AR 7.62x39 zero distance

C

Chrismohler12

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I recently obtained a 7.62x39 in the AR platform. After working out the kinks with the firing pin and finding reliable magazines and buying 20 of them, I am ready to zero it in and start having fun. I intend on using this rifle for deer hunting in the 25-150 yard range. I am aware some don't like the cartridge for this use but I have seen my father take a lot of deer with the 7.62x39 and they go down hard. I have heard people say to sight it in at 25yds and that would give a fairly flat trajectory up to 200 yards. That seems short to me. Any opinions are appreciated. Thanks
 
people say to sight it in at 25yds
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Don't do that.
Because of the height of AR sights, that might put you 6" high at 150 yards.
Sight in at 150. Or an inch or 2 high at 100.
 
Do the 25 for starters and then see how well it shoots at 50, 75, 100 and as far as you need to go.

But you might want to buy good ammo. The Tula I use in my scoped SKS (bought it that way) likes to dance a bit. One inch to the left and then to the right at 25 yards. Brass cased hunting loads seem to hold better but I don't remember the brand I used.
 
"But you might want to buy good ammo."
For hunting, give the Hornady SST ammo a try.
The round is a 150-175 yard deer killer AT BEST-sight in accordingly.
 
Sight in at 100. How high will depend on the bullet/ammo you're using. Hornady's 123 gr SST Steel Case(just an example. Isn't reloadable.) sighted in 3.5" high at 100 is on target at 200(energy's far too low at that distance for deer.), 14.8" low at 300. Federal's 123 grain SP sighted in 1.5" high at 100 is 6.8" low at 200 and still too low in energy.
It's absolutely essential you know the ballistics of your hunting ammo.
What ammo's your pop using?
 
The "25 yards" thing is a military battlesight zero for the M16 rifle, with the rifle zeroed at 25 meters, you can hit a enemy (man sized target) out to 300 meters by holding dead on. Details here: http://www.usaac.army.mil/amu/assets/zeroing.pdf

That is simple a MPBR zero for that rifle and ammo combination. Keep in mind, the military is less concerned with a clean humane kill that simply a hit on target, so the battlesight zero is not really well suited to hunting.

Your rifle is not 5.56 NATO, so your best bet is to use a ballistics calculator, measure your sight height (over bore center-line) and run some numbers.

JBM is excellent, and has a extensive database of bullets: http://www.jbmballistics.com

Play with it, find out what works best for your needs, and when you decide what you want to do, reality test in in the field. If you numbers say a 32 yard zero will put you 2.9" high at 100 yards and .3" low at 200, test for yourself and see if that is true, and adjust accordingly.

Pay attention to the sight height measurement, it is important to getting a correct trajectory from any calculator.
 
sighted in 3.5" high at 100 is on target at 200(energy's far too low at that distance for deer.)
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Really? Ballistic charts say he still has >1000 ft/lbs out to 300 yds. Am I missing something?
 
"I have seen my father take a lot of deer with the 7.62x39 and they go down hard."
I've seen around 10 deer shot with the 7,62x39 and NONE "went down hard". In fact most showed very little indication of being hit.

"Really? Ballistic charts say he still has >1000 ft/lbs out to 300 yds. Am I missing something?"
No 7.62x39 ammo that I'm aware of has 1000 ft lbs of energy at 300 yards.
 
No 7.62x39 ammo that I'm aware of has 1000 ft lbs of energy at 300 yards.
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This. Everything I am aware of is ~125g at ~2350FPS. They have ~1500 ft-lbs of energy at the muzzle, around 1150 at 100 yards, and depending on the bullet, will fall below 1000 fps around 140-150 yards.

To get 1000 ft-lbs at 300 yards, with that little bullet, you would need to launch them around 3000 FPS, and that isn't happening safely, if at all in that little case.
 
I intend on using this rifle for deer hunting in the 25-150 yard range
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The vital (heart/lung) area of the average deer is 10-11 inches. Play with some free on line ballistic charts for your bullet and velocity to get a drop chart.

Study the chart until you find a zero where the shot would be no higher the 5 inches and drop no more then 5 inches.

That should tell you where to zero the rifle.

Don't take these number for gospel. I don't own a 7.62X39. I just use the 123 grn bullet at 2300 fps and a sight height of 2.5 inches and plugged the numbers into SHOOTER on my phone.

Sighting in the rifle at 225 yards it will be 4.9 inches high at 150 yards and 5 inches low at 280 yards.

I believe in sight the rifle in at the distance you want in your zero, in this case I would sight it in at 280 yards.

But for info a 280 yard zero would put your round 1/10th of an inch low at 25 yards.

Again don't take these numbers a FACT, I don't know your bullet, its velocity or the sight height above your bore. But if you have that info, you can get pretty close.

If you are sure you wont be hunting past 150 yards, I'd shrink that 10-11 inch vital area where your zero would be somewhere short of 150 yards.

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EDIT: Don't get hung up on energy. Different bullets work different ways, meaning some are designed to come apart disturbing the nervous system of the critter, some are suppose to mushroom to a point and hold together. Both require a X velocity. Find a bullet that is designed to work at your retaining velocity at your target.
 
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I sometimes take my AR in 7.62x39 for deer hunting when I'm in dark timber.

I sight in for 100; I can hold a bit under if less than that and I seldom have a shot past that distance where I hunt. If I were smarter, and had a range of my own, I would sight in for 60 yards and just hold straight on if farther than 40 yards.

I don't sweat energy numbers at 200 or 300 yards, b/c I won't take a shot that long. 7.62x39 will have enough energy to kill a deer, if you hit it in the right area.

Good luck out there.
 
If your shot distances are 25-150 yards yards, I don't see any reason to zero for 200 yards. Zero at 100 as Scorch said. That will put you about an inch low at 25 yards and 1.75 inches low at 150 yards. You will be within a half inch to spot on from 45-120 yards.
 
x39 on deer

I don't own a AR in the x39mm cartridge, but I do own a Mini30 and a Ruger Mk77-II so chambered and have been hunting them on our southern whitetails for years. Likewise, bamaboy shot a couple with the bolt rifle before he moved up to something bigger (like my Hog Rifle). The two biggest bucks I have ever taken were both killed with the 77MkII, one the past season and another about 7 years ago. About half the deer have dropped at the shot, the other half run the typical short death spring before tumbling. Shot distance has been always under 100 yds, many about half that. I liken it to hunting with a 30-30,and do not ask any more of it. I hunt my x39mm rifles selectively.....their short length and light weight lend themselves to long hikes, to steep and thick locations, and often toting a climbing stand as well. I cannot see past 100 yds in these spots...the little rifles do fine (so does an older .44 Ruger carbine too). HUnting ROWs and green fields....I take a different rifle.

Once I am on paper at 25 yds, I move to 100 yds and zero my x39mm rifles "ON" at that distance. I have no doubt the x39mm will kill farther than that, and might benefit from a slightly higher zero, but I believe the 100 yd zero puts my trajectory close enough to my line of sight for the distances I'll be shooting, to be very practical. If I can see a hole through the brush in the scope, the bullet will be very close to my line of sight, not overly above or below and clip a limb and spoil things.

All the deer we've killed have been taken with my reloads using the now defunct .30 cal 135 gr Sierra 135 gr Pro Hunter bullet. As the last of these are in my ammo boxes now, I'm searching for a replacement. I bartered for some 125 gr Hornady SST's and am considering those....Speer makes a .30 130 gr Flatnose, and I've loaded some 150 gr 30-30 Flat noses, but only as an experiment.

One thing for sure, there are better bullets than the import HP's, spring for quality ammo.
 
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