ZERO AT TWENTY FIVE.

[nastygunz]

ZERO AT TWENTY FIVE

By Mitchell Peters


Many deer hunters don’t do it at all, but for a lot of us sighting-in your deer rifle or at least confirming your zero is an annual October weekend event. Showing up at one of the supervised MDC ranges is as universal an experience for those participating, as the opening day of deer season itself. The range will be crowded, you will probably have to wait, and when your turn comes you will only get a hurried and hectic hour to take care of business.


I have been shooting for 33-years. I have had formal and informal training in many shooting disciplines. I have fired everything from a pea shooter to an 8” howitzer. I even use to know how to bore sight an M60A3 battle tank’s 105 mm main gun. I really thought I knew how to sight-in a deer rifle, or any rifle for that matter. I WAS WRONG! (I don’t have to admit that very often so take note.) I learned more in a two minute conversation with Bill Kunz, owner and operator of the Wil-Nor Hunt Club, than I had learned in the last 33 years. I had an epiphany, that is to say I had a sudden revelation of the elemental nature of the process of sighting-in a rifle for deer hunting.


Bill asked me what I was shooting. I proudly replied, “Grandpa Allen’s circa 1959, Winchester Model 70, in .243, with a John Unertl ¾ X 6 power externally adjusted, vintage scope. I explained, back in’59, Grandpa had a problem with feral cats and dogs eating his resident quail and ground hogs and raccoons were ruining his garden in rural southern Illinois. His Marlin .22 didn’t have enough reach so he went to his favorite gun shop in Terra Haute, IN and explained his predicament. They set him up with the technology of the time and he proceeded to eliminate his pests. Grandma said he would sit on the back porch with a tall glass of lemonade before dusk and never shoot more than once or twice. With twinkling eyes Bill said, “Nice gun, for deer hunting, ZERO-IN AT 25 YARDS” I incredulously replied back , no Bill I’m going to zero at 100 yards, what the H--- are you talking about. Bill said, “ it really doesn’t matter about the trajectory and ballistics, as long as it’s a center fire rifle with a velocity of about 2500 feet per second or faster” “FOR MISSOURI DEER HUNTING, ZERO-IN AT 25 YARDS!” That is the epiphany and it is as simple as that. 


I hadn’t shot this rifle since the late 1980’s and couldn’t remember the details except that at the time it was accurate and zeroed for 150 yards. I expected after three relocates and 25 years the sights were on the paper, but not really zeroed. The first thing to do was to check the screws. I went over all the screws at the trigger guard and on the forearm of the stock. I found the latter screw to be ¼ turn loose. Next I went over the scope ring bases and rings. All were tight. I was sure the rifle would print on the paper so I skipped bore sighting. Bore sighting is the process of setting up the rifle in a gun vice or with sand bags and looking down the bore at a target and aligning the sights on the same target. Correctly done, bore sighting will always get the first shot on the paper.


The rifle range at Wil-Nor was sunny, hot and humid. I was using Federal 100 grain POWER-SHOK soft point ammunition which I had purchased at Wal-Mart. I set up my portable rifle vise, a handy accessory which helps to mechanically immobilize the rifle. (It is a Sight Vise by Lohman, it was also purchased at Wal-Mart.) I took careful aim at the target 25 yards away and slowly squeezed the trigger…manipulated the bolt… and repeated the process two more times. The shot group was slightly high and to the left. I calculated the necessary adjustments and input them to the scope turrets and re-fired the group this time the ¼ inch group was centered in the bullseye. I moved the target to 100 yards and re-fired a three round group. It had opened up to about an inch and a half and about 2 ¾ high and just slightly to the left. I gave the scope one click to the right to fine tune the sights. Nine bullets later and I was finished. FOR MISSOURI DEER HUNTING, ZERO-IN AT 25 YARDS! Then fine tune the windage only at 100 yards.


By now the skeptics, doubters, and competitive high power shooters are thinking I’m crazy and asking questions. How can this be? How does this work? Why don’t you sight in at 100, or 150 yards? Read on. In Missouri, the majority of white tail deer are killed at less than 100 yards, due to brush, hills, and terrain, few deer are killed between 100 and 200 yards, and rarely at distances beyond that. The conventional wisdom for a chest shot on a deer is accepted as a 12” circle but for this article lets assume it is only 8”. Deer are 3-dimensional, alive and moving and have little in common with a two-dimensional paper target. The objective is to place a bullet anywhere within an imaginary 8” circle in the deer’s chest area. I have never seen a live deer imprinted with an 8” bullseye target however I did see such a thing in a cartoon where two deer were talking. The punch line was “Bummer of a birthmark, Dude!”


Next let’s pick eight of the most common calibers and cartridges used to deer hunt in Missouri and determine their point blank range with a zero of 25 yards. I determined the selection of cartridges by the semi-scientific method of supply and demand. I visited Wal-Mart in Eureka, MO, noting what ammo was on sale in bulk at the deer hunting gear isle. From smallest to largest the calibers are: 1).223 Remington, 2) .243 Winchester, 3) .270 Winchester, 4) 7mm Remington Magnum 5) 7.62 X 39, 6) 30-30 Winchester, 7) .308 Winchester, 8) 30-06 Springfield. I had my friend Jeff Chosid a nationally renowned highpower competitive shooter, and author, run ballistic data for me using Sierra Infinity Ballistics software. Jeff also has a small business called C.A.B. Designs that produces standard and custom wind charts. Check them out at windcharts.com. The ballistic charts were plotted by Jeremy Hogue.


