What is the maximum FPS of rifle rounds?

[44 AMP]

Every bullet built to expand is made to do so within a range of velocities. Since there is a lower limit, there must also be an upper. Drive an expanding bullet too fast and it will come apart.

If you want the highest speed possible, then a solid is needed. The rest is a matter of how much pressure you can put behind it.

back in the 90s I saw an article about someone using a .243 case, firing a .17 cal pellet (or maybe it was a 17gr pellet I don't recall anymore) what I do remember was they got 6000fps. But it wasn't a rifle, it was a bench mounted test fixture with something like a 6 foot barrel that fired it.

[B.L.E.]

The biggest problem in trying to achieve those hyper velocities is that the gunpowder, and thus the gasses that propel the bullet starts to outweigh the bullet. P.O. Ackley attempted to break the 5000 fps barrier with a wildcat cartridge he dubbed the .22 Eargesplitten Loudenboomer. He managed to reach 4600 fps with a 50 grain bullet propelled by 105 grains of powder. The powder outweighing the bullet by over 2 times.

It's like trying to make an electric car have a 1000 mile range by adding more batteries. You reach a point where the car is literally a battery on wheels and adding more batteries gives you a bigger battery on wheels, the extra weight of the additional batteries means it takes more energy to move the car and you reach an impasse.

One way to break new speed records would be to shoot an artillery shell that was itself a gun barrel that fires right after clearing the cannon's muzzle and adding the shell's velocity to the second projectile's velocity.

But what if we could invent a gunpowder that explodes into pure hydrogen instead of nitrogen, water vapor, and carbon dioxide? Meet the two stage light gas gun invented by NASA scientists to simulate meteor impacts in outer space.
In these guns, a rifle cartridge shoots a plastic piston down a smoothbore cylinder that contains compressed hydrogen gas. This compressed hydrogen than propels a light weight pellet down the bore of a gun and shoots a target that's in a vacuum chamber. Air is a bore obstruction when the projectile reaches 30,000 fps.

Here is an animation of how the device works.
https://www.youtube.com/watch?v=B4QGtVyIRHc

Some folks have also filled precharged pneumatic air rifles with compressed helium instead of air. It results in a significant velocity gain because the helium can accelerate to keep up with the pellet due to its low mass.

[hounddawg]

I had a Criterion .204 Ruger barrel on a Savage 10 that shot 32 gn Blitzkings at 4000 - 4250 on a good day. Good barrel life too, I pulled it when the avg 100 yard group size dropped from the .3's to the .6's with around 2500 - 3000 rounds. When it was humming you could put some RL10x behind a 39gn SBK and shoot 5 shot 1 hole groups all day long. It was like a laser to 200, shot ok at 300 but by 600 the groups looked like a shotgun pattern

[RC20]

This really should be restricted to rifled barrel.

120 MM Smoothbore can get 5600 FPS and I think the longer version goes faster still.

I do think its an interesting question as to when do you read speed in a rifle barrel that simply run into rotation or other issues that make it possible but you can't hi the broad side of a bran at 25 yards with.

[Picher]

I also bought a box of 30-06 Accelerators and wasn't impressed with accuracy, but the worst part was that they printed about 6" off where either other factory or handloads printed at 100 yards. I never shot any critters with them, but continued to use 125 grain Sierra varmint bullets in handloads with great success.

[Art Eatman]

Fun with the '06: Back in my early daze of handloading, my uncle gave me some 80-grain .32-20 bullets that he'd run through a .308 swager. I used 54 grains of 3031. This was before the days of home chronographs, but Phil Sharpe had listed a load with 80-grain pistol bullets at 3,900.

My load did terrible things to jackrabbits.

[Don Fischer]

Originally Posted by T. O'Heir

Like most things like that, it depends. There really isn't a set velocity after which any bullet will disintegrate though. I recall seeing a gun rag article about some guy trying to get to 5,000 FPS. Years ago and I don't remember anything except the guy trying it.
20 grain, V-Max, .17 Remington Start loads can go over 4,000 FPS. Max load of CFE223 runs close to 4,500 FPS.
How fast before destruction depends on velocity, rifling twist and bullet construction.

I think your talking about Jim Hutton, Hutton rifle Ranch. I read the same article.

[Don Fischer]

Originally Posted by Pathfinder45

What does it matter? What are you trying to achieve? Numbers for their own sake without an intended purpose?
The 220 Swift has been known to disintegrate bullets in mid-flight, that is, when bullets are constructed for much slower calibers like the 22 Hornet and then loaded in the Swift to much higher rotational speeds than the bullet was engineered for.

Hornady used to warn against shooting their super fragile, SX 22 cal bullet's in excess of 3500 fps, claimed they would blow up in flight. They were right. Friend and I tried it in his 22-250 and loaded to right at 3500 fps. Easy to tell when it exceeded 3500!