Watching this video here, an 18" inch Aero barrel had lower muzzle velocity than a 16" inch BCM barrel.  This was with 55gr Fiochi:
Aero 18"  2837.3 fps
BCM 16"  2851.1 fps

He got a similar result with a 62gr bullet:
Aero 18"  2807.3 fps
BCM 16"  2815.3 fps

With a 77gr smk the Aero was faster:
Aero 18"  2542.3 fps
BCM 16"  2518.9 fps

I would have thought that the barrel that is 2" inches longer would be much faster.

[youtube]_mAA0PLrNco?t=585[/youtube]


Any chance anyone has tested with Federal XM193?

It very much depends on the loading as different powders can make a huge difference in pressures and velocity.  That said, with the right load you can be within a pretty small FPS difference between the barrel lengths.  

https://rifleshooter.com/2015/12/223-remington-5-56mm-nato-barrel-length-and-velocity-26-inches-to-6-inches/

Inb4 Blain.

That Aero probably had some combination of manf tolerance that increases bore volume. Freebore length, leade angle, bore diameter, groove width and number...

Embedded for OP.

Probably because their rifling looks like a steel file.

Thanks.


I was wondering if there is some characteristic that makes them slower.  Like HighpowerRifleBrony said.

Some other articles with chrono tests that showed Aero rifles to have fairly slow muzzle velocities.

https://www.shootingtimes.com/editorial/aero-precision-ar-build/376725
Among the chrono tested ammo was Winchester Varmint-X 40gr at 3120 fps with a 16.1" inch barrel.
That ammo is advertised at 3600 fps.  (I would guess with a 20" inch or possibly 24" inch barrel.  A 16" inch barrel should not drop muzzle velocity by that much.)

These guys said they had disappointing velocities with a few ammo types:
https://theolddeerhunters.com/aero-precision-223-review/
Among the chrono tested ammo was Fiocche 223 40 gn V-max at 3250 fps with an 18" inch barrel.
Which has an advertised muzzle velocity of 3650 fps.

Both of those reductions in velocities seem fairly significant.

Barrels usually gain some velocity around the 100 to 150 round count.

A 5.56mm chamber will usually have a lower velocity than a .223 Wylde shooting identical ammo.

I wouldn't worry about it.

This.  Lots of variables at play.  The short version is some barrels are faster than others.

To be perfectly honest I've had nothing but bad experiences with Aero/BA barrels...

Couldn’t see the video til HP posted it.

The Aero is a 223 Wylde chamber with a 1/8 twist.

The BCM is a 5.56 chamber with a 1/7 twist.

It’s really interesting because this is the exact opposite result of what it should be on paper. Insert theories on tighter chamber, less friction from a slower twist, etc.

Even as bad as BA/Aero barrels can be, I don’t think there’s really that much variance from sloppiness possible for a barrel that can still print for shit on paper.