Posted: 1/8/2010 4:47:21 AM EDT
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Here is a question for those with knowledge of such things. I am the "armorer" for all my friends who hunt. Including myself We use the following calibers.
.243 Winchester (2) .308 Winchester (3) .30-06 (3) .270 winchester (1) .280 Remington (1) .300 Winchester Magnum (1) My Range behind my house is only 25 yds. I used that as my zero to point of aim Using 2 different Ballistic calculators I thought everything would be good, but I was surprised at the results. http://www.handloads.com/calc/ http://ballisticscalculator.winchester.com/ Both these Calculators Told me that with a 25 yd zero that the equivalent zero would be close to the following. .243 200yds .308 215yds .30-06 230yds .270 235yds .280 235 yds .300 Win Mag 310yds Except for the .300 Win Mag the max POI above POA between 25yds and the listed numbers above should have been no larger than around 3 inches. the .300 win Mag would have been a little over 4 inches at 200yds. After the first hunting trip one of the best shots of the group completely missed at 150 yds. with 5 shots. He noticed he was hitting way high based on some impact of the rounds on trees. He did some Kentucky windage and hit a doe square in the brain. He decided to check his rifle after the trip and at 100 yds. His and his sons .30-06 were hitting about 6 inches high at 100yds. I rounded up the other guns and went to a buddies house where I could get 100yds and every one of them was hitting 5.5 to 7.5 inches high at 100yds. Everything was re zeroed and we had a fairly successful year. Yes most of these are reloads. Loaded too as close to standard as I can get based on my Chronograph. Yes I checked scope height above the bore. Is there something I did to make it so far off from the calculators? How can these calculators be so far off? And has anyone else experienced this? |
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So you zeroed the guns at 25 yards for YOU and then handed them to someone expecting to make headshots on deer at 150+ yards with no check of zero at that range? If he had attempted a body shot he would have at least spined it... Did your friend know you only had 25 yards to zero at the time?
I can certainly understand the limited range that you have to work with, but i would have found SOME way to check my zero at a more appropriate range. I'm in the similar "armorer" situation as you with my dad and several of our friends, but i always zero them to 1-2" high at the 100yd range. We mostly shoot 30.06, with a couple .270's. This gives us minute-of-heart zero within 200 yards. I know you did the best you could with what you had, i just think it's kinda irresponsible of your friend to attempt a headshot at that range without checking zero at distance if he knew you only had 25 yards to work with. If he didn't know you zeroed at 25yd, well then... he probably should have... I just hope he wasn't mad at you for trying to him a favor... |
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For what it's worth... When I started in with rifles, I had two different guys help me with scopes on my first high powered rifle. The first guy wanted me to sight in first at 25yds hitting 2" high and the other guy wanted me to hit dead on at 25yds. Both said that I should be hitting paper close to 2" hight at 100yds.
Guess what? I was every bit 6" high on the one sighted dead on at 25yds. One guy, the 2" high guru, was a police officer of 28yrs. He blamed the shitty-ness of the Aetec Scope and that every scope requires LESS clicks at 25yds than 100yds and he knows all, so me re-peating what I'd read and heard on the subject was shrugged off... The other guy was an excellent rifleman and reloader, and admittedly said he'd brain farted on the deal. No big deal and I respect the humbleness. So you aren't the first and won't be the last. I don't need to re-sight at 25 yds now unless I change or re-mount a scope, but when I do I sight in 2" LOW at 25yds and then go to 100yds to dial it from there. |
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Quoted:
So you zeroed the guns at 25 yards for YOU and then handed them to someone expecting to make headshots on deer at 150+ yards with no check of zero at that range? If he had attempted a body shot he would have at least spined it... Did your friend know you only had 25 yards to zero at the time? I can certainly understand the limited range that you have to work with, but i would have found SOME way to check my zero at a more appropriate range. I'm in the similar "armorer" situation as you with my dad and several of our friends, but i always zero them to 1-2" high at the 100yd range. We mostly shoot 30.06, with a couple .270's. This gives us minute-of-heart zero within 200 yards. I know you did the best you could with what you had, i just think it's kinda irresponsible of your friend to attempt a headshot at that range without checking zero at distance if he knew you only had 25 yards to work with. If he didn't know you zeroed at 25yd, well then... he probably should have... I just hope he wasn't mad at you for trying to him a favor... The head shot was a fluke. Yes they all new I zeroed at 25 yds. Each one had shot their respective rifle at 25 yds. He was going off the information I had given him based on the information I got from the Calculators. I have already taken responsibility for the incorrect info. Yes I have learned an important lesson as regards to Zero, however the question still remains about the calculators. I will not take a hunting rifle out again until it has been zeroed at 100 yds on paper not on the calculator. I will also advise all the people I hunt with the same. Next year before the season I already have it set up to get everyone their rifle zeroed at 100yds. |
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Not trying to flame as I was in the same situation last year. Some friends had zeroed their guns at 25 and then couldn't hit a deer at 200 yds. We went to a 200 yd range and they were all shooting 6 to 7 inches high. Add cold weather clothes and the excitement and shaking of buck fever and they didn't have a chance. I'll tell you like I told them, Why practice layups when your gonna be shooting 3 pointers.
