daworz
Eight Pointer
Posts: 134
|
Post by daworz on Sept 15, 2008 15:20:49 GMT -5
What do you guys do as far as sighting your Scopes? I was thinking of dead on at 100yards, most of my shots will be 150 or less. I had a Bushnell die on me and sent it back to Bushnell, but wount be returned for 2 to 3 months? So i went out and bought a new Leupold VX I 3X9X40, (I know Tar i wanted a Zeiss),and its another 200 dollar scope but had to buy what i could afford. Got a good deal mounted and bore sighted for $180, could'nt pass it up, and it was brand new out of the Box. And he told me if this one dies, that he would replace it right now, No qustion asked.  |
|
|
|
Post by RAF on Sept 15, 2008 15:45:46 GMT -5
I still do it the old fashioned way. I laser bore sight then put a target out at 100 yds. I shoot a 3 shot group and then adjust the scope to get the zero in the bull. Others use another method which haven't tried but will next time. After bore sighting set a target out at 100. You'll need some help with this or a rifle vise. Shoot one shot. With you're cross hair on the aiming point on the target adjust your scope until the cross hair moves to the point of impact. This is the tricky part 'cause you can't move the rifle during the adjustment. It helps to have someone help you with adjustments while you're hold the rifle steady. If you have a gun vise that would help. Your point of impact should now be the same as your point of aim.
|
|
|
|
Post by DBinNY on Sept 15, 2008 20:16:28 GMT -5
If you sight your rifle in 2" high at 100 yards you will get a longer maximum point blank range (MPR) (i.e., the distance at which the bullet goes no more than +/- 2" from the point of aim for a MPR of 4") than you would with a 100 yard zero. Download the free PointBlank software in tips and hints (link below), play with it for different sight in distances and you'll see what I mean. For shots up to 150 and no longer I might sight in 1" high at 100. It depends on muzzle velocity and the ballistic coefficient of your bullet. Think about it. A 2 inch correction at 100 yards gives you 4 inches at 200. With the low BC bullets we shoot at relatively slow velocities it's a good trade off if you may be faced with a longer shot. www.huntingnut.com/index.php?name=News&file=article&sid=3 |
|
|
|
Post by tar12 on Sept 15, 2008 20:17:12 GMT -5
I will not disown you buddy! ;D This weekend is looking good if you want to hook up.....
|
|
|
|
Post by mike3132 on Sept 15, 2008 20:42:49 GMT -5
Mine are sighted in 1 - 1 1/2" high @100 yards. When I sight a new scope in I bore sight it and then shoot at 25 yards and adjust to dead center, then move to 100 yards, then adjust to my final POI. Most likely you wont have to worry about sending that Leupold back in. Good luck, Mike
|
|
|
|
Post by ozark on Sept 15, 2008 20:53:55 GMT -5
After some serious thoughts about sighting in a scope I felt that I needed to create a standard or basis for doing so. First and foremost it is impossible to get the scope sighted in well on a rifle that doesn't group well. The best you can possibly do is set the scope to be centered in the group. So I am going to suggest that the first step is to fire three or five well aimed shots at a specific small target at 100 yards. Determine the center of that group and then set the rifle in a fixture or on sand bags so that it is aimed at the small target. Hold the rifle stable or have someone else hold it stable and move the crosshairs to coincide witht he extablished center of the group. This method takes into account the dispersion (Spread of the group) and sets the scope so that regardless of group size the crosshairs will be as near perfect as the rifle shoots. Chasing single bullets with the scope is simply not wise and may result in zeroing the scope to match the wildest shot of a specific group. I need some thinkers to analize this and If I am correct we can all learn a little. I don;t recall this method ever being mentioned. What you all think? Ozark
|
|
|
|
Post by lwh723 on Sept 15, 2008 21:29:01 GMT -5
Others use another method which haven't tried but will next time. After bore sighting set a target out at 100. You'll need some help with this or a rifle vise. Shoot one shot. With you're cross hair on the aiming point on the target adjust your scope until the cross hair moves to the point of impact. This is the tricky part 'cause you can't move the rifle during the adjustment. It helps to have someone help you with adjustments while you're hold the rifle steady. If you have a gun vise that would help. Your point of impact should now be the same as your point of aim. I've tried this method twice--once w/my slug gun and once w/my 10ML. It works FANTASTIC. I was high 1.5' and right about a 1' at 25 yards with my slug gun on the first shot. Next shot, after using the above adjustment method cut the 1" bull. I've never adjusted that much accurately on one try. |
|
|
|
Post by 221fireball on Sept 15, 2008 22:28:40 GMT -5
ozark i agree with your method thats the way i have always done it . That two shot is OK for getting on paper and may be all you need, and it may be the wild flyer but the more you shoot, you get more familure with the gun if new and it may show a fault in mounting of the new scope that needs fixed before you go hunting. Dead on at 100 is fine or 1" high but i would shoot at 50 and 150 . The main thing is to shoot enough to build confidence in the equipment.
