bullet drop ?

R

rebs

New member
I am shooting an AR 15 with a 16" barrel. I was under the impression that if you were sighted in at 50 yds you would be about an inch high at 100 yds and right on again at 200 yds. With my rifle shooting 55 gr dog town hp
bullets over 24.0 grs of H335 I am sighted in at 50 yds, right on at 100 yrs and about
1 1/2" low at 200 yrds. Does this sound right or do I have something wrong ?
 
There are so many variables. You just have to go shoot YOUR ammo in YOUR gun and see what happens. With different ammo or even your ammo in a different gun the results could vary. The best way to predict is to shoot your ammo over a chronogaph and plug the info into a ballistics program. Even then I'd still shoot it at varying ranges and see where it is hitting.
 
Personally shooting 30-06 I set up at 30-50 yards and sight in at 2 high, thus bringing me dead zero at 200. I would only assume the same for your round as well. Try it out and let me know. :)
 
rebs said:
I am shooting an AR 15 with a 16" barrel. I was under the impression that if you were sighted in at 50 yds you would be about an inch high at 100 yds and right on again at 200 yds. With my rifle shooting 55 gr dog town hp
bullets over 24.0 grs of H335 I am sighted in at 50 yds, right on at 100 yrs and about
1 1/2" low at 200 yrds. Does this sound right or do I have something wrong ?
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Yes, you're doing something wrong. You're letting your expectations get in the way of reality.;)
If that's where the bullet hits when you shoot, what else is there? It is what it is. That's why we don't shoot animals at ranges where we haven't shot paper, you don't know where that bullet will be until you've put one there.

CodyB65 said:
Personally shooting 30-06 I set up at 30-50 yards and sight in at 2 high, thus bringing me dead zero at 200. I would only assume the same for your round as well. Try it out and let me know.
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Have you ever tested that theory? Most any ordinary 30-06 round sighted 2" high at 50 yards is going to be much, much higher than "zero"ed at 200 yards.

According to JBM Ballistics:

For instance, all 2" high at 50,

A 110gr at 3,450 will 6.5 high at 200, a 150gr at 2,950 will be 6.3 high at 200, a 180gr at 2,750 will be 4.3 high at 200, a 200gr at 2,550 will be 3.3 high.

2" high at 30 would be MUCH higher at 200. That 200gr, 2" high at 30 would be 11 inches high at 200 and that's the LOWEST of the examples. That 180, 2.0" high at 30 is over 13" high at 200 and the zero is about 425.

Now, as I said, those are estimates and may not match reality exactly, which is why we have to shoot to be sure, but I wouldn't expect them to be off by more than an inch or so.
 
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If you have an iPad, just download the free app iSnipe. Just enter your bullet (choose off the list), input a velocity and where you want the zero to be, and it'll give you the full info you are asking for. I did that just yesterday afternoon when I mounted a scope on the grandson's 308 and needed to sight it in quickly.
 
with standard military M193 and carry handle sight height, 25 yards equates to a 200 yard zero, navy and airforce both sight in at 25(airforce uses meters) to get 200 yard zeros.

however changing the sight height, the velocity, bullet profile and weight all contribute to change what your bullet path will be, I'm guessing that 50 yards is near the apex of bullet rise and 100 is on the exact opposite side on the fall with that particular load in your particular setup.
 
Some theory doesn't pan out in real life. It can be close,...or not. I only use closer zeros for getting on paper at 100 yards, then fine tune it to where I want for longer zeroing from there. Seems more reliable than using closer zeroing.
 
Rebs, the trajectory is what it is. The bullet climbs to point x and then it starts falling. In general, a 25 yd zero is going to be close to a 200 yard zero. A 50 will definitely be low at 200.
 
Rebs in your opening post you said you were "right on at 100." How is zeroing at 100 going to change anything if you are already zeroed at 100?
 
I've always found that same thing with slower rounds from AR's. 50 yard zero equals close to 100 yard zero.

Now if zeroed at 25 yards, I am always high at 100 yards. Of course that goes for pretty much any rifle with a common modern chambering, save the 22lr.
 
Having tested 25-yard zeros on four ARs with different twist rates, different sights, different sighting plane heights, different barrel lengths, and four different bullet weights at 25 yards, 50 yards, 100 yards, and 200 yards, I'll say you zero your gun at whatever distance you plan to shoot it, to know for sure where it'll hit.

Otherwise, you're guessing, and no ballistics table or "this is the way we done it in the military" can be any guarantee of what YOUR combo will do in YOUR hands.

Denis
 
I have my ARs with irons and red-dots sighted at 50yds . What you explained your bullets are doing is exactly what mine do as far as drop . I'm with in a total of 1-1/2" difference from 25yds to 150yds . 200 yards is about as far as my aging eyes can shoot with out an optic so I love the 50yd zero for me .
 
Rebs in your opening post you said you were "right on at 100." How is zeroing at 100 going to change anything if you are already zeroed at 100?
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What I meant was I am going to fine tune at 100, I may need just 1 click up to be exactly center of bullseye and then record where I am at 50 and 200. My scope is mounted with high mounts on 1/2 inch risers because it is an AR and I needed the height to get a good cheek weld.
 
I think where some may be going wrong is trying to incorrectly apply the military's technique for weapons sighting on short ranges. The military can get away with that and achieve acceptably results due to a couple significant points.

First, for the most part, they are using M855 ball or M856 tracer ammunition, the ballistics of which they know well. Yes, other "specialized" units may be using other ammo (I was even handed a few "unique" specimens in my combat load last year), but for the most part, its either M855 or 856.

Second, they are using identical weapons. Every M-4 or M-16 variant is the same as others of its model. So, for instance, every M-4 has the same length barrel, twist rate, etc. Every M-16A2 is like every other A2. This is where MILSPEC comes in handy, it ensures standardization on multiple levels.

As such, the results of shooting the same ammo through identical guns will produce similar results.

Now, take any of that away, and your results will vary. The OP is using different ammo, and I also am assuming a different rifle, so the technique of sighting on shorter range using the military's assumptions is invalid. As mentioned, ballistics programs can help, but you need to get out there and shoot it to verify.
 
Don't know the BC or MV, but if a 50 yard zero resulted in 1.5" low at 200,
a 100 yard zero might be .5" low at 50 and 4" low at 200.
 
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