Home Forums Hunting & Shooting Ask The Gunwriters 25 yard sight in ?

A guy at work bought his son a new 243 for x-mas. At lunch he was telling us that they went out and shot it,and sighted it dead on at 25 yards,and that it will be dead on at 100 yards. Most of us disagreed and told him that it will be way high. Not having the time to test out our collective theory,what say you? ---Thanks 1Longbow

He should be on the paper at 100 and that's all.

I always shoot out to 300 because some loads that drive tacks at 100 suck at 300. More frequently a slight cant in the scope mounting that won't show up at 100 will at 300 as a windage error. When you correct at 300, you'll be good.

The best reason I've ever heard of for knowing your rifle's 25 yd point of impact was that if you ever had reason to question your rifles zero, such as after a fall while carrying your gun, was that one could check it in the light cast by your vehicles head lights when you returned back to camp etc., and confirm whether or not your rifle was still zeroed or not.

As far as zeroing my guns at 25 yds and calling it good, never!

He will get that result only if he is extremely lucky.

Depending on the bullet used, the 243 has quite a range of possible muzzle velocities and ballistic coefficients, so it's pretty hard to say. And 1/4" at 25 yards translates to a big change in where you get your second crossover. Using the RSI Shooting Lab, 100 grain bullets, and 2950 FPS a 25 yard first crossover gets you about a 250 yard second crossover.

I'd just suggest to him that he test his idea before he goes hunting. Hard to argue with a group several inches from where you believe it should be.

It takes a really low-mounted scope to be even as low as 2-3" high at 100 after a 25-yard sight-in. It also works OK wioth iron sightrs.

This is why some old-time gun writers advised it, but it hasn't worked all that well in a long time. Generally, with a cartridge that gets muzzle velocities in the 3000 fps range, and a typical 3-9x40 scope, the impact will be more like 4-8" high at 100 yards, depending on the scope height over bore. That's assuming the rifle really was sighted-in precisely at 25 yards.

Which is why I normally do preliminary sighting-in at 35-50 yards anymore.

I tried the 25 yard dead on sight in and found I was 8" high at 100 yards with my 30-06 shooting 180s. A friend said he had the same results, but with a 300 wby.

25 yard zeros are the spawn of satan. The military teaches a 25 meter zero with the M16\M4, although we use a slightly less than line of sight zero. The sights on the AR platform are two inches or more above the sight plane. If the zero isn't confirmed at longer ranges it makes for some poor long range shooting. Luckily the better units are smarter than the manuels and do some things the wrong way.

Apparently they still teach the 25-yard (or actually, meters) sight-in at the South Africa professional hunter school. Or at least I have hunted with at least 2 PH's in RSA that insisted on the 25-yard/meter sight-in and that's what they told me they were taught.

One of them was quite arrogaant about it too, especially when I insisted that I shot my rifle at 100 yards too. Turned out it was 7" high. He was astonished, because he had never checked it before....

+1 on all my hi-velocity rifles, & usually closer to the 8" high than the 4".

MM

Yeah, you have to get the scope really low to get around 4". Most mounts and scopes won't get there anymore.

One shorter-range sight-in that does work fairly well is an inch high at 50. This is a LOT better than dead-on at 25, and if the scope isn't too high, or the cartridge too fast, it will work out to 200-250. But it's a lot better to shoot the dang rifle at longer ranges if that's what you might do in the field!

I once knew a Montana rancher/outfitter who insisted all his new clients sight-in at 25 when they got to the ranch. A lot of them missed, of course, especially the guys who came from further east and had "see-through" scope mounts on their deer rifles. The rancher has an old Remington 721 .270 with a K2.5 Weaver mounted really low, and it worked with his rifle, but not many others. But like a lot of people who have limited experience, he assumed it worked for all rifles, all the time....

Thanks guys for confirming what most of us thought ,I have forward this post to him. Somehow I see us at the range. he's one of those guys that has to see it to be true. Thanks again --1Longbow

Good grief.........



Casey

And then they have the nerve to make fun of the clients' shooting. I've seen it quite a few times, and more and more South Africans are going to the 25 meter zero because lots of clients take forever to get their guns on at 100.

I was just in Turkey where the guide kept trying to tell me where to zero my gun and where to hold, even though he'd never heard of the .300 WSM or TDS reticle before. Despite his ignorance, he was quite pushy until I put my foot firmly down and told him I knew where my own damn rifle shot.

Greg, I've had the same experience too many times to remember. As a result I am both getting to be something of a PITA client--and also prefering to hunt on my own, right here in Montana. (Though the last may just be a result of getting older, and less find fond of airplanes.)

I don't think this know-it-all attitude is specific to any certain culture--except that of "expert" hunting guides. Most think they know everything about shooting, even with limited experience. (Gee, something like the Internet?)

FWIW:

There is no way to know unless you shoot.

Here is a 2x2 post it note with 3 shots each at 25, 50, 75, and 100 yards.

All of these are from a 308 cal AR with a scope.

Its a 100 yard zero.



BMT

I couldn't believe it the other day during MNF when they let the cat out of the bag that Madden never flew, always took a bus. I guess that's a hard way to get to Africa, however. I suspect your reasons are different than his though. Fear vs. Frustration?

so in a pinch this year on a new 308 I estimated the velocity to be 2800FPS, measured the height of the scope off the barrel to be about 1.5 inches, determined that I needed to be about 3/4 inches low at 25 yards, dialed it in at 25 and went hunting. First shots at 100 it were a bit high, I cannot remember but not more than 3 inches. I normaly never do this but it was raining the entire week before the weekend and I wanted to hunt with this rifle as it is my "rain gun". Maybe I got lucky. I did almost lose a rubber boot in the mud that weekend!

Back in the 80's, I hunted with a guy who only sighted in at 25 yards. He hunted out of tree stands in thick woods, and never shot much farther than 25 yards.

I've been using free Pointblank software for a number of years now. One of the things I use it for is just this sort of thing. I sight in at 25 yards. However, before I do, I crank the load through Pointblank and figure out how low to the bull I should be shooting at 25 to be an inch or two high at 100 so that I'm close to dead on at 200.

One or two shots at 25 yards confirms that I'm at least going to be close at 100 yards.

Aletheuo,

The reason I'm hunting more around home anymore is more related to getting tired of airports than anything. Plus, the airlines have made it harder and harder to get the meat back. I hunted Alaska in 1996 and got both a moose and a caribou, and the airlines involved (greateful for hunting business) allowed me to bring it back as baggage, with just a small excess weight charge. These days it would cost hundreds of dollars.

So I don't go hunting much anywhere that's too far to drive, unless the hunt is really special. I went to Alaska to hunt grizzly in August, and am headed to Tanzania in June. But for the rest of it I am pretty well satisfied to hunt within a day's drive of home.

The other factor, of course, is that I've already done quite a bit of hunting in other places!