After returning from safari (a month ago) I got to re-check my guns at the range today. Both were adjusted to a 25-yard "zero" at the bench set-up behind the safari lodge prior to first day's hunting. The set-up included a sawdust-filled bag about the size of a 50# corn sack, atop a nice bench / benchrest affair they are used to using. The "hold" was across the length of said bag, holding the barrel and fore-end down while pulling stock tight to shoulder.

I remember us "having" to move the scopes quite a bit left and up to center the bull at 25 yards. Missed badly off sticks fhe first few days (until I compensated somehow). Anyhow, I just finished moving both scopes back to their original settings to get them re-zeroed at the range off standard rest(s). The scopes hadn't been affected by travel!!

The learning experience to share is this :

Know where your selected load(s) hits at 25 yards (so you can dispute or adjust according to what your PH prefers). You can do all sorts of load work-ups and know where you'll hit all the way up to 300 yards. But, if your PH uses a different range than 100 yards to see if travelling has moved the cross-hairs, you may have meaningless data to go by for shots at anything beside.

Maybe next time I could carry one of those 'owl ear' bags along that have plastic pellets (vs. sand) I saw Carter's Country carries for 'resting' shots taken from deer stand windows. Caldwell product?? At least I could check zero with something beside a mielie bag.

Burned by not quite enough data...

BNagel

Why did you zero at 25 yards? The only way I would ever do this is if someone told me I had to brain something like hippo in the water.

Last month we zeroed our guns at 100 yards and then I shot both my .338 and .416 at 200 to make sure they were dead on.

I insist on checking at 200 before I hunt.

...if anybody requested to zero my scope on 25 yards I would simply take it off and go with ironsights...

Mr. Zoney,

The theory is the bullet from a scope-sighted rifle will first cross the line of sight somewhere around 25 yards. The trajectory will then continue to rise to its mid-range, and then drop to again cross the line of sight at the range for which the rifle is sighted in.

The practice is the bullet might cross the line of sight somewhere around 25 yards, but probably not exactly. Hunting magazines used to publish tables for various cartridges (and MVs) so you could check your rifle at maybe 23 yards or 30 yards or whatever (depending on how flat the trajectory is). You need to shoot your rifle with your hunting load to get the exact trajectory.

I would not change the scope adjustments from any test that was not at 100 yards (or further out). I mean there are endless termite mounds in the bush, and it is quick and easy to arrange yourself 100 yards from one and check sights.

jim

ps. We San Diegans call our Arizona friends "zonies", but we do like them to come over and spend $!

Hunter:

I am well aware of the theory. I write a lot about ballistics myself. I just never trust a 25 yard zero, apparently for the same reason you don't. Here in the wide open spaces of AZ, where you can still shoot on Federal land 30 min from downtown Phoenix (wink), one never has to shoot so close.

PS - I try and stay out of California

I remember when I was a kid we always sighted in at 25 yards.

I was told that it would be a little high at 100 and right on at 250 yards.

I was 12 - how was I to know how stupid this was?

Real stupid - I hunted with a 30-30 - a mortar at 250 yards.

And yes, I went through alot of ammo and got few deer.

Is it just 1960s thinking - or getting a 100 yard sight in range is impossible where they hunt?

Back when I shot at Bisley, they had, as I recollect a 1000 inch range and target so that you could make sure your 303 was sighted in. However, we were shooting at a lot more than 100 yards. I thnk we started at 300 yards and then moved up to 500, 600, and 800 yards. I was under then impression that it was more to get on the "paper" without wasting a lot of ammo. You could then use the sighters to fine tune into the bull, or, in may case into an "outer"!
Peter.

I believe the intent was to just check sights to be on paper...But I would of definately shot at 100yds also for a dead on at 100yds...
I have seen some rifles that were completely off the paper at 25 yds...major problems...


Mike

25 yards for a scope and 12 yards for iron sights is suggested to get you on paper at 100..I can do that bore sighting...

A rifle should be sighed in at 100 yards..It should be sighted in to hit 1.2 to 3 inches high..I like 2" at 100, most shots a big game are high misses....then you test fire groups at 200 and 300, even 400 and write down its trajectory or memourize it....

Now is sighted, so check the locations of the cross hairs on your bore sighting grid and mark it or write it down...Check the bore sight grid every morning prior to your hunt..

Now your ready to hunt without mishap...To do otherwise will sooner or later cost you a fine game animal...

I've never done my own bore sighting. Any suggestions as to models I could take with me? Sorry if this is a dumb question, but I'm relatively new at this game.

