50/200 or 100 yard zero?

[jhs1969]

I know this has been discussed before but I can't find anything that relates to my paticular question. As I stated in another thread I recently switched from an absolute co-witness mount to a lower 1/3 mount and re-zeroed to the 50/200 that I had been using before. But I noticed that my impacts are now higher at 100 yards than before. I've noticed some of the high end-users recommend a 100 yard zero anyway. I'm considering going to the 100 zero but would like some thoughts from you guys that are using this zero in comparison to the 50/200, and does anyone have any trajectory info that show the difference between an absolute and lower 1/3 set up?

[6933]

What will the main purpose of the rifle be?

[jhs1969]

What will the main purpose of the rifle be?

It's primary use is for home/self defense but it is also used for training, and occaisionally hunting.

[shootist~]

Per JBM Ballistics the difference in impact (assuming a 200M actual zero) for a sight hight change of +0.2" (the ~diff for absolute and lower 1/3 co-witness) is only 0.1" at 100. You probably just zeroed it a little different with the new setup.

As far as 100 VS 200 Yds/Meters for a zero - IMO it makes absolutely no difference so long as you stay with one or the other.

I've zeroed everything (RD, scopes and irons) at 200M for decades so my POA at 100, 150 & 300 is somewhat ingrained. I enjoy wide open spaces to shoot in however, so what works best for you might be different.

[bkb0000]

you have a flatter trajectory for longer with a 200m zero... 100m zeros with 5.56s coming out of this platform are petty impractical. your holdover at 300m is like three times what it is with a 200m zero. with the 200m zero, your maximum hold-under is like 5" or less. so basically, you can pretty much just set your dot on target and fire, anywhere between 50-300 meters. just going from memory- i'm sure somebody will post a chart that better articulates.

[rob_s]

When you say "50/200", which is it, and how did you achieve it?

[The Solid]

It means that at 50 and 200 your trajectory are basically the same point.

[bkb0000]

It means that at 50 and 200 your trajectory are basically the same point.

m193 will be less than 1" up or down, at either, with either, IIRC.

[rob_s]

It means that at 50 and 200 your trajectory are basically the same point.

"basically"? Just how "basically"? When you zeroed at 200 and then checked it at 50, how far off were you? How different was the POI at 100 when you first got POA/POI at 50 vs. when you locked in a zero at 200? Is it even possible to get a "zero" at 50? What size groups were you getting at 200? With what optic? What ammo? What barrel?


these are all intentionally leading questions, because the internut convention of the 50/200 is a myth, and generally completely misapplied and untested by most who use it and advocate others do the same. Simply getting POA/POI at 50 and calling it a day is not adequate, however I suspect it's what the OP did, hence my questions in my first post.

[rob_s]

On the subject of the thread title...

I have moved to a 100 yard zero for my carbines. I believe that the 200 yard zero is the better rifleman's zero, and I believe it's the better all-purpose, minuteman, EOTWAKI, etc. zero. But I have still moved to a 100 yard zero.

I ultimately don't think it matters one iota which zero you choose, and I think that the far more important thing is to pick one or the other, get trigger time with it at all distances, learn the hold-overs/unders, and learn the benefits and limitations of your choice. Oh, and become a good enough shooter to understand and utilize natural point of aim, sight picture, and trigger control, to really have confidence in your shooting ability so that you're not chasing your zero all over the target.