Fluted Chambers in the AR15

[ROUGH]

The HK 50 series of weapons use a fluted chamber to aid in the extraction of
the the shell, because of the delayed roller blowback system (very dirty) blows
gas back in the flutes and helps to release the shell from the chamber.

I am wondering in your opinion, would a fluted chamber in the AR15 series of
weapons increase the extraction reliability of the weapon. It would obviously
get more dirty from some gas flowing into the flutes, but if it helps to release
the bond between the brass and chamber wall earlier, then it would in theory
increase the extraction reliability of the system.

Due to the less surface area holding onto the brass, this in theory would also
have less drag on the shell, tension on the case rim and extractor notch,
lessening the ware and tear in the extraction parts.

I also think the flutes would give large debris a place to go, keeping the contact surfaces free from blockage.

This is just something I was thinking about and thought I would pose the
question to people with more experience in these technical matters.

[Chief1942]

Would be interested in seeing the ejected shell casings from a fluted chamber. I suspect that the brass would reflect the expansion space provided by the flutes and therefore be unusable for reloading. Just a thought.


Semper Fi!

[STLRN]

Would be interested in seeing the ejected shell casings from a fluted chamber. I suspect that the brass would reflect the expansion space provided by the flutes and therefore be unusable for reloading. Just a thought.


Semper Fi!

There are longitudinal flutes added to the brass, however I have been able to reload them. I don't know how many reloads they could go, but I have had success using the reloads in both my H&K and FN.

[RyanB]

I have heard of people reloading brass from HKs....once. After that it's trashed. Also, fluted chambers tend to lower velocity.

If it ain't broke, don't fix it.

[cohiba]

I have heard of people reloading brass from HKs....once. After that it's trashed. Also, fluted chambers tend to lower velocity.

If it ain't broke, don't fix it.

The brass is reloadable. Its ugly but its reloadable. The flutes are powder deposits that come right off. But the REAL problem as any HK guy can tell you is FINDING the brass. HK91s and 93s throw their brass into a "galaxy far, far away".

[RyanB]

I once made the mistake of watching someone shoot my SAR-8 from 5 or so feet right of the ejection port. A piece of brass to the sternum cured that practice forever!

[Nitrox]

Adding flutes to an AR chamber would be an exercises in futility. HK uses (used) them because they had no gas system but since the AR is direct impingement there is no need. The AR gas system delays unlocking long enough for chamber pressure to drop and the case to shrink. The HK on the other hand has to have flutes because it is essentially a direct blow back with small detents to slow the bolt. The flutes are just an added measure to keep the case rim from being torn off by reducing case wall adhesion in the chamber.

I use communist conscript steel cased wolf ammo in my communist conscript HK rifles. Shit ammo in shit rifles I always say.