Long range rifle shooting questions...


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IrvJr
November 6, 2007, 08:58 AM
Hi All,

I'm fairly new to rifle shooting. Up till recently, I've mostly shot rimfire rifles, carbines, and shotguns (clay sports). I recently bought a Remington 700 in .223 and with some help from THR, I was able to successfully mount a Leupold scope on the rifle and sight the scope in at 100 yards.

I was only using inexpensive Remington Ammo (55gr, fmj from walmart) but I got some nice groups the other day with the gun/scope combo at 100 yards. Being a novice when it comes to rifles, I had some questions about long range shooting...

1. when I sighted my scope in, I initially used the 25 yard range. When I switched to the 100 yard range, my rounds were several inches (maybe 4 to 6 inches) high. Is this normal? If I sight my .223 rem gun in at 25 yards, do I need to crank up the elevation 4 inches if I'm going to shoot it at 100 yards?

2. I'm planning on shooting the gun at longer ranges (200,300 yards). How much bullet drop can I expect from 100 to 200 yards? From 100 to 300 yards?

3. If I sight my gun in at 100 yards, then want to shoot at 50 yards, will there be a noticeable difference in elevation?

4. I've heard about ballistic tables that help long range shooters calculate the bullet drop at various distances - where can I get these tables and how are they used?

Thanks in advance.

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Double Naught Spy
November 6, 2007, 09:25 AM
1. Yes, but it depends on how high the center of the scope is over the center of the bore. Your scope is probably 1-1.75" over the bore which means for the shot to hit at 25 yards, you needed an upward cant of the barrel (assuming the scope is level) for the trajectory of the bullet to carry it to the aim point of the scope. Since .223 is a light and fast projectile, it is going to carry through 25 yards and continue to climb for quite some distance before starting to descend. So sure, you could be several inches high at 100 yards.

Don't sight in your gun at 25 yards if you plant to shoot 100, 200, 300 yards.

2. You need a good ballistics calculator such as is available various places online. You can search this forum or google "ballistics calculator" for free online calculators.

3. If sighted at 100 yards and shooting 50, the difference in elevation will be about half of the distance between the bore center and scope center. So if your scope is 1.5" over the bore, then at 50 yards, impact will be about 0.75" low. Note that this is a rough approximation, but since the amount is so small, it is close enough for the field.

HOWEVER, the same is not true for sighting in at 200 yards and then shooting 100. You shoudl have climb out to about 100-150 yards before your rounds starts to descend (depending on load, bullet weight, angle of the bore relative to the scope).

4. See #2.

azredhawk44
November 6, 2007, 01:55 PM
A great program that will help you see how all these variables come together is called "PointBlank" and is available as a free download if you google it.

With a .223 moving at about 2700fps, a 25 yard zero will be high at 100 yards and come back down to zero again around 225 yards. All this depends on bullet weight and ballistic coefficients, but PointBlank will show you exactly how it all interacts.

mpmarty
November 6, 2007, 03:11 PM
In addition to the above comments, when shooting at long yardages, you will also have to factor in wind drift, direction of rifle twist, rate of twist as at long distances, the forward velocity decreases and so does the rate of twist until it reaches a point where it no longer stabilizes the bullet. Longer heavier bullets in slow twist rifles exacerbate this problem. Elevation above msl (Mean Sea Level) and barometric pressure also effect exterior ballistics as will temperature and humidity. All in all true long range shooting is addictive, go out and have fun.:)

Zak Smith
November 6, 2007, 05:06 PM
Read the LR shooting series of articles linked in my signature below:

TheGunGuru
November 6, 2007, 10:10 PM
I don't want to make any of you guys/girls mad, no one has said any thing wrong...however for the beginner, with little practice in rifle shooting, the best thing to do is get some paper and shoot. With a little time and 40-50 rounds you can work the problem out.

I have a savage .223 that I have sited in for 100 yards, as you should do also, and it is not very difficult to shoot out to about 600 yards with some practice. Begin with a paper at 150 yards, with your gun already zeroed at 100, shoot a few times, 3-4, and measure how far the bullets dropped. Move a target to 200, 250, 300... repeat. Keeping going until you reach about 600...and thats about the most you will get with Wal-mart ammo and a Remington 700 but 600 yard shooting is still pretty good...and VERY fun.

Swampy
November 7, 2007, 07:42 AM
IRv,

Good advice all around from the guys.....

BTW, shooting at 100 yards is not "Long Range"..... "Long Range" rifle shooting, by NRA nomenclature, does not BEGIN until 800 yards.....

Anything out to 400 yards is considered Short Range, 500 & 600 are Medium Range, 800 to 1000 yards is Long Range.

Good luck with it....

Best,
Swampy

2007 NRA Missouri state "Medium Range" Service Rifle Champion....
.... with an M1 Garand. :D

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