Home Forums Hunting & Shooting Ask The Gunwriters BS or truth,LR bullets take a while to stabilize and can shoot better at longer range

What say you?

BS, they are spin stabilized not laser guided

Sounds like a parallax issue to me.

My take, based on my limited knowledge of the various sciences, is that they should be at the most stable they are going to be upon leaving the muzzle (at their highest speed). I would think that any spinning projectile, moving forward, would only tend to become less stable as it decelerates. I will await someone more knowledgable than myself to see if my pseudo-educated guess is correct.

Hell if I know…but this is an interesting discussion.

The stability factor actually does increase at range. The angular velocity of the projectile decreases more slowly than the linear velocity, so the aerodynamic forces on the bullet decrease faster than the gyroscopic stabilization.

Read up on bullet coning motion. Supposed to be its greatest at the muzzle. Settles out down range. Several good research articles on it, even Sierra admits it’s possible.

And there you have it, just that for which I was waiting. You (I) learn something new every day. Very interesting.

The aerodynamic forces acting on the nose are what tend to destabilize a bullet in flight so anything that reduces those forces helps the bullet maintain its nose-on flight. As mentioned above, slowing down makes it more stable because the spin rate decays at a much slower rate then the velocity. Climbing in altitude with less dense air helps as well. Mule Deer has addressed this pretty well a few times.

Swifty52 has it right.

Aerodynamic forces make the bullet spiral very slightly, out to about 200 yards.

Interesting. Makes me wonder if little vortex generators on the plastic tips of some bullets would smooth out the air flow over the bullet?

I didn’t read all the comments but I’m of the opinion that the bullet rotates around its center of mass going down the barrel and a slight yaw maybe induced from the chamber to engaging the rifling. After leaving the barrel I believe that it takes a little while for it to start rotating around its center of gravity and have found that bullets from good barrels and a good load that’s been worked up tend to shoot better at distance when measuring group size

That is showing degrees of yaw or where the nose of the bullet is pointing, not the flight path of the bullet. The diagram on the right is showing where the bullet actually went. It started diverging as soon as it left the muzzle and continued to do so. Once the deflection starts, it won’t get any better. There is nothing acting on the bullet to make it “go that way to hit the target”.

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The video is the answer the first part of the question. And you correctly answered the second part. Bryan did a lot of experiments using shoot through targets to prove that group size doesn't shrink with distance.

i have wondered this some too i have noticed this just a little with my 257 Weatherby mag. with 100 gr. bullets at 3800 FPS. that at 100 yds. bullets seem to be very slightly key holed and at 150 yds. and beyond these bullets seem somewhat perfect bullet holes. is this possible ? would different barrel twist either faster or slower make a difference ?

I recently published an article on flat-base versus boattails:

1) Boat-tailed bullets do tend to destabilize more when leaving the muzzle than flat-based bullets, due to more powder gas blowing by the angular base during muzzle exit. This is why short-range benchrest bullets are flat-based, or have very slight boattails.

2) But te reason higher-BC bullets tend to group better at longer ranges is not primarily because they take longer to "stabilize," but because they drift less in wind.

3) Most shooters (especially hunters) don't get this: Instead they assume groups are relatively larger at ranges beyond 100-200 yards because bullets are becoming "destabilized" as they slow down.

4) This is actually the opposite of what happens, because bullets in flight are affected by two different forces: air pressure on the front end, which tends to destabilize bullets, and gyroscopic stability from the rifling twist. Velocity slows much faster than bullet spin, so bullets fired from a sufficient rifling twist become MORE stable at longer ranges, due to lower pressure on the nose--at least until they drop to around the speed of sound, which doesn't happen with typical hunting bullets.

5) Wind-drift increases at about twice the rate of range: A bullet that drifts half an inch at 100 yards in a 3-mph wind will drift around 2 inches at 200 yards in the same wind--and 8 inches at 400 yards

So yes, boattails can be less accurate at shorter ranges, but become more accurate at longer ranges due to less wind-drift. And most hunters have no clue how much even a 3-mph breeze (often consider "calm air") can drift a bullet even at 100 yards. Since wind is rarely absolutely steady, groups "open" up at longer ranges, unless the shooter can compensate accurately.

MD nailed it. There’s also - changing from above the speed of sound to below the speed of sound - note that 22 LR target ammo starts at below the speed of sound.
If I knew the reason for this, I forgot.

My head hurts taking all this in...how about an amusing anecdote for those of us in Rio Linda? Some years back when the Commonwealth countries were still using .303's in competition, it was common knowledge that the Mk7 .303 174 gr ball round was barely capable of holding 2,5 moa at 100 or 200 yards. But, it got better at 300 and , Katy bar the door at 600, theory was the damn thing straightened up and flew right. Embarrassing several competing countries, including us Yanks.

The groups didn’t get smaller but the MOA did, right?