Reloading Mystery - Accurate Tumblers??

[doc540]

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??

[cycle61]

I can't answer the question, but that picture is great.

[the86d]

How is this possible?

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

What is up with this??

WOW!
Are you sure it is not a 0/3600 twist?

[ChrisGarrett]

Brand new Model 12 VLP 22-250, no scope, 25 yds, 80gr Final Finish SMKs through a 1:12" 26" tube.

Maybe you had some heavier/longer bullets mixed in by mistake?

Chris

[doc540]

YIKES!!

[rcschummers]

Looks like elmer fudd got ahold of your rifle.

[wood carver]

Brand new Model 12 VLP 22-250, no scope, 25 yds, 80gr Final Finish SMKs through a 1:12" 26" tube.

Maybe you had some heavier/longer bullets mixed in by mistake?

Chris

At least there's a couple of nice groupings.

[CAL.BAR]

FWIW - that was happening with my HK G36. Turned out that the barrel was worn out. Something to think about at least.

[Fjold]

If your barrel is not worn out then you are probably right on the velocity margin for stability. Standard reloading procedures will usually give you velocitiy differences of >100 fps between your fastest and slowest loads. Your slowest rounds are not being spun fast enough to stabilize the bullets. Bump your load up to the next increment (0.2 - 0.5 grains) and see if that solves your problem.

Your load is not too light and you should have more than enough velocity to stabilize those bullets, so if the barrel is not worn out, I'm a little puzzled as to why your bullets are tumbling.

Keep in mind that if they are tumbling at 100 yards you need to bump them up a lot more to keep them stabile at longer ranges.

[huckberry668]

Yes, key holes... I had my share of them. worn barrel is the biggest culprit, bad crown, ding'ed muzzle, bullet defect and your reloading method.

Your picture looks like the bullet isn't concentric. measure you bullets, run-out, ogive to base, diameter, weight. Try other bullets, heavier ones like 69gr SMK and see if it still happens. Let's hope it's the bullet and not the gun.

Share some of my experience with you..
1. I had a Colt Sporter HBar from the early 90s. After about 2,000 rounds fired I get key holes and tumblers so bad all but 3 out of 20 hit the target. and some are key holes. turned out the chrome was peeling off of the throat area and shredding the thin jackets. However it only happened with the thin jacketed 52gr HP SMKs. 69gr SMK shot fine.

2. I had a Savage 10FP in 223. The tool mark was so bad that there was no visible rifling at the muzzle for about .25". It wouldn't shoot thin jacket bullets and cause a few key holes. It was repaired and returned by Savage with an even worse crowned barrel and it too had the same key hole problems with light bullets. 69gr SMK shot under MOA tho.

3. Someone I used to know ran his loaded 45ACP rounds thru the sizing die (with the decapping pin removed). His p220 shot nothing but key holes with that ammo and of course he blamed the gun till I asked about his reloading method.

4. I experimented with 223 Lee Factory Crimp Die on SMks. Heavy enough crimp caused accuracy loss. And too heavy of crimp cause key holes and shredded bullets that never made it to the target.

5. I had a AR10 upper with pressed-in muzzle break installed slightly off center. Bullets sometimes hit the muzzle break and cause a few key holes. Same situation with some badly installed fake cans on a few AKs that came into the shop for the same reason.

[doc540]

thnx!

Narrowed it down to the bulk bullets.

They're Hornady seconds so a few are probably out of spec.

Not a big deal since I don't hunt or shoot matches with them.

Might gut shoot a paper target once in a while, but I can live with that.