|
|
|
|
Post by Rifleman on Sept 16, 2008 4:36:10 GMT -5
Raf that is a good way to do it, and Ozarks twist of making an adjustment off the group center is a great point as well. One thing that I would like to add is another step. After making the adjustment to bring the group center, or an inch high, or where ever you want zero to be, fire another group on a clean target. Then divide the group with horizonal and vertical lines through the center of the bull, or an inch high , 2 inch high, whatever your desired "center of desired impact is". Once you have done this count the number of shots that are high, and writethat number at the top of the target, then count the number of shots that are low. Repeat for left and right as well. Then count the shots in each quadrant and right that in each corner. Now you will see where you are actually hitting on average. With centerfire hunting rifles 10 shots will be sufficent to show you where your actual zero on average is. With iron sighted centerfires I like to shoot 20. With the Savage it might be best to shoot 4 or 5 separate targets with 5 shot groups each over a number of range sessions and keep them in a file until all your date is compiled and then do a final analysis. Over the years I have helped alot of shooters set up iron sighted AR-15s.M1a'a. HK's etc. After getting them centered on paper at 200 yds, and they have shot several groups to verify this, my last step has been to have them shoot 20 shots in one string of fire on a clean target at 200 yds. This is slow aimed precision fire with alot of shooter effort. I encourage them to bring their head up and rest their eyes every few shots, but otherwise stay in position. Afterwards we take the target down, divide the target and make a shot count and analysis. Quite often the shooter is suprised to find that their zero could stand a tweak of 1/2 moa in one direction or the other. Now I Know that alot of things can affect POI besides just the zero . Light, wind, shooter position, eye relief etc etc ad nausuem. However I think one can get the general idea here. Highpower shooters keep a data book, which allows them to pick up trends so they can tweak zeros as well as learn how different factors affect zero so they can make adjustments prior to the first shot. But shooting the large group on one target, or several groups on different targets and analyzing them all can be a quick and diry alternative to the data book that seems to work fine for most shooters.
|
|
|
|
Post by Rifleman on Sept 16, 2008 5:14:51 GMT -5
Here is an example I drew up real quick. Allthough not an actual target I think this might help to illustrate the pont. Here in the first picture we see what might be considered a decent group depending on the distance and rifle/optics being used. It also appears that our shooter has a good zero and no other adjustments would be beneficial.  Now after we dissect and analyze the target we start to see a trend that a newer shooter might not pick up on.  From the target analysis we see this shooter could benefit from making a small tweak to his zero as on average he is hitting high and left. How much of a tweak would depend on distance and how fine his sights/scope will allow him to make. Allthough this is just something I drew up and not 100 percent realistic, I think it is realistic enough to illustrate the concept. Most of the time when a shooter thinks he has a good zero and we do this test for real, you will find a trend that is greater then the one illustrated here. Another benefit to doing this is that the experience gained will have you looking at targets differently and you will start to see these trends sooner allowing you to make better sight adjustments as you continue to shoot other rifles in the future. |
|
|
|
Post by RAF on Sept 16, 2008 10:25:53 GMT -5
I've been giving this some thought. Seems that most like to set up their scope to hit 1 - 2 " high at 100 yds. The method I described would still work. When adjusting the scope just move the cross hairs to a point 1 - 2 " directly below the point of impact and you should be 1 - 2 " high at 100yds. The only thing I would add is when making that shot it has to be a good one and once you have done it I'd fire a 3 shot group to confirm it.
|
|
|
|
Post by esmd on Sept 16, 2008 10:27:36 GMT -5
Mine is 1-1/2 to 2" high at 100, which leaves my Barnes Originals 4" low at 200 yards.
|
|
|
|
Post by PPosey on Sept 16, 2008 10:41:04 GMT -5
All my centerfires and MLs are set 1inch high at 100,,, most shots I take are within 100 yards many under 50.
I also shoot a series of first shots to determin if the scope is truly set where I need it, with a cold gun and a fouled bore I shoot a shot, then I wait an hour or longer and shoot another at the same target, sometimes it takes me 5 days to shoot a five shot group, that first shot is all I'm really woried about.
|
|
|
|
Post by edge on Sept 16, 2008 12:11:35 GMT -5
I do like these ideas and added the thread to the Tips section.
