First time firing the .260 barrel and there was a .8mil shift down (more or less what I was expecting) and a 1.2mil shift right (not what I was expecting) from the .308 barrel at a 100yd zero. Is this much horizontal shift common? Is the cause barrel run out? What are your thoughts?
- Thread starter alman1531
- Start date
I think the general consensus is as long as the POI shift is consistent, you don't have anything to worry about.
When a barrel is freshly cut and chambered to it's new receiver it's never going to be perfectly in alignment with the horizontal axis of said receiver. So what a good gunsmith will do when they cut the barrel is find it's wobble point or where it's slightly askew and index the barrel vertically so it shoots slightly off but only in the vertical axis, follow? So when your gunsmith indexed the new barrel onto the receiver he possibly got it off? Now here's the kicker…. It is perhaps that the previous barrel may have been askew or off in the horizontal axis all this time and your comparing the POI shift to something that was always off.
In either case, it's strictly academic as that amount of shift can more than be accommodated for with a couple of clicks of horizontal adjustment on the optic in MOA or Mils.
in other words… no worries dude.
It's a completely different barrel, and a completely different caliber ...
What did you think would happen, your scope would keep the zero for both?
Doesnt matter the gun or who made the barrel, the zero is not gonna be the same. Maybe we need to get a bit more realistic in your expectations ... Swap the scope from two different gun and you'll see a similar result, even if they are the same kind. Change the bullet and watch it change again.
Hate to break it to you, you'll have to rezero, change bullet weight with your 308 and you'd have to rezero forget about caliber. It's not some magic system that keeps the zero across all barrels or calibers.
Here is another clue, hang a suppressor on it and it will change again, change muzzle brakes it will also happen with that. You're taking stuff that used to cost extra time and money with a trip to the smith and doing it at home. Get over it and move on.
What did you think would happen, your scope would keep the zero for both?
Doesnt matter the gun or who made the barrel, the zero is not gonna be the same. Maybe we need to get a bit more realistic in your expectations ... Swap the scope from two different gun and you'll see a similar result, even if they are the same kind. Change the bullet and watch it change again.
Hate to break it to you, you'll have to rezero, change bullet weight with your 308 and you'd have to rezero forget about caliber. It's not some magic system that keeps the zero across all barrels or calibers.
Here is another clue, hang a suppressor on it and it will change again, change muzzle brakes it will also happen with that. You're taking stuff that used to cost extra time and money with a trip to the smith and doing it at home. Get over it and move on.
Ahhh I see, yeah so I see that those barrels are quick and no smith required on the AI. Yeah, still same thing, my assessment still holds up as a possible reason. Each barrel even on same caliber is cut (bore hole, rifling) differently so even going from 308 to another 308 would yield different results. I go from 308 to 260 to 338 on my DTA and shits all over the map. Not a problem.
I knew that the zero would not be the same. I just was not expecting the horizontal shift to be 1.2 at 100. As long as the shift is consistent then no need to worry.
I knew that the zero would not be the same. I just was not expecting the horizontal shift to be 1.2 at 100. As long as the shift is consistent then no need to worry.
Switching my DTA from 308 to 260 the shift is 1.0 mil up and 0.5 mil right, but always consistent. I keep my rifle zeroed on the 308 and just adjust the scope when I switch to 260. My S&B scopes only allow down adjustment of 0.5 mil from zero, so would have to rezero the scope each time when switching from 260 to 308. Just makes sense!
I'd be more surprised if there wasn't a shift. It's going to happen. This is why I prefer to just have another rifle. Granted, that's not economically viable for everyone, but I'm makes life much simpler.
