eldeguello

This statement is based on a knowledge of a particular cartridge & load's trajectory curve. So, as mentioned above, it is THEORETICALLY CORRECT, and in addition, it DOES NOT take into consideration deflection (AKA windage) differences.

Over the years, I have THOROUGHLY tested this idea with a number of different rifles and cartridges. My findings arethat sighting in at ranges like 25-27 yards, etc., will usually get you "on paper" at 100 yards. But if you rely on a 27-yard zero to ensure that you are "dead on" at 200 (or any other) extended range, you are in for a serious disappointment! I have found that to make sure you are hitting where you want to hit at any of the extended ranges, it is ABSOLUTELY NECESSARY to shoot at those distances to MAKESURE of where your point of impact is out there. Additionally,I have found is that it is usual for the bullets to be off in deflection (windage) more often than in elevation.

So go ahead and zero at 27 yards to begin with. Then move to 200 and fire two or threerounds to actually see for yourself what reallyhappens with that particular rifle and load at 200 yards and beyond....

kmunny19

exactly. 27 is the right number for an exact cartridge, with an exact scope height, and an exact barrel length. alter any of those and 27 may not be the number anymore. if you insist on sighting in this way, find a ballistics program and check the exact set up that will be used. this can be a good way to sight in, but you need to do your homework on the exact set up you'll use first.

Paul L Mohr

Another thing to consider is the scope adjustment itself. Most scopes are set up for 1/4 inch per click at 100 yards. Some varmint and target scopes are 1/8 of an inch per click at 100 yards (mine is). This means at 50 yards it is half that and at 25 it is half that again. Meaning that while sighting in your gun at 50 yards you will need to move it twice as many clicks as you would have at 100. And at 25 yards it would be twice that again. So for a 1/4" click scope you would need to move it 16 clicks to change your bullet impact 1 inch.

Lets say you shoot your gun at 25 yards and it is 2 inches high and 3 inches off to the left. You would need to dial in 32 clicks down and 48 clicks right. With a 1/8" MOA scope it would be twice that![] Taking into account bullet hole size and group size you could easily be off by 4 clicks and not even know it, maybe more in some cases. And that is providing your scope even has that much adjustment in it.

Now lets take this same scenario out to 200 yards. 1 click on your 1/4" MOA scope would equal a half an inch of impact shift. So if you were 2 or 3 inches high and left at 200 yards you would only need 4 or five clicks to compensate for it. Those four clicks you may have been off at 25 yards would correlate into 2 or 3 inches or more shift at 200 yards.

And this does not even take into account other factors like velocity differences, altitude differences, sight height and even shooting form.

As you can tell I am not a huge fan of close range zeroing of scopes. I mean it might get you close and would be ok for shooting large game at moderate distances if you were not overly concerned with precise bullet placement. However for any kind of accurate shooting like smaller animals, varmint hunting, more precise shots or target shooting I just don't see it working.

I like to sight in for windage at 50 yards, then check it and touch it up at 100 yards if it is a calm day. Then zero my gun for elevation at the actual distance I want it zeroed at, 100 or 200 yards. A good trick for this is to not shoot at a bullzeye, use a line on the target from left to right and and just concentrate on getting the bullets to strike or center on that line. Don't worry about the left and right movement. It makes things much easier because you are only concentrating on one axis.

My opinion anyway

Paul

Briman

From my experience, being on at 25 yards will put you very close at 100, being on at 50 will put you about 5-6minutes high at 100.

Paul L Mohr

I was talking windage (left to right) not elevation. I like to use 50 yards to start with for windage because wind doesn't effect it that close, especially with slug guns and ML's. And windage really shouldn't change much as distance increases as long as it's calm out. It may need touched up a bit though. Elevation is what changes as distance changes and needs to be varified at the distances you actually intend to shoot at.

That has always been my theory anway.

Paul

RugerM77.270

IF its true its not going to make up for shooting it at 200. If you are off by a 1/2 inch at 25 you are off by 8 inches at 200 yards and that adds up to a wounded deer. At 25 yards you may not ever see that 1/2 inch.