Helical residue on target holes

[tankgijohn72]

Just curious if anyone has ever seen this before, or know what it is. Doing some load development on a 26 nosler. These were 147 ELD-Ms RL33 Powder. Know what caused the helical residue on a few of these shots? I have never seen it in thousands of rounds, and no other rounds showed this phenomena. My thought was that the barrel was just completely fouled, but groups fired after this one did not shot the pattern.

 

[Bbear]

I was reading in another forum that the helical marks could be from the bullet starting to come apart.
http://www.rugerforum.com/phpBB3/viewtopic.php?f=4&t=269904

scroll down and look at the pictures.

 

[Tyler Kemp]

That's some interesting stuff! I'd tag Hornady perhaps, or with your permission I can ask them. I'm sure folks would have all sorts of ideas, maybe they've actually seen it before?

 

[RockyMtnMT]

I have seen some guys reporting that they are coming apart with high vel launches. Your Nosler certainly puts you in that kind of speed. Non bonded bullets have trouble with 3200+ fps unless the jacket is thick. Seems like most bullets now days have gotten better at handling the vel capability of the big mags. Remember Berger when they came out with the 300g .338 had to change the jacket to handle the big guns. I suspect the same here.

Steve

 

[J E Custom]

I Agree with the others, It looks like jacket separation.

Normally, this is from to much velocity or twist, Or a combination of both.

Try a longer yardage and the issue will probably become obvious.

If you can recover one of the bullets, that could also help decide.

J E CUSTOM

 

[tankgijohn72]

Probably wont be able to cover the bullets, its at a public range. its a 1-8 twist. Didn't chronograph it. Curious as to how the lead would erode yet the hole be round? Think the jacket cracked?

 

[RevJim]

Yep, bullet is leaking molten lead from cracking/splitting jackets. Its pretty common with fast-movers...one BIG to just go to monos, for hunting anyhow. Of course, lots of good bullets, just have to try one that likes your rifle's bore and speed...

 

[tankgijohn72]

That's some interesting stuff! I'd tag Hornady perhaps, or with your permission I can ask them. I'm sure folks would have all sorts of ideas, maybe they've actually seen it before?

No problem with me if you ask them. Would be interested in what they had to say. I also had some 135 bergers I put through the rifle. I know that it was having issues with stability. My first 12" 5 shot group at 100yd ever. Those did show a slightly out of round hole.

 

[Thunderrun]

I had the same thing happen with a 9mm pistol round @ 10 yards! Must be those 3,000fps rounds out of a 4" barrel... On a more serious note, it has me stumped as well. I hypothesized that maybe I had a split in the copper plating, but couldn't convince myself since it only happened once.