Personally I prefer my zero to be past the longest range that I will consider shooting an animal without a rangefinder, or past my longest available shot whichever is shorter!
edge.
|
|
|
|
Post by ozark on Sept 16, 2008 15:10:35 GMT -5
I personally want to know the two points where the bullet and cross hairs meet. One will hopefully be around 50 yards and the second out at say 150. This will put me a tad high at 100 with the most popular deer rifles. 30=06, .308, .270, .243 and rifles with simular trajectories zeroing in one to two inches high at 100 yards will keep the bullet in the kill zone for a large space of distances. With a 30.30, 44 Mag and revolvers it is a different bag of worms. Regardless of where you zero to hit at 100 yards it is a benefit to have a firm knowledge of where it is going to hit at 50, 150, 200 and on out to a point where you have to aim above hair to have a chance of a good hit. As a deer passes through my area of coverage I constantly evalulate the situation for the best possible shot or to let it pass. There are so many factors besides distance to consider. The position of the deer, movement of the deer, visability, vegitation, distance being lenghtend or shortened. For the last twenty years I have been able to rely on my instincts when to take the shot. If I have a fear of failing I don't shoot because there has to be a reason to fear failing. If I am confident I will shoot in a heartbeat simply because there has to be a reason for confidence. Many will believe that I am boasting but when I shoot a deer I can tell you where I placed the bullet before going to the animal. My only aiming point on a deer is that point directly between me and the deers heart. I can get the bullet to the heart from many different positions the deer is in. I don't take shots when the deer is showing only its rear end. Ozark.
|
|
|
|
Post by Flatland Hunter on Sept 16, 2008 15:18:34 GMT -5
I set mine up for a 6" inch kill zone for max point blank range, ie... my MLII last year was 3" high at 100 that made me 3" low at 200... thus hold on center mass out to 200 yds... no holdover etc.
|
|
|
|
Post by RAF on Sept 16, 2008 15:54:20 GMT -5
I never did like holding over an animal. At long range it hard to judge a couple of inches. Used to do it when I was younger and dumber  and am sure I shot right over a lot of deer. Now if the deer is outside my comfort zone it walks. If in the zone I aim where I'd like the bullet and will hit just above or below which ='s a dead deer. |
|
|
|
Post by rossman40 on Sept 17, 2008 1:33:04 GMT -5
Rifleman, What your trying to explain is Mean Point of Impact (MPI). If you draw a vertical line thru the group with 10 rounds left and 10 rounds right, then draw a horizontal line with 10 rounds above and 10 rounds below you would basically show the MPI where the two lines intersect. You could be more precise and measure the deviation of each round and then average it to show your MPI.
In the field artillery we could do a MPI registration with a number of rounds (3-10) fired from one gun at an aimpoint and then two observers would triangulate (or one if equipped with a laser rangefinder) on each round and FDC would calculate the deviation to determine the MPI and then apply the correction.
|
|
|
|
Post by tar12 on Sept 17, 2008 4:34:08 GMT -5
3.5 inches high at 100 yds with the BO and 60 grn of N120 is dead on at 200 yds.
|
|
|
|
Post by edge on Sept 17, 2008 8:04:37 GMT -5
SNIP ... thus hold on center mass out to 200 yds... no holdover etc. This brings up a good point. Where you aim on the deer will greatly impact on your Zero range. Since I aim for the heart at all ranges shorter than my zero I have a fairly high mid-range trajectory. ! I am about 3 1/2 high at 100 and 4 1/4 high at 175 At my mid range I come close to the high shoulder shot. Once I hit my zero range I move to the high shoulder aiming point. Obviously My main aiming point could not be the high shoulder since at mid range I would risk shooting over the animals back! edge. |
|
|
|
Post by Rifleman on Sept 17, 2008 9:50:29 GMT -5
Rossman you are such a sharp guy, thanks for the insight.
|
|
|
|
Post by ozark on Sept 17, 2008 12:29:49 GMT -5
edge, your post says you are about 3 1/2 inches high at 100 yards and 4 1/4 inches high at 175 yards. Is this a typo? If not, where does your bullet begin to drop? I must be missing something here. Ben
|
|
|
|
Post by edge on Sept 17, 2008 12:33:16 GMT -5
edge, your post says you are about 3 1/2 inches high at 100 yards and 4 1/4 inches high at 175 yards. Is this a typo? If not, where does your bullet begin to drop? I must be missing something here. Ben Zero is right at 300 yards. edge. |
|
|
|
Post by ozark on Sept 17, 2008 13:05:25 GMT -5
Oh, I see the light. As long as the shooter knows where the bullet will be at a given point I see no problem. I know you do know. Ben
|
|
|
|
Post by Flatland Hunter on Sept 17, 2008 14:21:50 GMT -5
Ross, R-Man that is sharp! Took an image of R-man's example and did what Ross said and it definitely makes sense! You end up finding the approximate MPI.
