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Discussion Starter · #1 ·
I would like to get some opinions on the best distance for zero when dialing in a 582 series Mini-30, 18" barrel with iron sights. I have a factory rear sight and a mo-reaper front sight/muzzle brake. I believe the front sight height is 1". I checked out a few ballistics calculators and 25 to 27 yards seemed like a good choice. Fairly flat from 25 to 100 yards. I am only interested in 0 out to 125 yards as far as range goes. That's about as far as these old eyes cans see and that is pushing it a bit. I usually shoot 123 grain FMJ's and SP's. Thanks in advance for any input.
 

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That is distance I have always heard to sight with 25 yds.
 
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Yup 25. It puts you back at zero at about 200. You'll be about 2.5" high at 100.
So here is a tip: when you zero at 25, split the bulls with the top of the sight. At 100yds, snow cone the target will be about right.
 

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Discussion Starter · #4 ·
Thank you kindly for your responses. Funny thing, I was researching this last night and I read many times that sighting in at 25 yards would put me back on zero at 200 yards but the ballistic calculators I use showed a drop of close to seven inches at 200 yards....:blink:
 

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Discussion Starter · #6 ·
I am going to zero the rifle at 25 yards and I agree with you about KingANuthin's post. Great tip and I will use it. I am just curious about the ballistic calculators results. Point Blank is one of the calculators I use. It shows a 7 inch drop at 200 yards with a 25 yard zero. I read many posts on many forums that zeroing at 25 yards with a 123 grain 7.62x39 projectile will cross zero again at 200 yards. I am new to the science of ballistic calculators so please excuse my ignorance on the subject...:)
 

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I use Point Blank. I have everything on there and have printed out ballistics pages and put them in plastic which I carry with me in a little book. I can't remember all the numbers since I shoot every thing from a .22 to a 30.06. It is a great program for free.

Looking at the 7.62 round and ballistics, I would zero at what your farthest iron sight distance is going to realistically be. Practically, it might be from 50 yards to 100 depending on your sights and eye sight.

From purely a ballistics of bullet viewpoint, yes it will be 7 inches low at 200 yards. However, if you factor in a scope or other sight height you can see that the bullet trajectory starts that distance below parallel(degree of up angle on the muzzle) so the bullet trajectory changes. A 2.5" scope height with a 50 yard 0 = 1 inch high at 100, 0 at 150 and 3 inches low at 200. You need to know how high above the bore your sights are to know what your hold overs need to be.
 

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Discussion Starter · #8 ·
Thanks for the response hattarod. Zeroing at the farthest distance I would be shooting is how I have always sighted my rifles in through the years. I have just recently been trying out the ballistic calculators.
 

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I am going to zero the rifle at 25 yards and I agree with you about KingANuthin's post. Great tip and I will use it. I am just curious about the ballistic calculators results. Point Blank is one of the calculators I use. It shows a 7 inch drop at 200 yards with a 25 yard zero. I read many posts on many forums that zeroing at 25 yards with a 123 grain 7.62x39 projectile will cross zero again at 200 yards. I am new to the science of ballistic calculators so please excuse my ignorance on the subject...:)
Something's up with that result. 7" low at 200 yards with a zero at 25 would be the worst bullet ever designed and wouldnt be bothered to even begin production of.
That's like bow and arrow trajectory
 
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Yeah, that sight height looks low. You'd be about 7" low at 200 if you zeroed at 100.
 
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Ok.... Found some of my paperwork.. Scoped I was looking at 25/200 zero. Sorry, it's been a while since I've shot. Damn shortages.
On my irons I have about what you got there.. I've zeroed at 50, and snow cone at 100, and then it starts to take a plunge..
The plunge really begins after 225 with a 1" scope on med rings.
 
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Discussion Starter · #13 ·
I am going to go with 30 yards as my zero. This gives me a fairly flat trajectory from 25 to 100 yards. With my sight height and limited vision this would work the best for me. Where I hunt you don't get much more distance than that anyway. So it will work out well I believe. Thanks to all of you for your input.

 

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Discussion Starter · #14 ·
Well, I am going to ask a question that might seem ignorant but I just want to clarify my calculations because as KingANuthin posted above these ballistics are not much better than a bow and arrow. When the ballistics calculator asks for the sight height it is referring to the distance between the center of the muzzle and the top of the front sight, correct?
 

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That 25 yard O coming back to 0 at 200 yds is more of an AK /SKS thing. Does not work for a Mini 30. AK/SKS have a battle sight setting. Rear sights on AK are adjustable for height. By sliding the rear sight forward to increase height or back to degrease height.
At the rear of the AK sights is a ledge you can pull the sight back to. It pretty much equals the height that the sight would be at if it was set to the 200 M position. That is the battle setting. That is the position AK/SKS are sighted in at 25M then come back to 0 at 200M. Reason being, in the heat of battle a solder does not have to worry about moving the rear sight to compensate for distance. Pull it back to the battle setting. Aim just above the belt buckle, and you are good to make a torso hit out to 300M.
Mini 30 sights are fixed and not adjustable for height/distance. So that 25 yard 0 thing does not work for them.
Just 0 in at 100 yards and call it good.
Or IIRC For a Mini 1" low at 25 yards will get you close to 0 at 100.
 
