Elongated holes at close range. Why???

[Steve Janes]

So I'm doing drills with my Swiss the other day at close range, like 2-3m, and I started seeing some elongated holes in the cardboard. Maybe 3 out of 20. Looked like they hit the cardboard completely sideways. At this range, I have no idea how the rounds would get turned that way unless they were coming out of the barrel already sideways, which I can assure you is not happening

The Ammo was Norinco 5.56 55gr M193, The rifle is my Non-restricted Classic Green with a 1in7 twist.

Target was at 2-3m, leaning up against a dirt backstop, so the cardboard is pretty much touching the dirt backstop.


Now at first I thought maybe under stabilization but the rifle and ammo group up nice and tight from 25-50m and inside 2 inches with iron's at 100m, and I shoot at 200-400m regularly and get decent accuracy there too, so stabilization at range is not an issue, I've even taken the norc ammo to 500m with the 1in7 and got 80% hits. So I don't think it's a stabilization issue.

Interestingly I tried this with AE 55gr bulk box, and it stopped happening. So it's definitely got something to do with the ammo, and yet the same stuff groups fine from 50m on out to 400+ so why am I getting elongated holes in close like this?

Is it possible that the Norc 5.56 is tumbling on impact, kind of like M193 is supposed to in tissue at high velocity? So far I don't consider this a bad thing as the ammo groups up good at range, but appears to be very devastating at close range.

EDIT, On examination of the target, it was 2 elongated holes, out of about 50-60 rounds

 

[*MALICE*]

I would be highly skeptical that the bullets are hitting cardboard and then tumbling fast enough to keyhole.

With long distance target shooters, you hear about bullets taking time to 'settle down' or stabilize and people getting crap groups at closer distances but then they are nice and tight further out. Maybe something along those lines?

 

[Steve Janes]

I would be highly skeptical that the bullets are hitting cardboard and then tumbling fast enough to keyhole.

With long distance target shooters, you hear about bullets taking time to 'settle down' or stabilize and people getting crap groups at closer distances but then they are nice and tight further out. Maybe something along those lines?

Oh I'm skeptical about it too, I can't figure it out

Just checked the log Barrel has had just under 4000 rounds down the pipe, very clean, not worn at all.

That is kind of what I was leaning towards, but from 15m-50m I've never noticed this before, so why would it only happen this close? If the occasional round were already this side ways at 3m, I don't think it would have a chance of "Stabilizing" and hitting a target at range

 

[*MALICE*]

I re wrote what I typed because I misread what you wrote

 

[jethunter]

The bullets aren't stabilizing until they are somewhere beyond the range you were seeing the elongated holes. Like a spinning top, the bullet can correct some wobbles with the centrifical motion and that is most likely what you are seeing. It's fairly common - if it's stabilized at longer ranges then you have no problem. Might be that the barrel crown is ever so slightly off square with the bore. Possibly you or your gunsmith can check the crown but otherwise i wouldn't worry about it if it's working well for you at longer range. Unless of course you are entered in a 3 meter bench rest competition. LoL.

 

[Steve Janes]

The bullets aren't stabilizing until they are somewhere beyond the range you were seeing the elongated holes. Like spinning top, the bullet can correct some wobbles with the centrifical motion and that is most liely what you are seeing. It's fairly common - if it's stabilized at longer ranges then you have no problem. Might be that the barrel crown is ever so slightly off square with the bore. Possibly you or your gunsmith can check the crown but otherwise i wouldn't worry about it if it's working well for you at longer range. Unless of course you are entered in a 3 meter bech rest competition. LoL.

I understand what your saying, and it makes sense.

 

[C77]

I have seen this many times with a bad lot of ammo. If the projectile was assembled shoddily, it may not ever stabilize. If you get key-holeing at longer range with that and not with others it might be a bad lot of ammo.

 

[Steve Janes]

I have seen this many times with a bad lot of ammo. If the projectile was assembled shoddily, it may not ever stabilize. If you get key-holeing at longer range with that and not with others it might be a bad lot of ammo.

Yes but they seem to stabilize consistently at range. The only time I see elongated holes is when shooting at less than 5m

I considered the possibility of a bad batch of ammo too. But I would like to be sure, if it's even possible.

I think I can accept JetHunter's explanation. The spinning top reference gave it to me, it's like the round is wobbling before it can stabilize, then the velocity and spin take over and stabilize the wobble. If a round were to hit cardboard at close range while still wobbling, it could and most likely would leave an elongated hole.

 

[*MALICE*]

Steve - You seem to have a whole lot of weird problems with your Swiss guns

 

[Steve Janes]

Steve - You seem to have a whole lot of weird problems with your Swiss guns

I know I know, give me the best platform in the world and I will use it hard enough to feck it up somehow. I'd love to break, ahem, own an hk416, but I''m sure I''d break that somehow too. I broke a mini-30 too, did ya hear about that one. I break every rifle I touch it seems. Or at least something goes wrong with them once I get my hands on them. Keep me away from yours is all I have to say.....LOL.......I have secretly been dreading the day when something does go wrong with the Classic Green, if it were to crap out on me like the Black special did, I'd be so choked, but alas, I've never had an issue with this one. Here's hoping it stays that way!!!

