How much does your zero vary?

[Mitch Rapp]

Here is my question, I plan to work up a general purpose load for my AR, likely with Nosler 77 grain bthp. I have a decent stock of ammo, mostly 55 grain fmjs, a mix of Federal, Mil Surp, Fiocchi and American Eagle.

I plan to zero my AR at 33 yards with the heavier bullets and shot it out to as far as I can, but was curious if anyone else has tested various ammos to see if they go to different poa/poi or if it is close enough to not matter? Looking for suggestions.

 

[uncle money bags]

That is the bullet I prefer, or sometimes 77 SMK's. Distance wise there is considerably more drop with the heavier round. My preferred load drops about 96 inches at 500 yards. Inside of 100, there isnt much difference. In fact I have found the windage to be more of a difference at that distance.

 

[Oklahomabassin]

Did you say zero it at 33 yards?

 

[uncle money bags]

Probably meant 33 meters.

 

[swampratt]

Yes he did.
I bet at an indoor range.
I have different weight bullets and powder and they can be as much as 8" off at 100 yards from load to load.
Barrel's whip and at a certain point in the whip cycle the bullet will leave the barrel.
This will be the largest cause of impact area i feel.
I would also think a shorter barrel will not be off as much as a longer barrel..Both being the same stiffness that is.

I took a guy and his son hunting last year and all their AR shooting was close range.
But at 75 yards they were not hitting a paper plate.
You really need to test at the range you expect to be shooting.

 

[Mitch Rapp]

Did you say zero it at 33 yards?

Probably meant 33 meters.

Yes he did.
I bet at an indoor range.
I have different weight bullets and powder and they can be as much as 8" off at 100 yards from load to load.
Barrel's whip and at a certain point in the whip cycle the bullet will leave the barrel.
This will be the largest cause of impact area i feel.
I would also think a shorter barrel will not be off as much as a longer barrel..Both being the same stiffness that is.

I took a guy and his son hunting last year and all their AR shooting was close range.
But at 75 yards they were not hitting a paper plate.
You really need to test at the range you expect to be shooting.

I am zeroing for a maximum point blank range. Read up on 36 yard zero and you will understand. I will be shooting at longer distances but there Is a reason for the 33 yards

 

[Mitch Rapp]

Here is a video, showing the different "zeroes" I used a ballistic app and the chrono info from my hunting load to determine the 33 yard zero. With my iron sighted AR and hunting load that keeps the bullet within 5 inches of my irons all the way to 300. Should be good for yotes and deer that way.

https://www.youtube.com/watch?v=g9oXGT55cV8

 

[Hump66]

I just zeroed my SPR with M193. When I switched to shooting Hornady 75gr BTHP it was almost exactly 1 mil low. Winchester 69gr SMKs were about .75 mil low and .25 mil left.

 

[uncle money bags]

Wait a second. If you already had all that info, what was the question again?

Any decent ballistic calculator is going to give you a pretty good approximation of the difference. I just used hornady's and it was spot on with my social/training ammo.

Maybe im just lost, but wouldnt the same calc tell you what different bullet weights and ballistic coefficients are going to do at distance?

 

[Mitch Rapp]

Wait a second. If you already had all that info, what was the question again?

Not looking for differences between loadings so much as brands maybe? In other words a lot of 55 grain fmj is loaded to basically the same spec, but does it actually shoot the same between brands? I know it can be different between guns just looking for people experiences like what the the guy who posted above you said.