Hello Fellas,

Question for you regarding trajectory.....I figured that this forum would be the best place to post since I know how you reloaders pour over those charts!!

I am currently shooting a 7mm Rem Mag with Federal (factory) Premium 160 grain Accubonds.

I would like to try the new 160 grain Trophy Bonded Tipped Federal loads. I compared the bullets side by side and can see that the trophy bullet is a bit longer than the Accubond even though they both weigh 160 grains.

Anyway my question is as follows:

Will these two loads have the same trajectory? I am using a calibrated turret knob (calibrated for the Accubond) and am hoping that I can use the same knob for both loads.

If they won't have the same traj, how much will they differ?

Thanks!!

Frank

Smarter guys than myself will probably chip in here, but here is what I think. Shoot them and find out. My 300 win loves Accubonds of any weight I send thru it, but they are expensive. I practice with SMK's. Same powder load/ same bullet weight. the Accubond always hits a bit higher. probably won't mean much until you get out there aways. Good Luck

Chain, correct.

Wolfgar

The only way to know for sure is to shoot them side by side in YOUR rifle.

Thanks fellas, and I agree that the only way to do it right is to shoot them both, but unfortunatly for me, I live in New York City and only have access to a 100 yard indoor range.

The only way I shoot further than that is when I leave the state for a hunt.

I was hoping that some of you would have some experiences with this situation, and that I could pick your brains for what I can expect.

Thanks!

All of the math and calculators and ballistics charts will give you the same answer to your question.

Shoot them at one hundred yards and then shoot them at 300 yards.

Now if they won't both group out of your gun, it really is a moot point.

Just an opinion of course.

Hey Wolfgar, You could go to each of the Bullet Manufacturer's web sites and get the Ballistic Coefficient for each bullet. If you have trouble finding it, call their Customer Service Toll FREE number and they will give it to you.

Then plug the data into one of the FREE External Ballistics programs found on the net and it will tell you what you want to know.

However..., there is always something to make the Computer generated Data "questionable at best" and totally misleading at worst:
1. You are having to "guess" at the actual Velocity.
2. Even though you will have a B.C. number, it is still only an estimate(aka a "guess").
3. The chance of the Trajectory being close enough from one Load to the next is typically going to require "both" Windage and Elevation changes from your barrel to have the same Point-of-Impact. This is due to the different Barrel Harmonics created by the diferent Cases, Primers, Powders and Bullets used in each Load.

But, there is good news:
4. At only 200yds, you could get each Load to hit the same Point-of-Impact with some Turret Cranking. Probably a bit of both Turrets will be required, but getting the POI the same is relatively easy if you do not mind making a Scope Adjustment between the two Loads.
5. Once you get the two Loads figured out, the mid-range Trajectory difference between those two Loads will not be enough for the average 7mmRemMag user(including me) to be concerned about.

You simply "Zero" the Turrets for the Load you intend to use the most and write the "Turret Correction" on the box of the other cartridges. For example, if you need 4clicks R and 2clicks D with the Second Load, then when you get ready to make the change you do the following:
6. Crank in 6clicks R and then 2clicks L.
7. Crank in 4clicks D and then 2clicks U.

The backing-up is to eliminate "Lash" in the adjustments.

But like the other folks said, you must actually shoot the Loads to see what they will do. No computer software can tell you what the Loads will really do. If you see someone post that they use a Computer Generated "Drop Chart" to Hunt with, that person knows less about firearms than clinton about honesty.

Best of luck to you.

I have always maintained that Hot Core is a knowledgeable and wise man!

The free-software I use is JBM - Calculations. They give a selection of bullets with their associated BC's but you can use your own figures too. It gives some idea of what to expect and is fun to play around with!

I'm not sure what question you are trying to answer. The trajectories of the two bullets will be virtually indistinguishable, assuming that their velocities are also similar.

However, they may strike the target at markedly different places using the same sighting point. In other words, each may require a significantly different "zero" than the other. However, if you properly sight your rifle to strike at, say, 2" above point of aim at 100 yards with either load, then the striking point at extended yardage for each load will be so close to the same that the difference will be deminimus.

Thank you all for the imput.

Stonecreek, I think that your awnser is what I'm looking for. I know that the 2 loads will impact differently and will require a sight-in, but once sighted in....my origional question is "what will the difference in trajectory/drop be between the 160 gr Accubond and 160 gr Trophy Tipped Bullet...given the same muzzle velocity".

So they "should be" almost identical at say 800 yards???

Am I correct here??

200-300 real close 800 ?? Hornady has an excellent free ballistics calculator, use it and it will be quite close.

quote:

Originally posted by Wolfgar:
...So they "should be" almost identical at say 800 yards??? ...Am I correct here??

No

quote:

Originally posted by Hot Core:

quote:

Originally posted by Wolfgar:
...So they "should be" almost identical at say 800 yards??? ...Am I correct here??

No

If you dial each in for 800 yd zero will have slightly different trajectories if for no other reason than they have different Ballistic Coefficients. The Federal Trophy Bonded Tip 7mm 160 gr. BC is .440 and the Nosler Accubond 7mm 160 gr. BC is .475

Assuming a muzzle velocity of 2900 fps, total drop with an 800 yd. zero would be 208.5" and 200.75" respectively - a difference of just under 8" at 800 yds.

To give you an idea of those trajectories, Max point blank range for a 12" target with the Trophy BT is 377 yds with the rifle zeroed at 320 yds.

Max 12" PBR for the Accubond is 380 yds and the rifle would be zeroed at 323 yds.

if one is longer then the other then
A. no aand
B. no
firstly they are going to be loaded to different lengths one way or the other.

Ratltrap,

I put them side by side and the Trophy Tip is longer than the Accubond....why then does the Tipped have a higher BC?

quote:

Originally posted by Wolfgar:
Ratltrap,

I put them side by side and the Trophy Tip is longer than the Accubond....why then does the Tipped have a higher BC?

Because that's what the manufacturer believes will help sell their bullet. Anyway, the length of the bullet is irrelavent -- it is the shape and density that determines BC.

Published Ballistic Coefficients are notoriously inaccurate. Besides, even if those published figures were accurate, a difference of .440 and .475 is tiny, even over several hundred yards.

You are going hunting, right? Forget 800 yards. 400 yards is a very long shot under hunting conditions. Run the "theoretical" ballistics tables on these two bullets and you'll find that at 400 yards there is not a crosshair width difference in them. In fact, the unknown difference in their velocities as loaded by the two different manufactorers will make more difference in their trajectories.

But a far greater consideration than the theoretical trajectory of the two bullet is the accuracy each displays in your rifle. If one is more accurate by a quarter of a MOA, then the difference in accuracy in the two makes a far greater diffence in downrange impact point than EITHER their BC or velocity.

My thought is that although there will be a difference in traqectory at a given distance, is it enough to be concerned with in terms of other variables in field conditions. My point, if you are shooting while leaning against a tree at 400 yards, the 3 or 4 inches variation between bullets pales agaist the shooters ability to place a small enough group under those conditions to make it matter. If you shoot well enough it is a concern, I don'y shoot that well, so I'm getting closer or getting a better rest.

the two bullets will have an identical trajectory between 300 and 800 yards. Specifically meaning, if you haven't shot them at that distance, you don't know where there are going to hit. You would just be guessing. so my answer is if you zero either one 2" high at 100 yards you'll bascally be at "no hold over out to 280ish yards and after that you won't know if you cant try it ahead of time. I do wish you the best of luck!