Tumbling bullet.

purdeydog

Well-Known Member
IMG_2175.jpg

Hope picture has attached. Thought I might share this photo. It's of a .308 Berger 185g fired today. It was at a hardox target at 1430y. I missed more that I hit. Misses were all round the target when I looked. I found this guy just laying on the dirt. Tumbling at that distance and impacted the dirt on its side I reckon. It left a divet next to the bullet and bounced back out to lay on the dirt I reckon or just clipped the target or target frame. Interesting I thought. It's a good bullet at closer distances it groups really well.
 

Dalua

Well-Known Member
I wonder whether it had in fact clipped the target or frame with its rear end. It would presumably be dropping quite steeply down and towards the target at that range having dropped to subsonic some time before getting there.
Would it actually be tumbling, though?
 

Yorric

Well-Known Member
That has a similar bend to the "Bisley bananas" often found in the butts, they sometimes are the result of mantlet strikes. Bullets hitting soft ground at a low angle riccochet upwards then fall to earth bent --- Except yours looks like it has hit something hard & sharp at quite a speed almost side on causing the big notch in the jacket. At that range it would be traveling somewhat sideways as it dropped, possibly hitting a flint or something as it landed. That could explain the divot too.
A way to indicate whether a bullet is tumbling is to have a card target & look at the hole shapes. -- Tumbling bullets often pass through sideways leaving bullet shaped holes with the tips randomly orientated. Stable bullets would leave almost round holes with any pointed shape orientated upwards.

Ian
 

purdeydog

Well-Known Member
I'm not sure to be honest. Ive read they can keyhole or tumble when unstable. Not sure when that round reaches that point. Can't be from off it.
 

purdeydog

Well-Known Member
That's an interesting reply Ian. The divet it was in front of had a peace of smashed flint in it. We thought it might of hit that and bounced out.
 

enfieldspares

Well-Known Member
IMHO it's caused by these THREE things. Which are really two things.

Bullet too long for the twist rate/twist rate not correct rate for the bullet length.

So that's one thing expressed two ways. Nosler Partition are culprits in this respect....too "long".

Got continual tumbling trying to use 100 grain Partition in my 6mm Remington.

Bullet driven at too slow a muzzle velocity EVEN THOUGH the twist rate is correct for that bullet weight and profile.
 
Last edited:

Ben1987

Well-Known Member
My understanding of aerodynamics is limited and my experience of shooting at 1400yds is none existent but as I understand it your bullet is whizzing along at supersonic speeds for X many yards, it then goes through an unstable plane of transonic flight where it starts slowing down and the shockwave caused by going supersonic catches up with it as well as air speeds being different at different points of the bullet, then once in the subsonic stage any instabilities picked up during the transonic transition are excentuated which can lead to the bullet tumbling. Imagine a spinning top, once it's spinning it spins on a vertical axis perfectly until it starts to slow then it gradually starts wobbling as it slows.
 

Ray7756

Well-Known Member
I may well be wrong but I thought that once the bullet had stabilized it stayed thay way, ( i have had bullets that wont stabileze in my 22 hornet) best way to check is set up some paper or cardboard around your hardox target, as you say your were hitting around the target and throw a few rounds downrange if you hit the soft targets you will see if rounds are tumbling, would love to hear of the results
Cheers
Ray
 

Milligan

Well-Known Member
I may well be wrong but I thought that once the bullet had stabilized it stayed thay way, ( i have had bullets that wont stabileze in my 22 hornet) best way to check is set up some paper or cardboard around your hardox target, as you say your were hitting around the target and throw a few rounds downrange if you hit the soft targets you will see if rounds are tumbling, would love to hear of the results
Cheers
Ray
Normally, yes, but in this case we're talking about the bullet running out of steam at 1.4km or so.
As it slows it wobbles or yaws on axis, debate is whether it then tumbles.

In my experience bullets do strange things. The bent one in the pic could even have been hit by another bullet.
 

Top