The 1/3-second zero

[Runnin_Chupacabra]

I was reading an article in Game & Fish this morning talking about zeroing your rifle at the distance your ammunition travels over 1/3 of a second. Pretty interesting point he makes. Not sure if it something I would endorse at first glance but keeping an open mind. Thoughts on this gentleman's school of thought? Anyone have any experience with this?

 

[VikingsGuy]

I may be missing something, but this just seems like a small variation on calculating Max Point Blank Range - which is done by the computer these days anyway. I am a fan of MPBR if folks don't dial elevation or use BDC reticles, but since most of my scopes now have one or the other I tend to zero at 200y (or the ballistics table equivalent at 100y).

 

[SAJ-99]

Did you post on the ammo or firearms forums? Seems they would eat this up. It might be mathematic interesting as well, but I don’t have an opinion. I zero at 200 which means I’m 1” high at 100, and use the ballistics table after that.

 

[ChrisAU]

Did you post on the ammo or firearms forums? Seems they would eat this up. It might be mathematic interesting as well, but I don’t have an opinion. I zero at 200 which means I’m 1” high at 100, and use the ballistics table after that.

Mind me asking what kind of laser beam that is that you are shooting?

 

[SAJ-99]

Mind me asking what kind of laser beam that is that you are shooting?

270win, with 130grn bullet, but I think that is pretty standard method. At least people I respect told me that. The discussion on ballistics is fascinating, but I rarely if ever opine because it’s not my thing. I had to go back and check what I wrote after your post to make sure I didn’t mistype something, and I’m still not sure.

 

[cahunter805]

Most rifles are 2”-2.5” high at 100 for a 200 yard zero. I like a 250 zero.

 

[matt0550]

Most rifles are 2”-2.5” high at 100 for a 200 yard zero. I like a 250 zero.

A big portion of this will be dependent on your sight over bore measurement as well...cant leave it out of your equation. Here is an example of a .338 LM firing a 265gr Nosler at near max charge...center of sight to center of bore is just a smidge under 2.1". It is actually 1" high at 100 yards and dead on at 200. OP, the MPBR is pretty close at 1/3 second.

 

[cahunter805]

Matt
I agree with sight height being important especially at longer ranges. I was more speaking toward the normal hunting cartridges but the 338LM could be that for some.

 

[matt0550]

Matt
I agree with sight height being important especially at longer ranges. I was more speaking toward the normal hunting cartridges but the 338LM could be that for some.

I hadn't even considered that lol...I shouldve chosen a more normal caliber as example

Maybe 6.5 Creedmoor (though I have come to realize it is controversial to speak of it).

 

[SAJ-99]

Most rifles are 2”-2.5” high at 100 for a 200 yard zero. I like a 250 zero.

The box of ammo says 1.5, so I can go with 2. It doesn't matter to me because my comfort zone is under 300. The human error is a lot more than that 1" difference I misquoted.

 

[elkduds]

So the fastest hunting bullets will need more than a second to travel 800 yards. How far can an animal move in 1 second? One of a long list of reasons shots that long are unpredictable, no matter how competent the shooter.

 

[44hunter45]

Why does it seem ammo makers think deer and elk have a 5" kill zone? Must be all those 6.5 CM out there. Looking at photo on the article I thought they might have called how to blow out your hearing in 1/3 of a second.
Anyway, using his numbers, QuickTarget results give a no-math, no correction hold for a 7.4" kill zone out to 320. That is pretty real world doable to me.