Balanced flight bullet?

[grayfox]

I don't know about bullets that can adjust in flight..... but the realllll loooooooooooong distance kills have been with major caliber rifles, right? like 50bmg, sniper grade rifles, et al. I don't think the Grendel range is going to present that type of distance performance for you.
Again, for ethical hunting distances, there are several excellent bullets for the Grrrrr. One deer kill was 502 yds, one elk was taken at 390+ yds... I doubt if either shooter had any bullet balance-equations in mind for those shots.
And steel banging IIRC in the neighborhood of 800-1000 yds...
Not knocking the theory mind you, just not real sure how it is relevant for this cartridge in the real shooting world...

[LR1955]

I will keep digging on past threads, was checking to see if anyone had a known/found a particular bullet for the grendel that had the balanced rotational and linear spin drag factors that would produce balanced flight through the full spectrum; of course the appropriate twist rate is another major factor needed. ..... I just have to find that proper triple point where things exist as a gas, liquid, and solid all at the same time....

In other searches I did not look deeper into heavier projectiles I saw as they are more fitting for the Creedmoor and other lager various 6.5mm cases, some others in .30 cal.

Not sure if the guys making those record kills at ....what was that.... 3.5 km or something the last one i heard of?.... are using well designed ammo / barrel combo that produces balanced stability through the entire flight from super to trans to sub? Has any info been released for actual use of that bullet claimed to be able to adjust in flight?

NB:

I believe LRRP52 answered your question. Not sure what it is you expect from a Grendel. I doubt a bullet fired from a Grendel case can go 3 1/2 K.

You better believe that guys who shoot extreme distances will be doing so with custom rifles, cartridges, and probably lathe turned bullets.

With a Grendel, a 30 grain cartridge and what would be considered medium or low velocity by today's standards, you won't be shooting far enough where you should be agonizing over 'balanced rotational and linear spin drag factors'.

Also, from what I understand, the rotational spin of a bullet does not decay enough over its time of flight to make a difference. If the bullet was spun fast enough to be stable when it left the barrel, it will stay that way until it hits the ground. May be yaw and pitch but that would be because the shooter choose a bullet that wasn't a good fit with the twist of rifling or velocity.

So, not sure what it is you are asking anymore.

LR55

[NugginFutz]

newb - just what is it you are interested in doing with the 6.5 Grendel that makes this subject even notionally relevant? I've shot multiple bullets/styles/weights within the generally accepted envelope of 6.5 Grendel Performance and have yet to experience any stability issues. I suspect you're trying to over think this.

[newb]

Steel at 1 mile for fun is the only purpose.

A new barrel with appropriate twist rate would be in order for this, but am in research phase to very the balanced flight through transonic is achievable with offerings that will fit in grendel before i took the leap.

Predator down was successful out to the "magic mile" but I also recall at one time him making comment about instability opening up his groups below supersonic: Amax bullet.

As prev mentioned, one theory on it I read discussed the projectile needed to decelerate rotational and linear velocity at the same rate, in conjunction with the right twist rate to begin with.

I surmise it pissible someone may still attain good stability without having that matched deceleration rate, as long as they can balance all the variables enough one way or another.

So my question was, if anyone had already found the trick to accomplish it with the grendel and what bullet.

Hopes this help clarify things.

And I will keep searching posts, I will have more time for that in the near future.

[newb]

Grayfox- not avail to civilians that i know of, but check this out for path correcting bullets.... (which on a side topic i was wondering if possibly those record sniper kills were made with or did they do it with a balanced flight set up)

https://en.m.wikipedia.org/wiki/Smart_bullet

[A5BLASTER]

Steel at 1 mile for fun is the only purpose.

A new barrel with appropriate twist rate would be in order for this, but am in research phase to very the balanced flight through transonic is achievable with offerings that will fit in grendel before i took the leap.

Predator down was successful out to the "magic mile" but I also recall at one time him making comment about instability opening up his groups below supersonic: Amax bullet.

As prev mentioned, one theory on it I read discussed the projectile needed to decelerate rotational and linear velocity at the same rate, in conjunction with the right twist rate to begin with.

I surmise it pissible someone may still attain good stability without having that matched deceleration rate, as long as they can balance all the variables enough one way or another.

So my question was, if anyone had already found the trick to accomplish it with the grendel and what bullet.

Hopes this help clarify things.

And I will keep searching posts, I will have more time for that in the near future.

So you want to hit steel at a mile with a grendel?

This is probably your best bet.

Handload 123 scenar as fast as you can go and still get 1/2 5 shot groups, buy the best of the best 24 inch barrel, install it under the best of the best scope and mount and drop in the best of the best trigger.

Have the barrel done up with 8 or faster twist.

Once you have all that find you a 1 mile range at or above 6000 feet above sea level. And have at it.

Too me that is your best chance of achieving it with a grendel.

Or just buy a 6.5 creedmoor bolt action and get there cheaper and easyier.

This is the only reason I would choose creedmoor over grendel.

Short and simple but hope it helps sir.

