What is a Zero offset?
For those of you who have not shot ELR, you may not be familiar with offset. For most ELR rifles, having a 100m zero may not make sense. These rifles do not see much shooting up close. In order to gain more range from their scope, ELR shooters will zero their rifles to be say 12-18″ high at 100m which would be a 600m zero or so, then take the gun out from there.
Most ELR scopes sit on an angled base such as a 30-70MOA rail plus some sort of adjustable mount such as an Eratac adjustable mount with 0-70MOA of selectable adjustment. This gives the shooter a significant amount of elevation travel. The tradeoff is that they may not be able to zero it up close.
Below Is an example from Ryan Cheney’s interview:
Ryan: I run Nightforce ATACR 7-35 mil-c scopes on everything and one of them has a mount for a Tacom HQ Charlie Tarac prism. I had it on my 33xc for the 2 mile plus shots last year at Spearpoint, but on my Cheytac with a 40 MOA action rail and a 44 MOA Spuhr mount and a 18″ offset, I only had to hold over by 4 mils on the 2 mile target at KO2M. (Editor: Gents did you know that you have a setting in your kestrel specifically to plugin this offset and it will deduct that offset from your come ups? Basically your rifle is zeroed at 1000yards or so) In the example below, I added 18″ of offset to my Kestrel so it deducted the elevation required by some 17.25MOA
Rod: Below is an example using an offset in my kestrel for the 300Norma Mag. With this offset, a 2000m shot would require 63.8 MOA instead of 79.8MOA as we have an 18″ offset at 100m. Kestrel will deduct that offset from the correction needed.
What can you use if you want to dial from up close to very far out? The March Genesis scope 6-60×56 offers up to 400 MOA of vertical travel for extreme long range shooting without any additional devices.
A March Genesis 6-60×56 is mounted on this 375 Cheytac built in Italy by Littleboy Rifles.