Projectile bad in short range but good for long?

[snipelango]

Hello! I was watching a video on YouTube, and the man said that there are pellets/slugs that perform poorly at close range but perform well at long range, and that they can stabilize with distance.
Is that possible?
Because if a pellet/slug doesn't group well at close range, it will be even worse at long range, since it's already destabilized up close, and this would only get worse with more distance, right?

[K.O.]

For a long time it had been debated about bullets going to sleep was true or not...Bryan Litz demonstrated using the 6 degrees of freedom model the mechanism that makes it possible...

simplified it is about center of gravity damping out yaw...

[NorCal David]

Well, there are other factors besides yaw. The people I have seen testing pellets usually test beginning with shorter ranges, eliminate those not grouping well, and test the others at more distant targets. Possibly this is because experience has shown they test worse at longer ranges. I am no expert on ballistics, but anyone can try this for themselves.

[Back_Roads]

 My experience the group may not get better but will stay the same at the longer range , vs a pellet that can get squirrelier on the way to the target as it is drag stabilized.

[TorqueMaster]

My understanding is:
With pellets -- if it's 1 MOA at 20 yards it will be no better than 1 MOA at 30, 40, 50...generally getting worse and worse the further out it goes.    This I get.
With slugs  -- they can be mediocre at 50 yards, lets say 2 MOA, and somehow magically tighten up at longer range, say 1 MOA at 100 yards.   I do not understand it, but have heard it from sources I believe.  I don't shoot slugs, so this is all just hearsay, but worth remembering if I ever do.

[Blowpipe Sam]

I shot PB's competitively for several years and I have never seen or heard of a projectile that shoots smaller groups at long rang than it will shoot at short range.  It is ballistically impossible.

[eeler1]

Theory v practice.  May be possible, but never actually happen in real life.

[splitbeing]

My experience the group may not get better but will stay the same at the longer range , vs a pellet that can get squirrelier on the way to the target as it is drag stabilized.

X2

Case in point: shooting my Akela .177 at 50 ft, its favorite pellets do better than slugs. At 70 yds, most pellets do poorly, the heavies do ok, the slugs are still tight.  100 yds, the slugs are still grouping and the pellets are a lost cause.

[subscriber]

I shot PB's competitively for several years and I have never seen or heard of a projectile that shoots smaller groups at long rang than it will shoot at short range.  It is ballistically impossible.

The question is not about shooting smaller groups at 50 than at 25 yards.  The question is about shooting groups that are lower MOA at 50 V 25 yards.  In other words, something like 1" groups at 25 yards and 1.5" groups at 50 yards, using the same airgun and pellets, under the same conditions.    Or 2" at 25 yards and 2" at 50 yards.

While the above sounds like perpetual motion, it happens when the projectile is wobbling or spiraling from the muzzle to describe a larger group, until the wobble or spiraling calms down.  That is what makes the group appear to tighten up with range. 

Obviously factors such as wind and pellet variations still open groups more as distance increases. There is no magic involved here.

Anyway, this phenomena has been observed for over 100 years, and is known as a "bullet going to sleep", when the wobble or spiral stops and the projectile travels closer to its average trajectory.

The difference is that pellets that are shot too fast, or more precisely, spin too fast as their forward velocity decays, tend to spiral wildly at longer ranges.  So, one needs to be careful not to mix different cases, and make absolute declarations.  The devil is in the details.

[subscriber]

We quantify group size by the max spread.  More sophisticated analysis looks at the shape of the group, or better yet, groups:

Round groups are preferred because combined dispersion factors are "balanced".  But, vertical and horizontal stringing can tell us more.  Vertical stringing may indicate shot to shot velocity variation, that is likely to increase with range.  Horizontal stinging may be due to variation in cross wind, that is likely to increase with range.

Barrel harmonics induce errors that would increase with range.   These could be in any direction with a given barrel, in a given assembly.  Some barrels with thimble transfer ports enable the barrel to be "clocked" on assembly, so that the "flick" or jump deflection on firing is in the vertical plane. 

If we are talking about spring piston airguns, they are so jumpy that holding them "correctly" is a larger factor that barrel flex (not hinge and lockup motion on a brake barrel).  That said, how you hold a springer does affect vibration throughout the system, including provoking more or less barrel and hinge play induced flex.   

Break barrel airguns tend to have stiff barrels because the barrel is the cocking handle.  While low cost PCPs tend to have very flexible straw barrels.  Thin barrels for their length have more deflection on the shot; even on a PCP, that has almost no shock and vibration, compared to a "springer".

[splitbeing]

Learning alot here. Thanks.

[Blowpipe Sam]

Sounds like old wives tails and "Voodoo ballistics" to me.

Essentia non sunt multiplicanda praeter necessitatum.  Occams razor never fails.

[avator]

Sounds like old wives tails and "Voodoo ballistics" to me.

Essentia non sunt multiplicanda praeter necessitatum.  Occams razor never fails.

Yeah, what he said... I think.   

[subscriber]

Perhaps an analogy will show that we do not believe in magic, or a free lunch:

If you have a foot diagonal image at 1200 DPI.  Resample that image at 300 DPI, while keeping the image size constant.  Then take the 300 DPI copy of the image, and save it at 1200 DPI.  Now, all you will have is a more blurry image.  Once you have lost definition or precision, you are not getting it back.  The system cannot perform better in the absolute sense from that point on.  But it can get worse at a lower rate.

The concept of a projectile settling is like watching a racing driver flick his steering back and forth to warm up his tires.  This, while maintaining an average path that is straight.  The car appears unstable, but it is going where it is supposed to, as if it were going straight.  Indeed, after the driver quits making rhythmic steering inputs, he travels straight.     If he had been traveling between parallel rows of cones, he would need a "wider lane" while sawing at the steering, than if making minimal corrections.  Consider cone lane spacing as group size analogs.   

[splitbeing]

Gotta love a sharp mind, whichever way you cut it [chuckling]

quantae tum scindunt hominem cuppedinis acres
sollicitum curae, quantique perinde timores!

Also, the driving metaphor makes some sense to me.  I feel a bit like a loopy projectile when wobbling my way to safer driving. 

There's that loopy word again!

[subscriber]

That Latin is Greek to me