First on our list the Remington .223 , a varmint and military cartridge, at 700 fps faster than our 2500 fps threshold, we would expect that it shoots flat and it does. Using a 55 grain bullet and a 25 yard zero, the bullet is never 3 ¾ inches above or below the point of aim out to 300 yards. The bullet also crosses zero at just past 250 yards. Therefore the point blank range for the .223 is from 0 to 300 yards. To kill a deer you simply aim at the imaginary 8” circle and pull the trigger, with no hold over or under to worry about. Before you trade in your old .35 Remington remember that while the .223 shoots flat, it is still only a .22 caliber. It is the minimum sized, legal cartridge for deer, and many experienced hunters however would consider it a poor choice.


The Remington .243 is a much better pick. Based on the .308 this 6mm shoots flatter than the .223 and with almost twice the bullet weight at 100 grains. With a 25 yard zero, this cartridge also has a 300 yard point blank range. The maximum rise of the bullet is under 3 ½ inches at 150 yards and just below 3 ¾ inches at 300 yards. From varmints to deer this caliber is an excellent choice, especially if low recoil is an important consideration.


The old and reliable .270 Winchester is also an excellent choice. It is flatter shooting than it’s parent the ubiquitous 30-06, but not as effective on big game like elk and moose, which is not a problem in our state. Using a 150 grain bullet, and a 25 yard zero we have a point blank range of over 300 yards. The top of our trajectory is 3.83 inches at 150 yards and 1.40 inches low at 300 yards.


The 7mm Remington Magnum has much more power than needed for Missouri’s whitetail hunter but its flat shooting and long range capability make it an excellent “bean field rifle”. Using a 25 yard zero and firing a 150 grain bullet the trajectory is very similar to the non magnum 270. This cartridge also has a point blank range of 300 yards with the maximum bullet rise of 3 ¾ inches and a maximum fall of slightly more than 1 ½ inches. At 300 yards. Perhaps more interesting is there is no significant advantage over the old 270 except the potential for shooting slightly heavier bullets.


The next two calibers I will talk about are the venerable 30-30 and the 7.62 X 39 Russian. Both these cartridges when compared together are within fractions of an inch on the ballistic table and both are a little below our 2500 fps threshold. The 30-30 was designed before 1900 and the 7.62 X 39 was designed for the SKS carbine in 1945. Both cartridges, the 30-30 with a 150 grain bullet and the 7.62 X 39 with a 123 grain bullet are adequate for a point blank range of 0 to 200 yards when sighted in at 25 yards. Additionally both cartridges are also near zero at 150 yards and never rise more than 2 inches above zero.


The .308 Winchester and the 30-06 Springfield are as similar to each other ballistically speaking as the previous two cartridges. Coincidentally the .308 is also about 50 years younger than the 30-06. These cartridges were designed for the military and both have proven records as big game takers in North America. Both offer a wide variety of factory loaded ammunition in different bullet weights and styles. With a 25 yard zero and bullets between 150 and 165 grains both will have point blank ranges of 0 to 250 yards.


In researching this article I not only proved a 25 yard zero works, I discovered several interesting points. I never would have believed a 30-30, and a 7.62 X 39 would shoot flatter at 200 yards than a 7mm Rem. Mag, or a 243 at 300 yards, but they do. I also never realized how ballisticlly similar the following cartridges are: a 30-30 and a 7.62 X39, a 270 and a 7mm Rem Mag., and a 308 and a 30-06. Furthermore I do not see much advantage of a 7mm Rem. Mag. over the much older and less glamorous 270. Now here are at least four separate arguments you can bring up at deer camp 2005, just make sure you have this copy of Missouri Deer Hunter Magazine to prove your point. My thanks to Bill Kunz for the inspiration and motivation to write this article.

[HaMeR]

Here where I hunt I could use that theory & save tread at the range. Hard to get a clear shot out to 100yds here.

[Hawks Feather]

Here where I hunt I could use that theory & save tread at the range. Hard to get a clear shot out to 100yds here.

Here too Glen, but we can't use any of those calibers.  Someone needs to see if it holds true on straight wall rifle cartridges.

Jerry

[pitw]

I've used 25 to sight in for ever and the buddy's are always amazed at how it works.  No surprise they found the 243 to be so wonderful.

[HaMeR]

I know where my 357 hits at 100. Maybe I'll dial it in at 25 for a quick looksee.

[Carolina Coyote]

Sounds like a good method for getting your firearm Zero in, I never wait to October to check out my rifles as I shoot all year long and hardly ever have to do any adjustments unless bullet change or powder change but I like the 25 yard idea and will for sure use that when starting from scratch, Thanks for sharing.cc

[nastygunz]

 I dusted off that article because crow season opened here today and even though it is hot and humid as hell I can smell fall in the air! The old farmers almanac says we are supposed to get a bitter cold winter this year.