Author Topic: Zeroing (Read 1034 times)

wormbobskey · « **on:** August 10, 2003, 08:16:10 AM »

I just brought home one of those heavy barrel .17 caliber rimfire bolt actions. I put a 4X32 scope on it, but I'm not sure what to zero it at. I want the rifle to be dead on at 100 yards so how high should I put impact at 25 yards when I sight it in? Thanks for any help, Worm.

jhm · « **Reply #1 on:** August 10, 2003, 09:55:02 AM »

wormbobskey: I cant speak for the 17 rimfire, but the rull of thumb for most calibers is the line of sight is crossed at 25 yards and at 100 yards that should get you close but you will have to fire the rifle at both ranges to be sure.

JIM

KN · « **Reply #2 on:** August 10, 2003, 10:59:32 AM »

You zero at 25 will depend alot on the hight of you scope. If I remember right, and I am going from memory, it will be about 1/4" low at 50yds, 1/4" high at 75yds, and zero at 100yds. 25yds will be a little lower than that. That is according to the ballistics program I use. And it was pretty close to what I get with mine. KN

Graybeard · « **Reply #3 on:** August 10, 2003, 12:01:18 PM »

If you want it to be ON at 100 yards then sight it in at 100 yards. Any thing else is pure guesswork and you might as well be tossing rocks. There is no rule that is right as to where it needs to be at 25 yards to be on at 100 yards. The old saw about crossing line of sight at both 25 and 100 yards is just that an old wive's tale. I've never yet owned a gun (rifle or handgun) that did that. Close maybe but no cigar.

There is no substitute for sighting in at the distance you want the rifle zero'ed at.

GB

wormbobskey · « **Reply #4 on:** August 10, 2003, 04:45:16 PM »

Thanks for the replies. The reason I want to know what to sight the rifle in for a 100 yard zero is that the only good shooting range I have access to is a 25 yard long pistol range. Its cut into the side of a hill with the bench between it and a mobile home. I don't want to be flinging bullets where I will be hunting. I read an article that said the bullet will drop 3 inches at 100 yards compared to a 10 inch drop by the .22 magnum. I have the rifle shooting .500 groups at 25 yards, 2 inches high. I will most likely end up going to my hunting area and putting up a target and see what I get. I have another question. Has anyone every used the duplex cross hairs as a hold on. I mean the fatter part of the cross hairs to use at maybe 100 or 150 yards, almost like a mil dot scope? Thanks again for the information, Worm.

Graybeard · « **Reply #5 on:** August 10, 2003, 06:38:34 PM »

I can "almost" promise you that if you are 2" high at 25 yards you will not even hit the paper at 100 yards unless you use a larger than 8.5"x11" sheet which is what I use.

With most of my centerfire guns I aim for about 1/2" to 3/4" low at 25 yards to assure I am on the paper at 100 yards. Where on paper is anyone's guess. You absolutely cannot sight in for 100 yards at 25 yards. All you can do is HOPE you wil be on paper at 100 yards and then adjust from there.

I do sympathize with you if you don't have a place to shoot at 100 yards except when hunting but if that's the case you're gonna hafta sight in at the hunting spot. I have a 100 yard range in my back yard. Could back off down the driveway to get as much as 300 yards I guess but my neighbords might not appreciate me being out in front of all the houses shooting back at my 100 yard back stop. At least from 100 yards you can make a reasonable guess at longer ranges but not from 25. I'd drop that zero down to 1/4" low if I were you and then adjust at the hunting sight when you get to where you can shoot further.

GB

Lee D. · « **Reply #6 on:** August 11, 2003, 03:37:14 AM »

Graybeard is right about really knowing where it will hit.
I know this doen't apply to most people here but I run an "open to the public sighting in weekend" for deer rifles at my club. What I have found after 10 plus years of doing this is that most casual hunters can not shoot a good group at 100 yards even off of a good rest. Also after many years of shooting and hunting I find that if I sight my deer guns in at dead on at 50 yards the difference at 100 is so little as to make no difference in the field when shooting under less than ideal conditions. For the better shooters and long range shooting you would probaly want to do it the correct way, but for the average 30 to 150 hunting situations (and I do believe that most game is shot between these distances) If you sight in at 50 yards and really know it is good it is much better than a poor sighting at 100. So I try to get my shooters to sight in at 50 and over the years I have convinced quite a few.
I sight in all my rifles scoped and iron sight at 50 then check them at 100.

KN · « **Reply #7 on:** August 11, 2003, 04:09:13 PM »

GB's right, You'll be shootin over the top set at 2" high at 25. I think youll need to be even lower than 1/4". More like 3/4". but theres no way to tell with out actually shooting at the different distances. KN

wormbobskey · « **Reply #8 on:** September 20, 2003, 06:19:49 AM »

GB, you were right. I had the rifle shooting 2 inches high at 25 yards and the bullets hit almost 10 inches high at 100 yards. I finally took the rifle to my hunting area and set up a target. Once I made a few adjustments I had the rifle shooting just under an inch group at 100 yards. The group was off to the left about an inch and a half, but this was because of wind drift. Later that day I took the rifle to the 25 yard range and was able to get the group size down to just over half an inch. I didn't make any adjustments at all to the scope and it shot a little over half an inch low for the 100 yard zero. Have yet to shoot any hogs with it yet. The alfalfa field that I hunt is over grown and it was just mowed a week and a half ago. We have gotten so much rain that everything is growing so fast its hard to spot anything in the tall weeds. Thanks for the suggestions on zeroing the rifle, I apperciate it. Worm :-)