autogun

Military Guns and Ammunition

Hosted by autogun

This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

  • 3213
    MEMBERS
  • 182477
    MESSAGES
  • 3
    POSTS TODAY

Discussions

tubular bullets   General Military Discussion

Started 7-Jan by smg762; 2507 views.
smg762

From: smg762

9-Jan

We already know the increased hit probability you get from sabot projos. 

My point was he was suggesting impressive core accuracy- MOA or under.  

This conflicts with other sources which said it could be up to 33% less accurate than normal 762. 

It also maybe suggests that bullets,  not flechettes,  are the way to go with sabots.  

renatohm

From: renatohm

9-Jan

Under some circumstances, yes, APDS / SLAP works better than APFSDS, in others it's the opposite.

Things must also be weighed regarding accuracy and costs - 33% worse accuracy may be worth it in some roles but not in others.

Last but not least, this debate belongs to another thread - this one is about tubular bullets, not saboted ones.

JPeelen

From: JPeelen

9-Jan

When Hebler and Krnka experimented with tubular projectiles about 130 years ago, the goal was to dramatically reduce air drag. It was believed, the inner cross section would be passed by the air undisturbed. 

They could not know the peculiarities of supersonic aerodynamics and the creation of shock waves inside the tube by its "mouth". The plan works only at very high Mach numbers. If velocity drops beyond a critical value (dependent on tube diameter and length), the tube flow becomes choked. Therefore, modern existing tubular bullets (like the one shown by Tony, or the defunct Rheinmetall LKL-projectile) are used for achieving an additional brake effect. They are training projectiles for shorter ranges, not enhanced ranges. 

Hopefully someone fit in aerodynamics on this forum can tell us the approximate Mach number at which a 5.56 mm tubular projectile would work as intended. I would not be surprised if it were useful only while it flies well above Mach 3.          

  • Edited 09 January 2021 14:41  by  JPeelen
smg762

From: smg762

9-Jan

Vaguely returning back to the original subject,  could you have a bullet with striations running longitudally along its length. (From tail to nose)

To get a visual idea,  Google bullet striations and look at the 9mm rounds.  Imagine that but Much deeper. 

They could either be straight,  or angled which would add spin to bullet. 

Then you have a wad behind the bullet. 

The idea is that it gives the drag profile of a tiny caliber bullet,  but the overall bore size is closer to. 22 - thus it gives no barrel wear. 

Also,  someone has a patent for a disk shaped bullet

https://patents.google.com/patent/US20140150319A1/en

Regarding jpeelens thoughts on the tank training ammo being short ranged,   a rifles tubular ammo would only need be stable at 600m

  • Edited 09 January 2021 15:46  by  smg762
renatohm

From: renatohm

9-Jan

Aerodynamics is such a fascinating subject!

If useful only above a high Mach number, tubular projos could find a new life through rail guns, whose velocities are usually very high.

smg762

From: smg762

9-Jan

Does anyone have any thoughts on my striations idea?  Assuming it's viable I think it's far superior to tubular/sabots or anything else. 

Remember the idea is to emulate the drag profile of a microcaliber,  and yet avoid the barrel wear problems

Red7272

From: Red7272

9-Jan

smg762 said:

This conflicts with other sources which said it could be up to 33% less accurate than normal 762. 

Well yeah, but in still air 7.62x51 can shoot .5 MOA at 1000 metres. The whole point to sabot is to improve accuracy in less permissible environments. 

Red7272

From: Red7272

9-Jan

smg762 said:

Remember the idea is to emulate the drag profile of a microcaliber,  and yet avoid the barrel wear problems

What barrel wear? That is unrelated to calibre. 

smg762

From: smg762

9-Jan

Well as my posts often show I'm a proponent of calibers around. 17 or so.  With very heavy-for-caliber bullets,  you get extreme range yet very low recoil and weight. 

Obviously the drawback is major barrel wear.  So the striation idea was to emulate a. 17,  but with a bore size closer to. 19 or. 22

nincomp

From: nincomp

9-Jan

Do you intend for the striations to impart the spin rather than rifling?

TOP