Long Range Shooting

[rebecca francis]

If you are interested in learning about long range shooting, this is an excellent article written by Doug Rosin.

http://www.rokslide.com/2012-01-09-...-what-is-your-maximum-effective-hunting-range

 

[Matt Cashell]

Thanks Doug for the great article! I enjoy long range shooting myself.

Overall, I thought it was a great rundown on long range shooting.

I could not agree more with Doug on the uselessness of arguing about the ethics of long range hunting. Everybody should know their own limitations, and not apply those to others. There are slob hunters of all types out there. My comments will be limited to long range shooting, and not hunting, for these reasons.

I hope Doug doesn’t mind, but I thought I could supplement my point of view on a few things in the article.

- On accuracy: Remember that the accuracy of your rifle is the outside group size, and the maximum you will be off from your point of aim at a certain range is HALF of your group size at that range. So, if you consistently shoot a 5 inch group at 400 yards, your can expect your bullet to land within 2.5 inches of your point of aim under those conditions, and at that range. In my experience a rifle that shoots around 1” groups at 100 yards is more than accurate enough to score consistent hits on game-sized targets out to 700-800 yards, if the shooter is skilled enough.

- Most factory rifles meet this accuracy benchmark, either straight out of the box, or with some DIY modifications, particularly bedding work. Some factory rifles border on WOW accuracy.

- I agree completely with Doug on consistent ammunition. This is more important, IMO, than super tight groups. If you are going to shoot long range, an accurate chronograph is a must. Even moderate deviations in muzzle velocity can have big consequences on your long range drops.

- Custom turrets are a really neat system, especially when you put the time into learning your load, as Doug instructed. As Doug pointed out, though, those turrets are for certain environmental conditions. My preference is to carry a booklet of my drops (and wind drift), and choose the right page for the actual conditions I am in, or if I know ahead of time that my elevation and temperature are pretty stable, I will tape the appropriate chart to the rifle, like Doug mentioned.

- I thought I would try my hand at explaining parallax error. A riflescope focuses two things in two different parts of the optical system. The diopter focuses the reticle, while the adjustable objective or side focus, focuses the image. When you set up your scope you use the diopter and focus the reticle sharp for your eye, and then leave it forever (or until your vision changes). then you use the image focus (AO or SF) and focus the image to the same plane as the reticle in the optical system. When the target is at different ranges, you use the focus adjustment to bring the image to the reticle’s plane, and again eliminate error. You can see parallax error by placing the crosshairs on a target and moving your eye around behind the eyepiece. The reticle will appear to move a little on the target.

An easy way to understand parallax error is to do the following:

1. Stand and arms length away from the wall.
2. Make a circle with your thumb and forefinger and hold it up halfway between your eye and the wall.
3. Move your head around while looking through the circle. Your hand will appear to move in relationship to the wall, but it is not moving.
4. Now extend your hand directly to the wall, and move your head. Parallax error is eliminated.

Not all scopes have an adjustable focus. Those that don’t have the scope adjusted by the factory so that the image is focused to eliminate parallax error at a certain range. Most standard non-focus hunting scopes are set at 100 yards. Some dedicated long range scopes are set at further ranges. Swarovski’s non-focus scopes with ballistic reticles are set at 200m. Zeiss’ non-focus Rapid Z reticle scopes are set at 300 yds. This minimizes parallax error at extended ranges, but allows for a small amount of parallax at 100m and in.

I think these long range non-focus scopes are great for long range shooting, as the parallax error is at a small enough level that you can still make your hits reliably, but you don’t have to mess with a side-focus knob or AO. Also, if your eye is centered behind the exit pupil (on the same axis) there is no parallax error regardless of the focus setting. (Think about the hand circle and wall test with your head sitting still right behind the circle)

On riflescopes:

While many, like Doug, prefer the close-up view high magnification scopes provide of the target, I don’t find high magnification is necessary or particularly beneficial for long range shooting. While it is nice for shooting tight groups at the range, high magnification magnifies everything. Including reticle movement, and atmospheric disturbance. I shoot regularly to 600 yards with a 2-7x scope. My dedicated long range rigs wear 4-12x and 4-16x glass. I had a 6.5-20x Mark 4, but found I preferred a little less magnification. Remember the target at 800 yards with a 10x scope looks like a target at 80 yards with open sights.

Objective size affects exit pupil, and not field of view. The field of view is primarily a function of eyepiece design. Larger objectives are necessary on scopes with high magnification, in order to give a sufficient exit pupil for low light performance. The lower the magnification, the smaller the objective can be to get a similarly bright image.

On turrets: turrets are calibrated in angular measurement, and either Minute of Angle (MOA) or milliradian (MIL) will work fine, as long as you know what you have, and calculate your drops accordingly. I actually prefer 0.1 MIL to ¼ MOA, and I like my clicks to be calibrated the same as my reticle.


Judging wind is the single biggest factor in making the long shot. It is a perishable skill that must be practiced and maintained.

 

[Kevin Root]

Very nice write up Bitterroot Bulls and Doug Rosin. Thank you.

 

[RosinBag]

Bitterroot any and all info is appreciated. I by know means know everything about long range shooting, probably just enough to cost me a lot of money and heart ache. All of Bitterroots comments are spot on and well written. Thanks for your input and hopefully others with good information on the topic will chime in.

 

[robby denning]

Great article Doug and thanks for contributing.

 

[HellsCanyon]

Great article and well written!

Bitterroot mentioned something at the bottom of his reply that I think is paramount to long range shooting/hunting. He mentions having his turret adjustments matching his reticle choice. No matter if you are shooting minutes (MOA), or MILS (Miliradian), you should choose an optic that has a matched reticle to your turret adjustments.

Say that you are coyote hunting and have your long range gun in your hands. You have a pack of three yotes coming in but they hang up in a meadow out there at 400 yds. You know that you'll likely have to engage any follow up shots at much longer distances than that initial 400 yard drop. In this situation I would use my reticle for holdovers instead of dialing to 400. First shot using my reticle I would use a 1.5mil holdover (100 yd zero). Second shot say at 500 would be 2.2mil holdover, third shot at 600 (if you are REALLY lucky!) would be a 3 mil holdover. Here is a picture of my reticle to help illustrate how the holdovers work.

Another reason it helps to have a match reticle is for your wind holds. We dial for elevation 100% of the time if shooting at a single target at a known distance and have time, but probably dial for the wind only 5% of the time (if that much, and never on game). I always work my dope cards up for a 10 mph wind knowing that the difference in wind is easy to calculate. 5 mph a simple 50% of your wind hold, 15mph is 150% of wind hold. This lets you dial your scope to your elevation, and use your reticle to hold for wind. Follow up shots are much easier to correct for as well and if you have to engage a second target at a different distance, you only have to adjust your elevation turret instead of both. Saves time.

Nothing replaces practice and beware that long range shooting/hunting can be one of the most enjoyable and expensive sports out there!

Mike