Rezero with new ammo?

[ID_Matt]

2-3 shots would be pretty ideal. If you have a good tracking scope and hit paper the first shot.... measure the distance you are off from zero either with the reticle or by hand, make a full adjustment. Shoot 1 more, if it is off by a bit, adjust again. If it is close, shoot 2 more in to a group then make a final adjustment if needed.

This is all assuming you have a reasonably accurate gun and good tracking scope. You can chase your tail trying to zero a 1.5 MOA gun with an old scope.

 

[thinhorn_AK]

You’re pissing in the wind shooting three round groups and adjusting zero. Three round groups are statistically irrelevant if you want to ‘zero’ your rifle.

I've never missed an animal because I didn't shoot a ten shot group.

 

[cod007]

I’m shooting a Tikka 7mm RM, and if I could go back in time, I’d buy a couple of cases of Federal 160 grain accubonds for it and use them for everything. But with ammo the way it’s been the last couple of years I’ve picked up random boxes of this and that as I’ve found it. I have everything from 130 grain copper to 175 grain powerpoints and everything in between.
How do you handle re-zeroing and figuring new drops when switching ammo? I’d hate to use half a box every time.

So, I’m in the same boat with my ammo supply for a couple of my rifles. I do have a dope chart on my phone for my favored bullets for said rifles.
I zero at 200 yards w my rifles. I have found that re-zeroing w new ammo only takes a shot or two, maybe 3. Just have to make sure you are comfortable with your shots/shooting position etc.
The ‘rezero’ should be pretty simple and easy. What requires more shooting is when you start shooting out to 350 yards or more. My dope chart for 120 grain is not going to be the same as 143 grain when you start getting out at further distances. If you are only shooting out to 300 yards you are not going to be far off enough to affect a killing shot just because you changed ammo once you re-establish your zero, IMO.

 

[isItFallYet]

I zero my rifle with the ammo that I shoot most. When shooting different ammo, I document my dope and tape it to my stock so I can reference it easily.

 

[WCB]

You’re pissing in the wind shooting three round groups and adjusting zero. Three round groups are statistically irrelevant if you want to ‘zero’ your rifle.

are we going to get 30 pages of the cone theory. For a basic hunting "zero" 0-300 yards it will be just fine. Funny I have only ever shot 10 round groups a few time in my life with my main hunting rifles at 100 or 200 yards this was long after confirming zero with 3 or 4 shot groups. Never owned or have had any load or firearm of mine through a chrono. and the world hasn't ended yet.

 

[Laramie]

Ha, I guess 400 yards is long range in my world.

It is long range to the vast majority of shooters. I'm sure there are quite a few on this forum that consistently shoot further, but that isn't the norm. Anything past 300 takes repetition and great form to execute imo. My limit while hunting is 500 and I put in work every summer to feel comfortable keeping it there.

 

[swavescatter]

The answer is that you sell the ammo you don't want and pay the difference for the ammo you need. Sell high and buy high on auction sites if needed.

Edit - consider the cost of the ammo you need to shoot to rezero ($/round) and your time/fuel/range fees. My guess is that you'll come out ahead and have more of the ammo you want without needing to rezero.

 

[Antares]

I'm not a big proponent of small sample sizes, but you can absolutely have a good zero with three rounds if you're a decent shot and have good equipment.

Below are seven 3-round groups........using factory ammo........shot on different days.........and the suppressor was removed and reattached in between groups.....

7-15-2021 - 0.328 MOA
View attachment 343215

8-4-2021 - 0.241 MOA
View attachment 343216

8-6-2021 - 0.577 MOA
View attachment 343217

8-10-2021 - 0.312 MOA
View attachment 343218

8-10-2021 (2) - 0.416 MOA
View attachment 343219

8-12-2021 - 0.357 MOA
View attachment 343220

8-17-2021 - 0.499 MOA
View attachment 343221

Aggregate & Breakdown:
View attachment 343223

View attachment 343226

21-shot aggregate is about 3/4 MOA, and the difference in dope at 1,000 yards tells the tale. I've shot a single round after remounting that scope, adjusted, and had a good zero with that set-up on more than one occasion. Again, I'm not saying everyone can/should use 3-round groups. If you have one of these set-ups that's 1.5 - 2.0 MOA for 10-round groups, then yeah, you better use more than 3. I'm just saying it's completely doable for some.

To the OP, I think a single box is pretty worthless unless you are keeping shots pretty close. If you have unknowns (shooter, ammo, scope, rifle, etc) you will want way more than a few rounds.

What program is that? OnTarget?

 

[Wapiti1]

This isn't that complicated. Re-zero with minimal shots. Shouldn't take more than a couple with a good rest and good form. Shoot a 3-5 shot group to confirm zero, and get a feel for group size. If group size is dodgy, move to the next box of ammo. I'd be okay with 1.5" or less on a 3-5 shot group centered on the aiming point.

Shoot at longer range, like 300 to check the drop from 100 yards. Input this into the ballistics program, and true it up with velocity adjustment.

Don't shoot at animals farther than 300-400 where your margin for error (minute of deer) is acceptable. Be honest about your approach, and impose appropriate limits. This approach works, but you aren't wringing the bugs out of the system.

Jeremy