Comments on: Tuesday Trivia: Can You Over-Stabilize a Bullet?

By: phil

phil — Fri, 01 May 2020 21:57:17 +0000

I guess that the over stabilization will always happen even for small arms, it is just a matter of how much this effect can be seen on the bullet trajectory.
Physics doesn’t change for small arms or artillery: a rotating body will have a gyroscopic effect that will try to keep the initial orientation. This means that also for small arms at the end of the trajectory the bullet will be flying with a certain angle of attack that will influence the drag coefficient.

The answer is probably that, although this effect can happen, the overall effect on small arms bullet trajectories can be neglected.

By: Phil

Phil — Fri, 01 May 2020 06:39:19 +0000

I think that physics doesn’t change between small arms and artillery shells, it is just a matter of how much an effect has influence on the physic system.

It is undoubtful that an object with higher gyroscopic momentum will try to keep the initial attitude, which would ideally coincide with the barrel line. This means that at very long ranges, whrere the drops are higher and barrels are pointing “up” to compensate, the bullet will fly with a certain amount of angle of attack that could cause detrimental effects on the drag coefficient. Obviously this could have a very little effect if the angle is small (as reported in previous answers), but it will be there.

So, in my opinion, you can over stabilize a small arm projectile, but its effect will be very limited.

By: David Lawson

David Lawson — Fri, 01 May 2020 02:26:55 +0000

Very fast twist rates can spin the occasional projectile till it breaks up. If you are willing to accept that and the miss from time to time then go ahead.

By: billy underwood

billy underwood — Thu, 30 Apr 2020 13:03:00 +0000

I would have thought the article would have answered the question, instead of just creating another discussion.

Post the correct answer, please.

You use the name Bryan Litz and people expect to have an answer.

By: Daniel Steven

Daniel Steven — Wed, 29 Apr 2020 19:21:49 +0000

True. From my research it causes the bullet to fail to track the nose on course of the trajectory and you have the bullet falling horizontal rather than more vertical, you want it to keep tracking like a missile, not like a Football.

By: Bryan S Litz

Bryan S Litz — Wed, 29 Apr 2020 14:34:45 +0000

False.

Small arms bullets will ‘trace’ with the trajectory regardless of stability factor.

The myth of over-stabilization likely comes from large caliber artillery guns with very high angles of fire. Occasionally with those projectiles which way 100’s of pounds, and are launched over 30 degrees, they reach heights where the air is thin, and the projectile velocity at apogee is slow (very low dynamic pressure to orient the projectile) and the moment of inertia is so high (a lot of spinning mass) that such a projectile can ‘fail to trace’, and fall to the ground base first. This would cause the round to fall short (possibly on friendly forces vs. the enemy) and likely fail to fuse (round needs to impact point first for an impact fuse to detonate the round).

But there are a lot of differences with small arms. Bullets are much lighter, don’t slow down at apogee, don’t get that high, etc. In fact, the more stable a bullet is, the better it will keep its axis aligned with the flight path.

Academics aside, live fire radar tracks of small arms rounds show reduced drag for all speeds, especially transonic, for bullets fired from faster twist rates, all else equal. This includes on the downrange (falling) portion of the trajectory.

Thanks for bringing this back, it’s been a while since we did trivia!

-Bryan

By: John

John — Wed, 29 Apr 2020 14:09:57 +0000

Statement is true.
Over-stabilized means that the projectile stays pointing at the angle it is launched at, rather than the nose following the trajectory.
This means the bullet flies nose up at the end of it’s flight increasing it’s drag. Longer flight time than an optimally spun bullet, so more wind drift, and elevation required.

By: Mark Sundell

Mark Sundell — Wed, 29 Apr 2020 14:06:52 +0000

Yes, but not trivial only at long ranges. Theoretically, at peak altitude on the trajectory parabola, if the bullet does not tip point first into the downward leg, the BC and other factors will dramatically change and the circle of impact will be dramatically enlarged.

By: Michael Moore

Michael Moore — Wed, 29 Apr 2020 11:43:56 +0000

False, bullet will not consistently fly tip high from being over stabilized.

By: Phill

Phill — Wed, 29 Apr 2020 05:30:33 +0000

True.