Tony

Get the Bushnell or Leupold models. Don't get the laser ones. Junk.

what Ray said.. 25 yards is to get you "on".. and should be the same crossing point for 100 yards (line of sight)..

however, if you have a scoped rifle, and you want it X high at 100.. fine.. setup and get your gun there..

then adjust windage at 200, and come back to 100 and 25... your groups should be significantly smaller (spread)

jeffe

On a couple of trips to Africa, the PH's had targets set up at 25 yards. That's the longest they ever set up for. In the Free State where shooting was usually over 200 yds, the target was still set up at 25 yds. These guys were to a man convinced that if you were on at 25, you'd be on at 100. One of them even showed me the book where he learned this.

quote:

Originally posted by JD:
One of them even showed me the book where he learned this.

L. Ron Hubbard writes books. That doesn't necessarily mean the info within is true or accurate. Just my $.02.
Dave

Another AZ writer:

I had the same thought in my mind and I shot (and killed) a buff within less than 35 yards. I always thought that sighting in at 25 yards was for the purpose of "getting on paper" with new sights. I never realized that it was for keeps!

Guys

Once again, the point made is to know where your selected round(s) actually hit at 25 yards. Pick whatever you want as the 'zero', be it 50 yards or out to 250, 300, whatever.

Not knowing caused me grief.

BNagel

I suppose one uses whatever system works for him.

I have always sighted my rifles to be about 1.5-2.0 high at 100 yards. This seems to suit me fine, as I have brained buffalo at close range with it and have killed impalas at over 400 yards, and an eland at over 500 yards.

This year I missed a zebra, kongoni and a waterbuck. All of them were easy shots. My PH suggested I might wish to check my rifle's zero. I told him I thought there was nothing wrong with my rifle. My bullets were being deflected by twigs. If we see something in the open, and I miss it, I will check the zero.

The reason I did this was that my scope was set years ago, and I have never had to re-adjust it. Despite having been on several safaris.

Sure enough, next target was a buffalo at a measured 280 yards. Shot twice, and both bullets landed where I wanted them to.

I think the most important thing to remember is to judge distances properly.

This year, Walter missed a warthog standing broadside at about 180 yards. He shot right over it, despite me telling him not to aim high. He though the pig was much further than he actually was.

Next he shot a kongoni at about the same distance, and he killed it with one shot through the heart.

The 25 yard zero was intended to put you on paper, but was also suposed to be pretty close to final adjustment. I remember when I was a kid, this was Jack O'Conners recommended method.

The problem, which no one has mentioned here, is that it is dependent on scope mounting. That's the reason for the different height mentioned above for iron sights. This rule, when written, almost always included the qualifier "based on a scope height of 1.5" above line of bore". With older scopes and mounts, this was reasonable. With most modern large objective variables, its not even close. If you work out the math, 1/4" difference over 25 yds works out to quite a difference in angle. You are basically talking about a triangle 25 yds long on its base and 1-1/2" high. If you change the height to 2", you have changed the launch angle by 33%. Think what that does to your 200 yd impact point.

This system used to work for me when I was a kid. I always checked at longer range. However, I once bought a 220 Swift and mounted a Unertl 2" Ultravarmint and used the technique. That scope was probably 2-1/2" above line of bore. I was a over a foor off at 200 yds.

That caused me to think about this, and realise the true rule should be that you should adjust the 25 yd aim point downward by the difference between your scope height above bore and 1.5". This is not an easy thing to measure accurately, by the way.

Also, keep in mind that the same qualifier also applies to ballistic tables. If you sight in 2" high at 100 yds per your ballistic table, and your scope is 2" above the bore, you will be significantly higher at 200 and 300 yds than predicted. It won't be simply the half inch difference. Raising the scope above the bore is not the same as simply raising the 100 yd impact up and down, since your launch angle is changing to get the same POI.

almostacowboy: I didn't say I agreed with him. I didn't. I tried to explain the facts to him, but he could not comprehend. My wife had been hunting with him for a few days, and her scope was way off, but it was on at 25. She had missed several shots at animals in the last few days. She had another scope pre-sighted in, but never thought to put it on. When I got there, I changed out scopes for her. The next couple of days she took a Springbok and Blesbok, both over 200 yds.

JD-
I didn't mean to imply you did.
But everytime I hear something like that I remember an old Bob Sagget routine: "I read that you could nurse from dolphins. I wrote it down, then I read it".
Dave

I use the 25 yrd sighter as follows. First to get on the paper. I then sight my rifle at 2 inches high at 100 yrds. Then I return to the 25yrds target and note the point of impact. By knowing the point of impact at 25 yrds it makes it easier to quickly check a rifle. I never set windage at 25 yrds, only at 100 yrds. The 25 yrds target is only good to get on the paper and as a quick check.