Home Forums Reloading Big Game Rifles Ballistics data

I've got a several year old RCBS ballistics program, but it shows my 30/06 as being zero at 25yds and zero at 200 and I know that's not right. Is there some place on the net I can go and get ballistics dats, such as bullet drop and bullet enrgy would be more accurate?

Actually that is Correct.
<br>The bullet leaves the muzzle apx 1.5" below your line of sight (assuming a scope) crosses that line of sight the first time at apx 25yds. The projectile stays above the line of sight until it gets to 200yds and then continues to drop farther below line of sight for the rest of its flight.
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<br>With a modern Centerfire such as 3006 you will have 2 zero ranges unless you are zeroed apx 75 yds or so. At that range the bullet will hit LOS once and then fall below it.
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<br>Barry

It dosn't seem to work that way though. Even at 200 they still seem to be climbing. I'll verify again tomorrow morning, but I know that I hit 5" to 6" at 100yds and 6" to off the paper at 200 when I zero at 25yds with my rifle shooting 2899 fps average.
<br> One of my 06s shooting 2556 fps average, I zeroed at 50yds and hit 1" low at 200yds.
<br> Tommorrow I'll take my son's 308 Savage to the range and after zeroing at 25,( perfect center, one after another in the same hole), we'll go to 200yds and it will shoot 6" to 8" high and to the right. It doesn't make any difference who the shooter is, either.
<br> This has been bothering me for some years, now. Anyone else see the same or any comments?

I would forget about sighting-in @ 25 yds and sight-in 1.5 to 2" high @ 100yds. Depending on bullet weight,that should get your 308 and 30-06 hitting close to dead on @ 200yds.
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<br>Your scope's parallax will give you fits trying to sight-in at close range(25yds).

We'll find out this morning yet. I'm heading out now, and that's just what I'm going to do. According to my ballistics dats, the 308 should hit about 4" low siting at 100yds.

Terry,
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<br>You mentioned 2899fps & 30-06. I punched those in my ballistic's program and assumed a 150gr bullet with a BC of .379 and got these numbers;
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<br> 25yds 100yds 200yds 250yds
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<br> -0.30" +1.69" 0.00 -2.97"
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<br>This seems to be a good practical zero for hunting.

That would be nice if the gun actually hit that way. The numbers at 25 and 200 are close, but at 100yds it's almost 6" high. I'm shooting the Nosler CT Silvertip 168gr with a CO of 490.
<br> This has been the norm with several different loads and bullets 9brand and weight). If we zero at 25, we're about 6" high at 100 and usually high at 200 also.
<br> I have to get out to the range and specifically document placement at the different distances. I've been more concerned with grouping at 200 than anything anywhere else.

Terry,
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<br> How high above the bore center is yuor scope center?
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<br> If you've got a 50mm or bigger scope, or just fairly high base/ring combination, it could explain your 6" high at 100 from a 25yd zero.
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<br>I recently put a scope on a flat top AR15 carbine in high rings. Sighted in at 25 yards, and I too was about 6-8 inches high at 100yards. I did some measuring, and realized my scope was 2.5" above the axis of the bore. At that point everything became obvious.
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<br> I rezeroed at 50 yards. It now hits about 2 inches high at 100yds, and dead on at 200 yards.
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<br>MM

http://internet.cybermesa.com/~jbm/ballistics/traj/traj.html
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<br>Here's a decent online ballistic calculator. MM

As I stated, I would forget about sighting-in @ 25 yds. You're just wasting bullets at that range.
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<br>Are you saying you're close to zero at 200yds and 6" High at 100yds? That doesn't make any sense if you're getting 2900fps with a .490 B.C. bullet.
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<br>Sight it in dead on at 200yds and then shoot a group at 100yds. I'm betting it will be 1.5 to 2.0" high. Good luck...

I'm shooting with a 3.5x10 - 50mm scope. So what does that do to sight hight. I have the lowest mounts I can with the 50mm objective lense. The bottom of the scope is barely 1/8", maybe 3/16 off the barrel.
<br> Now today, I sighted in my 30/30 at 200yds. Nice grouping, too. Barely an inch, with 2 of 3 touching in perfect center. When I went back to 100yds to see where it hit, I was 7" high from center. I didn't Chrony this one. I'm shooting 165gr Speer round nose and 35.0gr of IMR 4895. I brought it back down to 2" high at 100yds and went back to 200 with my last 3 bullets and they all shot under the target. The rifle is a Savage Super Sporter mdl 45 bolt action with a 22" barrel.
<br> I'll be shooting my 30/06 again tomorrow and I'll let you know where it hits at 200, 100, and 50yds.
<br> Just a thought, target hight would also change trajectory. I'll get out to the range early tommorrow and do some measuring of the shooting table and targets.
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Scope height has a LOT to do with bullet trajectory. Here are a few examples using your 168gr bullet with a B.C. of .490 and started out @ 2899fps;
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<br>1.5" scope height
<br>25yds.....100yds.....200yds
<br>-0.31".....+1.61".....0.00"
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<br>2.5" scope height (probably close to your gun)
<br>25yds.....100yds.....200yds
<br>-1.19".....+1.11".....0.00"
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<br>If you sighted-in dead on @ 25yds with a 1.5" scope height,you would be +2.85" high @ 100yds.
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<br>If you sighted-in dead on @ 25yds with a 2.5" scope height,you would be +6.0" high @ 100 yds.
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<br>This may explain your troubles. You have a large(50m/m) scope that is mounted high above your bore and magnifies the folly of sighting-in @ 25yds.

In the practical world, given all the variables, about all a 25 yard zero is good for is to get you on the paper at 100. Settle on one load, zero at or near the range you expect to shoot and then learn the ballistic characteristics of your chosen load in the event that you have to shoot at a longer or shorter range. Don't take the word of any book or program. Shoot your load with your preferred zero at 25 yard increments.

Cheaha,
<br> I just use 25yds to keep from wasting ammo. Once zeroed there, I go out to 200, so 200yds is my actual zero and when I come back to 100, I'm 6" high. This is the scope, then? My 44MM scope on another rifle, same modl ,does the same thing.