Niche reloading topics

[User00044]

Without testing , any statement regarding the ELD-VT's would be pure conjecture , given the lack of information . However , if Hornady have updated their 4-dof ballistics calculator , then it may be possible to compare and perhaps establish whether there has been improvements with regards to aerodynamic jump . That being said I suspect others will follow with a similar design , possibly a hollow point with an increased void , though there's a high possibility this has been previously explored .
Good luck with your R&D .

 

[Bavarianbrit]

RWS used to have a logo on the base on some bullets, is that why they are so expensive?

 

[NullMac]

Any statistical analysis to back up the voodoo?

 

[tim@tcs]

RWS used to have a logo on the base on some bullets, is that why they are so expensive?

Oddly enough all military 8mm Mauser bullets were marked in that way, most UK produced.303 projectiles were the same!
It’s usually mandated in military sub contracts for component suppliers. Even brass cases made for filling plants were marked internally as the head stamp was for the final assembler mark!

 

[AlexD]

Any statistical analysis to back up the voodoo?

Ballistics are fairly well understood.

Books such as Bryan Litz's set (Applied Ballistics for Long Range, Modern Advancements in Ballistics, Accuracy and Precision etc), have made Ballistic theory easily accessible.

There are hundreds of other papers on coning theory and aerodynamic jump, with lots of empirical data nicely analysed.

Lots of papers describing the basics, such as [1205.2071] A Coning Theory of Bullet Motions

On the analysis of your own data, tools such as the Blackburn Ballistics: https://blackburndefense.com/ group analyser tools make it easy to separate on factor from another.

This is just about using that information to produce a bullet tuned for windy conditions.

 

[User00044]

Have you any results to share ?

 

[tim@tcs]

My understanding of what you're trying to achieve is a bullet with weight bias to the rear , in an attempt to improve stability and reduce aerodynamic jump . I applaude you for the effort you're putting into this , but am unsure as to your end game .
Bullets with a rear weight bias already exist . The new Hornady ELD-VT , essentially they have taken a bullet of a heavier cup and core design and reduced the core . In doing so they have created a larger void behind the polymer tip effectively moving the weight bias back .
If the rear bias does have a positive effect on reducing the diameter of the conical movement during flight it may contribute to the higher BC figures claimed by Hornady . Although I've yet to see any hard figures . I would hazard a guess and say their ballistic guys are fully aware this .
I look forward to your results !

I’ve always believed the mass in the parallel sided portion of the projectile is the important part and that a certain proportion of mass to length was the guiding principle in stability!
Magic numbers aside 160 grain plus projectiles in 6.5 to 7mm fell into that category and the actual bullet shape at each end was a bonus opportunity to create a more streamlined version!
Experiments done between 1920 and 1939 into streamlined projectiles in .303 gave us the MkV111 loading for the Vickers MMG. The ammo was still available as a match load from Kynoch until 1960.
There obviously comes a point where the projectile length creates problems of its own regard to chambering but it’s a very interesting subject.

 

[scotch_egg]

Next year he will go one step further and create a donut bullet with a hole one end to the other

 

[AlexD]

Have you any results to share ?

Yes.

Moving the centre of gravity forwards opens up the group massively: making a pocket with a centre drill, 3mm deep in a 160gn bullet, so the centre of gravity is in the same place as where I think the aerodynamic centre is, causes the group to go from 1" to 8" at 200 yards. Not sure why, but that is what happens when tested using 7x.284 bullets, barrel is 1 in 7 twist, 28" long.

Moving the centre of gravity backwards using a tungsten ball pressed into a pocket formed using a centre drill causes the bullet to fly apart. I then tried dropping the balls in hot so it melts into a perfect form in the lead pocket formed by the counterbore, but a smidgen off-centre, and the weight becomes an imbalanced load on the bullet. I put the bullets into an ER32 collet when counterboring, so the counterbore is centred, but the press process may not be.

To try and keep the bullet in one piece, I have ordered some tungsten nail weights as they are a series of sharp cones that should be retained properly as they are longer and pouring in Woods metal first and keeping the nail weight hot as it is pressed in should fill the voids around the cones. They come from Aliexpress, so end of May before they arrive.

I don't have the option of making the parallel section longer because the bullet has to fit in a standard case, and SAAMI chambering, without extend into the neck.

Adding heavier material at the back of the bullet is the only variable I am playing with, to move the centre of gravity backwards. Will try again when the tungsten naii weights come in: I ordered various sizes. I am using a stick on target on a cardboard box in a field in testing these - not a range of course, as one can't guarantee where the bits go when they disintegrate.