|
|
|
|
Post by ozark on Sept 17, 2008 14:41:44 GMT -5
By finding the MPI and then moving the crosshairs of the scope to that point I would say that the rifle with that particular load is as near perfectly zeroed as possible. Any shots that are called bad should not be inserted in the group. Ben
|
|
|
|
Post by lwh723 on Sept 17, 2008 15:04:23 GMT -5
Ross, R-Man that is sharp! Took an image of R-man's example and did what Ross said and it definitely makes sense! You end up finding the approximate MPI. I put together a little Excel file for calculating the center of a group using the "sum of squares" method. If anyone is interested, shoot me a PM, and I'll e-mail it to you. LWH |
|
|
|
Post by lwh723 on Sept 18, 2008 14:56:04 GMT -5
I put together a little Excel file for calculating the center of a group using the "sum of squares" method. If anyone is interested, shoot me a PM, and I'll e-mail it to you. LWH Did a little more tinkering from last night. Decided could just use a straight average for calculating the center of the group. Also set it up to calculate the group size. Added another tab to estimate bullet drop. |
|
|
|
Post by Rifleman on Sept 18, 2008 15:58:20 GMT -5
Sounds cool lwh723 I am sending you a Pm. Thanks for the work.
|
|
|
|
Post by thelefthand on Sept 18, 2008 21:21:13 GMT -5
I do something similar to what Rifleman and Rossman suggest, but I put a slight twist on it. First of all, I don't bore sight. Its a waste of my time. I fire one shot at 50 yards. It's ALWAYS on paper. I make what ever correction(s) that I need to based on the 1/4 MOA, and then fire a second shot at 50 yards to confirm that I'm close to where I need to be. If I have a second person who can help me, then I make my adjustments as Ozark mentioned, but normally I'm on my own. Then I'll go to 100 and fire a group. If the group is relatively close to the center of the target, then I'll go home for the day. Otherwise, I'll make another adjustment that should be just a little shy (1~2 inches) of putting me in the center. I fire one more shot to settle the scope in, and then go home. Next I take two large pieces of paper or cardboard, and put a target in the middle of each of them. I lable one of them "1st shot", and the other "2nd Shot" Then I stop by the range some other day, set up my rest, put both targets up at 100 yards, and fire one shot at each target. Obviously I try to shoot at the target labled "1st Shot" first. Then I take the targets down, and lable both bullet holes with a "1", and at the top of the target or in my log book, I write down the date and conditions (Temp, wind, and stuff) for shot "1". Then I go home agian. Depending on the range this can take as little as 20 min. I make several trips to the range and only shoot 2 shots per trip. I don't wait much between trips. I try to take my chronograph and set it up so that I can record my speeds as well, but most of the time I just don't bother with it. The chronograph is for load development which should already be done by this point. I always fire the two shots at the same two targets. The goal is to get a group that represents where you can actually expect to put a bullet at on any given day out of your cold barrel. Every time I put another hole in the target, I label it with a new number and record the date and conditions. After several trips to the range, I have established where the first shot out of a cold barrel will hit. This represents a normal hunting situation. I also know where a follow up shot will hit. I then make the needed adjustments to the scope so that the center of my group is about 1.5" to 2" high at 100 yds, which makes it all good out to 200 yds. Then I start the process over to confirm my zero. Yes, it's a long and drawn out procedure, but it works every time for me. Too man times I "zeroed" my rifle at the range, and then when deer season comes I'm hitting left, or right or what ever. I still kill my deer, but I'm dissapointed that the bullet didn't hit exactly where I expected it to. This way I know where I can expect it to hit every time.
Another reason that drives this for me is that I've noticed that my first shot loaded into and fired from a completely cold barrel (and I mean 40 deg down to 20 deg cold, not just cool to the touch), shoots faster and hits higher than any other shot I will fire from the barrel no matter how long I wait between shots. I've waited 30 min to an hour on 32 degree days, and it still doesn't duplicate my first shot. Don't know why. It's just the way my gun has always been in the past. Maybe it will be different now with a new stock, but I'm not putting any money on it.
Well that's how I do it anyway.
Mark
|
|
and am sure I shot right over a lot of deer. Now if the deer is outside my comfort zone it walks. If in the zone I aim where I'd like the bullet and will hit just above or below which ='s a dead deer.