Bullet Attitude at Impact

[Mitch Rapp]

I have seen several recent threads about bullets and some really good tests of bullets at high and low velocity. The low velocity impacts are what got me thinking. If I understand it correctly a bullet maintains it's attitude in flight, unlike say an arrow which follows the arc. In other words, at very long range a bullet would have a nose up attitude on impact. Does that change the performance of the bullet? How would you test that? and has anyone tried?

More of a curiosity than anything, just not something I have ever seen talked about.

 

[ShtrRdy]

I'm not an expert in this area, but from reading Bryan Litz's book on Applied Ballistics, it sounds like for a properly stabilized bullet, the nose of the bullet will be pointing in the direction of travel. Have you ever noticed a football thrown by a pro? How the nose of the ball follows the arc of trajectory? It's the same principal.

The book mentions that over-stabilized bullets can have an over-riding effect of resisting some of that natural pointing. In this case the tip of the bullet can be pointing off slightly from the direction of travel.

To have the nose of the bullet pointing the direction it was when it left the muzzle - no, it doesn't do that.

 

[Mitch Rapp]

I'm not an expert in this area, but from reading Bryan Litz's book on Applied Ballistics, it sounds like for a properly stabilized bullet, the nose of the bullet will be pointing in the direction of travel. Have you ever noticed a football thrown by a pro? How the nose of the ball follows the arc of trajectory? It's the same principal.

The book mentions that over-stabilized bullets can have an over-riding effect of resisting some of that natural pointing. In this case the tip of the bullet can be pointing off slightly from the direction of travel.

To have the nose of the bullet pointing the direction it was when it left the muzzle - no, it doesn't do that.

Never thought of the football example but it does make sense.

 

[rcoody]

think about this. look at the trajectory graphs of a bullet. That bullet is falling pretty fast out there at 800 to 1000yrds. If you are shooting at game at those ranges you should take that into account. Don't aim at that magic point right behind the shoulder. Aim higher like mid body because that bullet will be in a downward trajectory when it strikes.

 

[FEENIX]

In other words, at very long range a bullet would have a nose up attitude on impact.

Agree with ShtrRdy and rcoody. Unlike an aircraft, the bullet as it is propelled out of the rifle, does not have the ability to propel forward with the nose up attitude like aircraft's angle of attack (AOA), not to be confused with a climb.

 

[Mikecr]

I agree with ShtrRdy and rcoody too

 

[Zen Archery]

Do a search on Magnus Force.
Bullet direction of travel, center of gravity, and axis, will cause bullet to yaw.
More importantly to you specific question. Bullet companies and manufacturers will publish minimal FPS and minimal LBS necessary for bullet to expand properly. Target bullet's are designed to perform differently then hunting bullets.

 

[Mitch Rapp]

Well it seems like I was working under a faulty premise. Lol. So only if a bullet is over stabilized will it maintain the angle it was fired at?

The reason I thought this was I heard a sniper explain why a .50 call round is so devastating at long range (not that it needs much help) but he said because of how far it has fallen it strikes the target at an angle, which he explained the way I did in my initial post, and it sort of made sense so I ran with it.

Thanks for the clarification!

 

[Laelkhunter]

Not really sure about the technical stuff. When I shoot at a distance (in excess of 200 yards), it is at a paper target, usually checking the group size. All of the bullet holes seems to be concentric, and not elongated. If the bullet tip was in a Nose high attitude, I would think the hole in the target would be elongated- Or am I just not understanding the discussion and oversimplifying ??

 

[FEENIX]

Maybe this helps ...

https://www.youtube.com/watch?v=VqOqZBRZsj8

 

[ohiohunter]

Well it seems like I was working under a faulty premise. Lol. So only if a bullet is over stabilized will it maintain the angle it was fired at?

The reason I thought this was I heard a sniper explain why a .50 call round is so devastating at long range (not that it needs much help) but he said because of how far it has fallen it strikes the target at an angle, which he explained the way I did in my initial post, and it sort of made sense so I ran with it.

Thanks for the clarification!

No, if it is stabilized, not necessarily over stabilized, the bullet will maintain a path directly behind the nose. Basically a perfect spiral. If it is under stabilized as mentioned it will yaw, look like a dead duck, resulting in an erratic inconsistent wobble (kind of like the carlton dance) where the nose no longer precedes the body thus reducing accuracy and terminal performance.

Earlier you, or someone, compared a bullet to an arrow. They are one of the same in that they both follow a path relative to speed distance and gravity. They are both unpowered projectiles following a parabolic path. With adequate FOC on an arrow your tip will always lead the shaft.

The 50 cal example he is siting as most devastating is that long shots result in bullets "dropping" into the target. VS taking on targets perpendicularly which is virtually impossible. I really think you just read too much into a sniper's personal theory. A 50cal packs so much energy that the angle of attack means virtually nothing as long as you hit your mark.

I say this b/c if you decrease the angle of attack you have to be closer to the target which will result in higher impact velocity and consequently more energy.

 

[FEENIX]

Angle of attack is not the same as angle of trajectory.

 

[ohiohunter]

Angle of attack is not the same as angle of trajectory.

Please elaborate? The trajectory determines the angle of impact/attack.

 

[FEENIX]

Please elaborate? The trajectory determines the angle of impact/attack.

Again, angle of attack and changing the angle of trajectory is not the same; i.e., an airplane can have 15 degree AOA (nose up) maintain a forward motion at that attitude without climbing.

Point the rifle or bow from 0 to +45 angle and you change the trajectory to POI X.