To be fair to the rifle (and in case I ever try to sell it) this isn't actually a problem, just me getting schooled about some stabilization stuff. As everyone has said, it's quite common, and the rounds are grouping tight beyond 10-15m once they've stabilized. I'm happy with that!

 

[C77]

Yes but they seem to stabilize consistently at range. The only time I see elongated holes is when shooting at less than 5m

I considered the possibility of a bad batch of ammo too. But I would like to be sure, if it's even possible.

I think I can accept JetHunter's explanation. The spinning top reference gave it to me, it's like the round is wobbling before it can stabilize, then the velocity and spin take over and stabilize the wobble. If a round were to hit cardboard at close range while still wobbling, it could and most likely would leave an elongated hole.

Yep. If they are stabilized at longer range might be true. 5.56 mm takes up to 50 m to stabilize. Typical yaw is only around 5 degrees max however.

 

[mmattockx]

Yep. If they are stabilized at longer range might be true. 5.56 mm takes up to 50 m to stabilize. Typical yaw is only around 5 degrees max however.

This ^^^. If bullets are leaving true side profile holes there is no way they will ever stabilize and fly point forward farther downrange. I don't know what is happening with OP's projectiles, but it is not a case of the bullets going to sleep downrange but keyholing up close.


Mark

 

[Dietz]

Do you have pictures of the holes? Are you sure they are actually keyholing? I highly doubt the bullet could make a 90° rotation sideways at 3m from the muzzle. Unless it's very, very, very badly altered.

 

[Brutus]

Points at an ammunition issue from your own info right?

 

[Steve Janes]

Do you have pictures of the holes? Are you sure they are actually keyholing? I highly doubt the bullet could make a 90° rotation sideways at 3m from the muzzle. Unless it's very, very, very badly altered.

This ^^^. If bullets are leaving true side profile holes there is no way they will ever stabilize and fly point forward farther downrange. I don't know what is happening with OP's projectiles, but it is not a case of the bullets going to sleep downrange but keyholing up close.


Mark

Mark: I would tend to agree, and yet they are stabilizing and flying straight downrange.

Sorry about the size, shot were taken at a downward angle, at about 2-3m. NOTE: ignore the shots surrounding the elongated holes, as they are not from the same shooting session, this target has been used for weeks over and over and over.

I had to peel the tape off the target so this is the best I could do, is it possible that due to the round not having stabilized yet (wobbling), it is increasing the chance of it to tumble on impact? A crazy thought I had was maybe the odd round was bouncing off the back stop and coming back through the target but I didn't get shot so.....

 

[spooksar]

I know I know, give me the best platform in the world and I will use it hard enough to feck it up somehow. I'd love to break, ahem, own an hk416, but I''m sure I''d break that somehow too. I broke a mini-30 too, did ya hear about that one. I break every rifle I touch it seems. Or at least something goes wrong with them once I get my hands on them. Keep me away from yours is all I have to say.....LOL.......I have secretly been dreading the day when something does go wrong with the Classic Green, if it were to crap out on me like the Black special did, I'd be so choked, but alas, I've never had an issue with this one. Here's hoping it stays that way!!!

To be fair to the rifle (and in case I ever try to sell it) this isn't actually a problem, just me getting schooled about some stabilization stuff. As everyone has said, it's quite common, and the rounds are grouping tight beyond 10-15m once they've stabilized. I'm happy with that!

I must shoot with your long lost twin brother, every gun he touchs something goes wrong

 

[Master-G]

That looks like classic keyholing...weird. You say the ammo groups OK at longer ranges--have you checked to ensure that all of the rounds are accounted for on target? If what you're seeing at close range happens only 3 in every 20 rounds or so maybe at longer ranges the rounds aren't even hitting the target. I would be very tempted not to use any more of that ammunition in your rifle.

 

[Steve Janes]

That looks like classic keyholing...weird. You say the ammo groups OK at longer ranges--have you checked to ensure that all of the rounds are accounted for on target? If what you're seeing at close range happens only 3 in every 20 rounds or so maybe at longer ranges the rounds aren't even hitting the target. I would be very tempted not to use any more of that ammunition in your rifle.

They are definitely hitting the target at range, 10 for 10 inside a fist sized group at 150m yesterday, after sprinting that same 150m. I did this at about 4 times, taping the target after each run, every round was accounted for.

My theory is the downward angle, combined with lack of stabilization at 2-3m, is cause this "wobble" to make the odd round tumble hard on impact.

 

[Brutus]

It's almost as if the bullet is not compatible to the barrel twist rate?

But I believe more of this is really just poor quality ammo from the get-go.

Edit: There was a fella up here who shot very often his M4 copy and the same Norinco ammo and he started to grind it out at slightly longer distances. (200-300 meters)
A few weeks late late we often found his unfired ammo literally thrown away.

 

[marsden]

Mark: I would tend to agree, and yet they are stabilizing and flying straight downrange.

Sorry about the size, shot were taken at a downward angle, at about 2-3m. NOTE: ignore the shots surrounding the elongated holes, as they are not from the same shooting session, this target has been used for weeks over and over and over.

I had to peel the tape off the target so this is the best I could do, is it possible that due to the round not having stabilized yet (wobbling), it is increasing the chance of it to tumble on impact? A crazy thought I had was maybe the odd round was bouncing off the back stop and coming back through the target but I didn't get shot so.....

lol,holycrap! Put a new target up now and again. What kind of back stop? very strange.