Reloading Mystery - Accurate Tumblers!

How is this possible?

Savage M12
1/9 twist
.223
55gr Varmit Nightmare X-Treme HP
24.5gr IMR 3031

Out of 65 rounds today, I had 5 tumblers.

All other shots were tight and accurate.

Four of them were tight in their groups.

I left this one alone to show how accurate it was.

What is up with this??

http://img.photobucket.com/albums/v334/doc540/Guns/Targets/349f47af-be69-42e8-bb2b-84fd128f515a_zpsd07207e9.jpg

just because it put one bullet where you were aiming doesn't mean it's accurate

reread my post

All FIVE tumblers were tight with the other shots in their groups.

oic

My guess is that it's not tumbling. The paper is tearing unevenly.

I see you are using 24.5gr IMR 3031. Do you have another powder and/or bullet to try? As far as your load weight (I don't have my book in front of me) but where does that land in between the min/max for that powder and bullet combo?

Also - any chance you are having any leading or possibly blow-by? Did you keep those cases to check for any issues? It looks like the bullet isn't getting up to the proper speed and/or it's not connecting with the rifling.

Could it be possible you got some heavier bullets mixed in with the 55's?
They obviously didn't stabilize, but a 1:9 should still stabilize a bit heavier.
Curious.
Have you double checked the twist in your barrel with a rod to see if it's actually 1:9?

I'm curious as to those bullets. I've read that they are repackaged 'major manufacturer' bullets? Do the weigh consistently? .224"?

Try shooting at paper plates or card board and see if it continues to tumble.

I don't use the Varmint Nightmare HP but do use the soft point. They shoot very good an dI've never seen one of those tumble.

Be sure to verify that your crown hasn't been damaged.

thanks, all good things to check

yes, it's shoots 77gr just fine

gunsmith report:

crown ok
barrel ok
brass ok

I've weighed the bullets: all at 55gr

BUT there could be a few "bad" bullets in the bulk pack.

I didn't get this many tumblers from the Varmit Nightmare soft points.

And I think they're made by Hornady and repackaged by Natchez.

I don't think Ive ever seen a keyhole that distinct.

Try shooting at paper plates or card board and see if it continues to tumble.
Bullet tumbling has nothing to do with the targets. How the hell would a bullet know it was heading for a paper plate? They tumble when they cannot stabilize while spinning (or if they hit something hat destabilizes them)

I don't think Ive ever seen a keyhole that distinct.
My R700 223 with a 1:12 twist will do that every time with a 75 gr Amax

He means a paper plate or a cardboard target will not tear out like thin paper and will reveal whether tear-out is occurring.

What I'm saying is that the bullets may not be tumbling. Sometimes paper tear unevenly, whereas cardboard or paper plates result in round holes. So if you use cardboard and you don't get any kekyholing, then maybe there is no tumbling.

This is just a theory. Perhaps the bullets are destabilizing just before impact. It is, however, unlikely that a bullet will be keyholing and produce 1 MOA accuracy.

It's too bad you can not recover some of the bullets (the ones keyholed).

With the powder charge you are using Hodgdon says the bullet should be at 3200-3300 fps. I think at that velocity and twist rate the bullet may be stripping the rifling in the bore and not stablizing in flight. So you have occasionally a keyholed bullet.

They are definitely tumbling.
With only one hole in the paper it's hard to say how they group.