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Well, I am going to ask a question that might seem ignorant but I just want to clarify my calculations because as KingANuthin posted above these ballistics are not much better than a bow and arrow. When the ballistics calculator asks for the sight height it is referring to the distance between the center of the muzzle and the top of the front sight, correct?
Typically......yes. Your line of sight is an imaginary line between the rear sight, front sight to your target. This is a straight line in relation to the bore or axis of your barrel.

Bullets do behave just like a bow and arrow or vice versa. Gravity is constantly pulling your projectile back down to earth.

The speed and angle at which your projectile is launched versus the resistence it encounters will depend on where it falls back to earth.

Your velocity is measured in feet-per-second (FPS) and the ballistic coefficient deals with how well the bullet reacts with the resistence of air and gravity.

Sectional Density tells you the performance as far as penetration along with bullet design.

It's when your projectile meets your line of sight that your gun is "zeroed"

Whether you "zero" at 100yds, 200, 300 or more or set your sights for an approximation thru several ranges as MPBR, knowing where your particular bullet is going to be at all ranges gives you a leg up when shooting a target.

If you want a flatter trajectory change to a different cartridge. 7.62x39 is not a great cartridge for ballistics, it's comparable to the 30-30 with pointy bullets.
 

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The ballistics you will actually experience out of the gun depends on the sight height. With the 7.62 by 39 round a longer zero means you are going to pass zero twice so you have to take that into account when you are sighting in if you start at close range like 25 yards. You want to catch the first zero 25 and the second when you move to 100.

I have my 30 zero'd at 150 yards with a 3 x 9 up at around 2 inch sight height. That puts me an inch high at 100 and 3 low at 300 so its easy to remember if I'm in the woods hunting and easy to hunt with out to 200 yards. 1 at 100, 3 at 300.

That is the typical ballistics for a 7.62 by 39. It drops like a rock past 200 yards but at 200 it is still carrying just over 1000 fps energy and with a relatively slow 30 cal bullet that is good for what it was designed to do.

Oops: its 1 up at 100, 3 down at 200
 

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Discussion Starter · #18 ·
I really appreciate all the great info. I am retired with plenty of time (I hope) and I did a lot of research on the 7.62x 39 caliber and the Mini-30 before I made a purchase. I am very happy with the choice. I knew the set up was not a long range tack driver. I ran across the Point Blank ballistic calculator (and I was off to the races) and got interested in the 7.62x 39 ballistics. I wanted to find the best zero to achieve the flattest trajectory out to 100 yards. A lot of the info on the net said 25 yards would hit zero again at 200 yards. The ballistics calculator did not show the same results. The sight height on the Min-30 is the reason for this. I figured I would ask the well informed people here on the Ruger Mini-14 and Mini-30 thread and see what the general consensus on the best zero for sighting in the Mini-30 would be. It seems that 30 yards is going to give me the flattest trajectory within 100 yards max for the type of bullet that I use. The Mini-30 is a great gun and is exactly what I was looking for when I purchased it. I have had no problems with the gun itself it shoots everything I have fed it and it was accurate out of the box. I did have a problem with a 20 rnd factory mag but it has been resolved. Thanks again for all the great info.

4/18/13, 25 yrds. 7.62x39, 122 grain Tula FMJ

 

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That 25 yard O coming back to 0 at 200 yds is more of an AK /SKS thing. Does not work for a Mini 30. AK/SKS have a battle sight setting. Rear sights on AK are adjustable for height. By sliding the rear sight forward to increase height or back to degrease height.
At the rear of the AK sights is a ledge you can pull the sight back to. It pretty much equals the height that the sight would be at if it was set to the 200 M position. That is the battle setting. That is the position AK/SKS are sighted in at 25M then come back to 0 at 200M. Reason being, in the heat of battle a solder does not have to worry about moving the rear sight to compensate for distance. Pull it back to the battle setting. Aim just above the belt buckle, and you are good to make a torso hit out to 300M.
Mini 30 sights are fixed and not adjustable for height/distance. So that 25 yard 0 thing does not work for them.
Just 0 in at 100 yards and call it good.
Or IIRC For a Mini 1" low at 25 yards will get you close to 0 at 100.
It does on a scope with medium rings. It's about the same height as the AK sights. I zero mine at 25, an if I go 11 clicks (1/4 moa per) at 100 yards its good. It seems about right at 200, but it is 4-6 inch groups at that distance.
 
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A lot of the info on the net said 25 yards would hit zero again at 200 yards. The ballistics calculator did not show the same results.
Don't know if you read my post above but. I will repeat. The sight in at 25 yards and back to 0 at 200 is an AK/SKS thing. It does not work for a M30 with stock iron sights. AKs have a Totally different sight set up than a mini 30.. (And a lot better IMO) Stock Iron sights on Minis are crap.
 
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