Military Guns and Ammunition

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

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New 5.8mm DBP191 ball and DVC12 AP round info and comparisons with 6 ARC and .22   Ammunition <20mm

Started 28/10/21 by Augmentcore; 1177 views.

From: roguetechie


That sounds quite interesting Stan.

Now if only we can get them to adopt an optimized high pressure bolt and extension design we've got something really worth doing!

Without the high pressure optimized bolt group you run into the issue that's already handicapping both these rounds, pressure and bolt thrust limitations.


From: nincomp


As others have noted, there has been great debate over the exact definition of GPC.  It was discussed a great deal on this site a decade or so ago.  From what I recall, some wanted the projectile to be effective out to 1000m.  Over time, more argued for shorter differences, down to as little as 600m.  Early on, a number of us here figured that the 6.5 Grendel was not quite powerful enough, if that gives you any idea.  

The adoption of lead-free bullets had a major impact on meeting earlier GPC retained energy goals.  The less dense materials being considered for a general-use bullet dropped the BC to where meeting even 800m goals began to require so much propellant that the cartridge edged closer and closer to the size and weight of 7.62x51.   In fact, it can be argued that even the 7.62x51 with the current M80A1 projectile no longer meets the energy-at-range range goals of some GPC's proposed fifteen years ago.

Both the 6mm ARC and the .224 Valkyrie are hampered by the fact that they were designed to fit into the AR15 platform (without strengthening the bolt and barrel extension or widening the magazine).  This meant that the chamber pressures were reduced when compared to the 5.56x45.  Feeding the larger diameter cartridges through a magazine well designed for 5.56x45 is not optimum.  Note that when LWRCI developed the six8 carbine for the 6.8 SPC, they used a wider magazine.  Any new military cartridge should have its own platform to allow optimization.

  • Edited 29 October 2021 19:05  by  nincomp

From: Augmentcore


Although the high L/D ratio bullet and high initial velocity can effectively improve the long-distance ballistic performance and make .243 or .260 level cartridges to reach .300 Magnum level like 6 Creedmoor made by Hornady or 6XC made by David Tubb, the barrel burning caused by it is a more serious problem, and this is totally different from long range single-shot or benchrest shooting wildcat bullets that folk shooting masters need to consider in America when they are trying to discuss 6.8 NGSW series whose design concept is based on 6.5 Creedmoor as an option of GPC cartridges( Don't forget the origin of 6.5 Creedmoor is to match the huge requirement of bolt-action precision shooting medium caliber rifle) and hardly of the previous discussions had considered this aspect. It may cause a serious decrease in the life of the barrel and accelerate the loss of the barrel and the frequency of maintenance. Although this is not annoying in a civilian competition where you can shoot leisurely, it is likely to be fatal on a battlefield where every second counts.

So in order to avoid the barrel burning in automatic mode, a meaningful diameter is .25 cal (only in my opinion). .260 cal is too big to get ideal ballistic coefficient like 6.5 Grendel (TOO slow), while .243 cal is too small to make multi-purpose bullets such as dim-tracer. What do you think?


From: EmericD


Augmentcore said:

So in order to avoid the barrel burning in automatic mode, a meaningful diameter is .25 cal (only in my opinion). .260 cal is too big to get ideal ballistic coefficient like 6.5 Grendel (TOO slow), while .243 cal is too small to make multi-purpose bullets such as dim-tracer. What do you think?

"Optimum" bullet diameter is just a by-product of the amount of the muzzle energy you want to achieve from barrel length with an expansion ratio around 8-9.

The original idea was to duplicate the retained energy of the 7.62 x 51 mm with a smaller / lighter round, it was already demonstrated that you could achieve this goal at 600 m with a .264" bullet and ~2500 J of muzzle energy, but a .236" bullet and slightly less muzzle energy will be OK, or any diameter between (.243" and .257").

The .243" seems to be sufficient for long-range tracers and can be used in "micro action", while the .264" will eat too much internal space and will probably need a longer action.


From: smg762


Going back to the 5.8mm ammo, task and purpous has a new video on the chinese bullpup ...just uploaded right now


From: Augmentcore


But the problem is that bullpup rifles like QBZ95 are now a marginalized part of China. The current new rifle like QBZ191 is just an imitation of the AR series and HK416, even the buttstock can only be retractable but not foldable (because the built-in reintroduction pipe has been almost reached the bottom plate of the buttstock like those old M16/M16A1), I think this can already explain the problem. So the problem of insufficient barrel length (14.5 in, the same as M4A1) will not only be faced by the American AR rifle, but the new Chinese rifle will also be troubled by this problem.


From: stancrist


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