Reloading q

[Reidus]

a lucky 3shot group is not that uncommon

One 3 shot group doesnt tell you a whole lot.

[Crunchy]

Either the scope is loose or you need to start over.  If those targets are at 100 yards you got work to do. 

I'd load 3  each

.010
.020
.030

And drop your charge a grain or two.

[bobcat]

Try another scope.

[Buckblaster]

I assume that you sort your brass and use all the same brand?  Mixing different brass will make a difference in your groups, mainly because the capacities vary slightly producing inconsistent velocities.

[DRobnsn]

Weather conditions?

No wind, but the temps were about 45-50f.  I think the temps were around 60-65f when I shot that good group, and no wind.

Any chance you were shooting through a chrony both times? Did you leave the ammo in the sun one time and not the next?

[wooltie]

I assume that you sort your brass and use all the same brand?  Mixing different brass will make a difference in your groups, mainly because the capacities vary slightly producing inconsistent velocities.

Yes, this was new brass, same manufacturer.

[Yondering]

a lucky 3shot group is not that uncommon

One 3 shot group doesnt tell you a whole lot.

Exactly. Trying to work up a load with only 3 shot groups can easily end up in this situation. The target pictures above are a classic example why.

If the scope or rings aren't loose, I think it's pretty safe to say you didn't work up a good load, you just got lucky with two shots touching each other. The third shot that far out should have been a clue that there's a bunch of variation in that load's accuracy.

[JLS]

a lucky 3shot group is not that uncommon

One 3 shot group doesnt tell you a whole lot.

This.  I don't consider a load reliable until I can replicate the accuracy I want with at least 10 rounds.

[Bill W]

I had a rifle named "Christine" that ran three shots thru the same hole once.  It never did that again.  I bought it from a guy who sold it for less than he bought it for and when I sold it I sold it for less than I bought it for.   Not all rifles are capable of pinpoint accuracy.  3 shot groups are usually smaller than 5 shot groups. 5 shot groups are usually smaller than 10 shot groups.  A mathematician told me once that a 26 shot group was the minimum to show how accurate a rifle was (or wasn't).

[JimmyHoffa]

On the colder day were you wearing a different type of jacket and have to pull the rifle in harder to get the same alignment?

[dune]

If the gun is wood your barrel is swelling and should be floated check with a dollar bill