NSWC testing on gas systems. CARBINE VS MID-LENGTH

[Coal Dragger]

Maybe the faster gun at 100M is achieving better stabilization of the round resulting in less oblong rotation of the bullet and better aerodynamic performance?

[MegademiC]

Maybe the faster gun at 100M is achieving better stabilization of the round resulting in less oblong rotation of the bullet and better aerodynamic performance?

I was thinking that could contribute to velocity as well. They are pretty much identical at muzzle, but the mid slows down less.

I dont get the cyclic rate at all . Can anyone elaborate on that? The concept makes sense, but the numbers dont- cyclic rate if 1rd per second?

[vicious_cb]

I was thinking that could contribute to velocity as well. They are pretty much identical at muzzle, but the mid slows down less.

I dont get the cyclic rate at all . Can anyone elaborate on that? The concept makes sense, but the numbers dont- cyclic rate if 1rd per second?

Maybe the faster gun at 100M is achieving better stabilization of the round resulting in less oblong rotation of the bullet and better aerodynamic performance?

That doesnt make sense either, same twist rate, same barrel length should have the same stability.

Whats wrong with the cyclic rate figures? They fit perfectly in line with lower port pressures=lower cyclic rate suppressed and unsuppressed.

[Serious Account]

A bit unrelated but.. does port erosion count as well when it comes to barrel lifespan?

CHF barrel combine with midlength gas could mean significant lifespan for the barrel and gasport.

[EzGoingKev]

Also, how do you get a velocity difference at 100m? i.e. how is that impacted if the muzzle velocities are similar? Gun X MV is 2900fps. Gun Y MV is 2900 fps. Yet Gun X is going faster at 100m? How the hell does that happen using the same ammo?

Thinking about how things work, the rifle with the carbine length gas system is going to unlock the bolt earlier than the mid-length. I am thinking that would yield an increase in muzzle velocity.

[vicious_cb]

Thinking about how things work, the rifle with the carbine length gas system is going to unlock the bolt earlier than the mid-length. I am thinking that would yield an increase in muzzle velocity.

Then you would see an increase in both muzzle velocity and 100 yard velocity.

[Mr. Goodtimes]

That accuracy standard is pretty crap .

It’s mostly due to the crap ammo they’re probably feeding the weapons.


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[npena84]

I'm thinking that CHF barrel, that mid length gas, and that EPR round. Sound like a nice little combo, especially if you can get Joe proof 1-6.

[MegademiC]

That doesnt make sense either, same twist rate, same barrel length should have the same stability.

Whats wrong with the cyclic rate figures? They fit perfectly in line with lower port pressures=lower cyclic rate suppressed and unsuppressed.

Edit- I read a 62 round cyclic rate, not 62 rpm less. I miss-read it.

[Coal Dragger]

That doesnt make sense either, same twist rate, same barrel length should have the same stability.

Whats wrong with the cyclic rate figures? They fit perfectly in line with lower port pressures=lower cyclic rate suppressed and unsuppressed.

Not necessarily. All things being equal stability should be the same, but some barrels are more accurate than others. Why is that? Might be something to do with the chamber, and lead being more concentric to the bore, allowing the bullet to enter the rifling lined up perfectly. Hammer forged barrels usually feature a chamber that is forged along with the rifling, everything is concentric.

There is a phenomenon where sometimes a bullet doesn’t “go to sleep” right away and will display some yaw on the rotational axis. It’s been noted mostly with very high velocity projectiles. I read an article once about a Weatherby long range rifle in .30-378 Wby that was nothing special at 100 yards, but the same gun with the same ammo shot the exact same size group at 300 yards that it did at 100 yards. It took awhile for the bullet to settle into a perfect spiral axis.

If the CHF barrels are that much more accurate in testing with the same ammo, it tells me that the CHF barrel is helping that projectile be more consistent in some way.