Glad to hear yall put some meat in the freezer. |
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Quoted:
Not trying to flame as I was in the same situation last year. Some friends had zeroed their guns at 25 and then couldn't hit a deer at 200 yds. We went to a 200 yd range and they were all shooting 6 to 7 inches high. Add cold weather clothes and the excitement and shaking of buck fever and they didn't have a chance. I'll tell you like I told them, Why practice layups when your gonna be shooting 3 pointers. Glad to hear yall put some meat in the freezer. Not a flame at all. I learned an ever important lesson that I should have already known. Don't trust what is written until verified in the field. |
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Let me give an example of my rifle.
.308 winchester 150 gr Hornady SP 44.4 gr Reloader15 2720 FPS Scope height above bore 1.6 inches 25 yd zero by the calculator 25 yds hitting point of aim 100yds 2.89 inches above point of aim reality with 25 yd zero 25 yds hitting point of aim 100 yds 6 inches above point of aim. |
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The one problem with using a 25 yard zero is that any errors amplify them selves greatly as you go down range.
If you play around with the calculator a bit a 1/2" off at 25 yards changes you from 2" high to 5" high at 100 yards. Not saying you weren't properly zeroed at 25 yards, just saying any errors magnify themselves as the distance goes out. You are correct you need to verify at distance if at all possible. |
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You say you checked the scope height above the bore. That's fine, but the bullet still crosses line of sight twice & at 25 yards it should still hit over an inch low, depending on the height of your mounts. Multiply by 4 to get 100 yards & you are way the hell high at 100 yards, if you crank the scope up to zero at 25 yards. Using calculators to zero, instead of shooting at the desired zero range is nearly certain disaster. Glad you finally got it worked out!
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| I think the issue is the height of the scope above the bore. If you bore-sight with a laser at 25 yards, the calculator will be accurate. However, if the scope is an inch or two above the bore, then you're creating a steeper angle at 25 yards, which is magnified at 100 yards. |
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Quoted:
I think the issue is the height of the scope above the bore. If you bore-sight with a laser at 25 yards, the calculator will be accurate. However, if the scope is an inch or two above the bore, then you're creating a steeper angle at 25 yards, which is magnified at 100 yards. Most of the calculators compensate for that. |
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Quoted:
I think the issue is the height of the scope above the bore. If you bore-sight with a laser at 25 yards, the calculator will be accurate. However, if the scope is an inch or two above the bore, then you're creating a steeper angle at 25 yards, which is magnified at 100 yards. The issue is the scope height and the calculator should have compensated for that. for my hunting rifle the scope height above the bore is 1.6 inches center to center. I put that into the calculator and the results are listed above. |
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Quoted:
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I think the issue is the height of the scope above the bore. If you bore-sight with a laser at 25 yards, the calculator will be accurate. However, if the scope is an inch or two above the bore, then you're creating a steeper angle at 25 yards, which is magnified at 100 yards. The issue is the scope height and the calculator should have compensated for that. for my hunting rifle the scope height above the bore is 1.6 inches center to center. I put that into the calculator and the results are listed above. Are your SURE? Sounds kind of low to me... |
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Back in the day we used to use the 25 yard zero because we lacked the area to do any different. We had the same results. Luckily we got some land and can sight in at 100 yards now. It's been a long time but I would like to say my .280 was 4-5 inches high at 100 when we used the 25 yard method.
Basically, there is no replacing actually shooting at distance. |
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Quoted:
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I think the issue is the height of the scope above the bore. If you bore-sight with a laser at 25 yards, the calculator will be accurate. However, if the scope is an inch or two above the bore, then you're creating a steeper angle at 25 yards, which is magnified at 100 yards. The issue is the scope height and the calculator should have compensated for that. for my hunting rifle the scope height above the bore is 1.6 inches center to center. I put that into the calculator and the results are listed above. Are your SURE? Sounds kind of low to me... yes it is 1.6 inches center of the bore to center of the scope. |