US Army Developing New Designs for Hypervelocity Firearms

The US Army revealed plans to develop a new approach to bolt and chamber design that would allow cartridges to be loaded to insane pressures (up to 100ksi compared to today’s 62ksi for 5.56).

Among their goals is hypervelocity for extended range lethality from standard sized weapons, and full-sized rifle velocities with firearms that are half the weight, half the length, and hold more ammunition than the Army’s M4 carbine.

“The goal is to get rifle-like velocities out of a very small weapon that is high capacity, that’s either adaptable for room-clearing or confined spaces,”

The muzzle velocity was over 2,900 feet per second, outperforming similar short barreled weapons like the FN P90, which rates at 2,350 feet per second at the muzzle.

(T)he U.S. Army’s new 24-inch prototype barrel produced muzzle velocities of 4,600 to 5,750 feet per second.

This is all centered around a new bolt lockup design that uses a screw (hasn’t this been common on artillery pieces for over a century? Why is this just now being tried in small arms?) and a collet surrounding the brass case to keep it from expanding against the chamber wall so tightly that extraction becomes impossible. They’re also playing around with tapered barrels which has me curious about what they’ve done to prevent barrel wear with these absurd velocities and the obvious increase in stress and friction associated with tapered bore designs. The drawbacks in terms of durability are obvious as many of these ideas have been tried in the past only to be abandoned as the best materials available still were not enough to overcome the increased wear associated with hypervelocity speeds and pressures. Maybe they’ve made some sort of materials science breakthrough in terms of barrel material? A ceramic coating perhaps? It’s still a very neat development that could result in a huge leap in firearm performance if it pays off.

(the story is a few months old but it’s news to me)

That’s a hell of a boost.

If I’m reading this right the ammo for such a design would be conventional except for the propellant.

Add something like a tungsten core jacketed round and armor would be much less effective.

I have fired sabot rounds in my 03 Springfield ( about 4,000 fps ). Light rounds & very fast, but not for windy days; as they can wander. Regular 30 06 ball rounds on windy days.

I wonder if their new design will be yet another M4 variant…because we don’t already have enough of those floating around :rofl:

Myself, I like elegant firearms. 03 Springfield with the Kahles competition telescopic sight. I’m a sandbag shooter. Actually the bag is filled with washed aquarium gravel; since it won’t leak out & possibly compromise the action of the rifle. Only takes a tiny bit of sand in the wrong place. The Germans found out about this when they used the Luger in the desert. Fastest action of any semiauto pistol; but not if it’s exposed to sand.


Firearms development seems to have waned since its heydays in the 19th century and early 20th century. Mostly mass production techniques and chemical engineering of propellants are all that we see. Instead of leading technology in the 19th century, firearms are based on advancements from other technologies by the 20th century. Now in the 21st-century firearms are almost steampunk accessories for “muh sekkin uhmuhndmuhnt” tacti-cool losers.

An AP round traveling at >4,000 f/s would make all body armor absolutely worthless. I cannot think of a single body plate on this earth that could ever stop a bullet going this fast.

Armor piercing WW2 surplus ( 30 06 ) was available by the millions; but most people bought it for the brass to reload, since the primers were super hot & corrosive. Fulminated mercury. One thing about it, never ever ( well extremely rare ) a misfire.