[grayfox]

Well, I decided to try looking up "balanced flight", and turns out it is a patented concept:
"Conditions were identified that could be translated into projectile design, which would exhibit very long distance accuracy. The concept is called Balance Flight and is patented (6,629,669)" https://cheytac.com/the-cheytac-advantage/

[grayfox]

Pursuing this a bit further I may have found at least one answer: Warner Tool Company has a line of monolithic, custom turned bullets in several diameters, there is a Precision Rifle Blog article that discusses some of their .308 line.

https://precisionrifleblog.com/2016/02/28/flat-line-bullets-4700-yard-shot/

Going to the WTC website they list their available bullets, one of which is a 121 gr 6.5 projectile. G1 BC doppler, 0.637, G7 doppler 0.318. Bullet length 1.462 in.

[(Edit to add): their stated cartridge OAL is 2.450.]

Their price is $62.40 per box of 50.

They also have a load data sheet for the Grendel.
So there appears to be at least 1 bullet for you.
But I could not tell whether it is an actual patented, balance flight bullet design.

[newb]

The patent is there, but has been challenged I believe because as you mentioned some 30 cal already were achieving it.

In another location there is info about a Moller guy some where in the mix that raved and produced a bullet that was supposed to be the shiznit based off of simulation programs, etc. But was never practical tested before released, and it fell on it's face/ wouldn't group worth beans.

I saw the warner but haven't measured if those would have to be single loaded or not, or need extra free bore. I don't recall if those also have the drawback of not a good seal allowing a lot of blow by. I've seen a bunch over the past few weeks of digging so I have to revisit them to refresh my memory.

Other promising ones were in the creedmoor realm and that is future build so I didn't dig further. Going bolt with possibly IOR Crusader or Terminator for glass.

I did reach out to another individual to tap his knowledge base. He's pretty busy so it might be a while before I hear back.

In the mean time, I suppose I will start to gather the various promising looking bullet's detailed data that will work for the gendel and crunch all the numbers in the formulas myself.

[grayfox]

I don't have the formulas, but even looking at the WTC bullet, its COAL is too long for the grendel cartridge.
Others chime in but I've not heard of any Grrr cartridge at 2.450". Some guys I think may have talked in the range of 2.400 but those are bolt action, single loads, IIRC.
You're much better probability wise to think Creedmoor even with the WTC, or maybe 260 to give you that oomph... or the 6.5 PRC. 6.5 is a pretty good length/diameter ratio to give great ballistics.
But again no info on whether any 6.5's are truly that "balanced flight" or not.
But a 408 or 50 cal for reaching a mile... now there you go.
Build it before the Dems and 'casio-cortez (didn't cortez invade/ravage Mexico??) outlaw them all!!!

[grayfox]

The closest 6.5's I know of (there could be more), strictly from a BC standpoint, are like the Hornady's, 140 Eldm and 147 Eldm. (the "Mach 2.25" G values...):
the 140 G1= 0.646 , G7= 0.326
147 eldm, G1= 0.697, G7= 0.351.

Both of these entries have better BCs than the WTC above. Even their "Mach 2.0" BC's are better than WTC. But that does not assure that they are "balanced flight", just better BC's.

To get anywhere close to those #s in 30 cal you have to go to a 200gr-class bullet

ETA; It is still my humble opinion that you will touch the pot-o-gold at the end of the rainbow before you find the Grendel-balanced-thingy you're seeking.

[newb]

ETA; It is still my humble opinion that you will touch the pot-o-gold at the end of the rainbow before you find the Grendel-balanced-thingy you're seeking.

That has been my same thought as well. But I figured I'd ask the horde if any one by chance happened to know and also do my due diligence with a bunch of other side research.

Looking at the patent, some of the drawings show rifling marks on the bullet that appear to be more riflings than typical, which in theory could create additional rotational drag. Mentioned in the body of the patent also says the length, depth, and number of lands and grooves produced by the rifling. But those could also create some other unintended consequences not mentioned.

If nothing else, this will at least be a good learning exercise with all the research and number crunching.

[newb]

Update for any interested.

I found a recent vid that describes some of the thoughts on it. Less twist rate with heavier bullets. Produces less gyroscopic stability in the short term, but makes up for it in dynamic stability in the long term.

I can get a 27" Brux barrel for ~ $300 for my bolt gun .338 lapua (plus what ever the additional machining will cost) and Grendel about the same. One day I might have to try this theory. The reason I inquired for the Grendel is because it is much cheaper to shoot/ experiment with and by the end of the experimenting the savings could pay for themselves vs just the cost of .338 ammo alone.

Years back a coworker mentioned using 1:9 twist with I think 77 gr bullets in .223 wylde for long range shooting. It struck my curiosity as most people use 1:7 with high gr bullets. But I think I see why....

https://youtu.be/gJ9qZKf31Ic

[Jeepster18_88]

Your question makes sense after I understood what you were asking. I'm not a long range shooter but I understand the situation. Basically why you have 22lr subsonic match loads because they lose stability once they hit that transition speed. I loaded a bunch of Trailboss loads a few years back in everything from 38 spl to 270 and 30'06. The muzzle velocity out of the 270 was around 1300 for and IIRC, about 1100 out of the 30-30. They call them cowboy loads but all of them were very accurate. Something like this could be used to lower muzzle velocity down to a level where you could test accuracy difference during this transition, without having all the other factors to muddy up the testing.

[Popeye212]

I think you just have to put them in the freezer

Yep, Cryo bullets fly straighter.....