is usually something like 60 degrees, and sea level. Unless you are shooting in that set of conditions, it won't be exactly the same.

The other thing to consider is that folks like Nosler and Hornady, round off the BC, of their bullets. Bullets have different BC values at different speeds. Sierra lists these varying values seperatly.
 

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I just purchased the Nosler reloading guide #6. I started looking up ballistic coefficients for my 7mm mag, with a 150gr nosler ballistic tip traveling approximately 3100fps. It is saying that sighted in at 200yds it will be 2.6in high at 100yds, 3.9in low at 300yds, 8.3in low at 400yds, and 13.4in low at 500yds. If my gun produces the same velocity is this truly what the bullet is going to do, not only for my 7mm but as well as the coefficients for my 243 and my dads 270?
joe,

Something is way wrong with those trajectory numbers - Find you another source!
 

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I just happen to have a couple of my ballistics tables handy for my 7mm and my .243.

My 7mm Mag shooting 160 gr Nosler Accubonds @2810 fps with BC of ~0.531 shoots:
100: +1.6 in, 200: 0 in, 300: -7.3 in, 400: -21.1 in, 500: -42.3 in

My .243 Win shooting 95 gr Nosler BT's @2945 fps with BC of ~0.379 shoots:
100: +1.5 in, 200: 0 in, 300: -7.2 in, 400: -21.4 in, 500: -43.8 in

For the 7MM a quick ballistics calculation using your numbers with simialr conditions listsed above shows:
100: 1.2 in, 200: 0 in, 300: -5.9 in, 400: -17.2 in, 500: -34.8 in

And the .243 at the same speed with a 95 gr BT:
100: +1.3 in, 200: 0 in, 300: -6.4 in, 400: -19.0 in, 500: -38.9 in

One thing to keep in mind is that both bullets being pushed at 3100 fps is getting quick and that is at the top end of Max loads for those rounds.

My ballistics are fairly close to each other, but the BC's, weights, and FPS are all different. These were loads that I worked up for each rifle and they shoot really good in each rifle. I just got lucky as to them being ballistics twins (not including the wind drift).

So I guess to answer your questions, I would say yes, if you can find two bullets with the same BC, and same FPS weight will not matter. that being said, those published numbers are just a reference. The only way to truly know what a bullet is going to do is to type in all your variables in a calculator, and shoot it to see where exactly it hits. Sometimes even the calculators are off.

Weight will not matter because gravity is a constant and a 10 lb weight will fall just as fast a a 1 lb weight.
 

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Joe,

I have the #6. You simply used the table incorrectly. Look on page 776. The bottom table on the page is the one that starts at 3100 fps (darker orange than the one above it). Now look at the fourth column of numbers from the left. If you look all the way up that column to the black bar 3/5 of the way up from the bottom of the page, you will see this fourth column of numbers is labled "Zero (200 yds)" at the top. This is the only column you want to look at for your drop numbers.

What you did was look left and right, picking up numbers from the 100 yard zero column on one side, and the 300 yard zero and 400 yard, and 500 yard zero column numbers on the other side.

Instead, look for your muzzle velocity in the second column from the left. To its left, in the first column, you see "0". That's the range column. Now look down two rows where that first column says "200", and look over to the fourth column (the 200 yard zero column) and you will see 0.0". That because this is a 200 yard zero column. Now look all the way back at the range column and go up one row to where it says "100". Now look across from there to the fourth column and you will see "1.3", one row up from where the 200 yard zero column said "0.0". That is the 100 yard point of impact (POI). Go back across from "1.3" to the range column and down two rows to where it says "300". Now go back across from there to the fourth (200 yard zero) column, and you will see -6", one row below where it said "0.0". That is the 300 yard POI. One row below that is 400 yards, where drop is -17.4". One row below that is 500 yards, where the drop is -35.2". And 600 yards is -60.2" yet one more row below that.
 
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