fluted chamber...

Pierre

a fluted chamber is not recommended when shooting subsonic ammo, they say. Question: what is a fluted chamber ?? The s/a rifles are Colt AR in .223 and Sig 550 also in .223.
jack.schneider@caramail.com

n/a

Could it be they are talking about a revolver? as the cylinders are fluted on most, but some that fire the extra high power shells, are not, Fluting makes the round chamber a bit thinner than not fluting

LR

Tailgunner1954

There were some military weapons that had grooves (flutes) cut into the chambers to ease extraction, by using the flutes to channel gas back around the case forcing it away from the chamber wall. Not very common in the civilian market. If you see fired brass with ridges running back from the mouth thru the shoulder area you'll know what happening.
I suspect that this is what your ammo manfacture is refering to.

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Some guys like a mag full of lead, I still prefer one round to the head.

cpermd

HK 91
cpermd

JustC

ya beat me to it cpermd.

A great rifle with a junk scope,....is junk.

spclark

...and the Grendel P-30.

Had one for a few months awhile back - shot o.k. for a mostly plastic curiosity but the .22 Magnum is wasted with a barrel that short. Shoot 20 or 30 rounds, then have to strip & clean the chamber (paying special attention to those grooves) to get it to extract clean again.

Pierre

quote:
Could it be they are talking about a revolver? as the cylinders are fluted on most, but some that fire the extra high power shells, are not, Fluting makes the round chamber a bit thinner than not fluting

LR


Thanks, the .223 (5.56 NATO) ammo is for semi-auto rifles. I think that fluting a chamber has something to do with the operating gases to eject the empty casing, yet I am still trying to find this out, since I am not too crazy about wasting a 3K rifle. Thanks.

Pierre

quote:
Could it be they are talking about a revolver? as the cylinders are fluted on most, but some that fire the extra high power shells, are not, Fluting makes the round chamber a bit thinner than not fluting

LR


Thanks, the .223 (5.56 NATO) ammo is for semi-auto rifles. I think that fluting a chamber has something to do with the operating gases to eject the empty casing, yet I am still trying to find this out, since I am not too crazy about wasting a 3K rifle. Thanks.

Pierre

This ammo (.223 - 5.56 NATO) is for semi-auto rifles, assault type.
Tailgunner 1954, I had someting like your answer in mind but I am still looking for the perfect answer - Id hate to waste a $ 3K marvel...
Pete
pierre13669@yahoo.com

LIKTOSHOOT

Not sure what your looking for in the "perfect" answer. The AR styled rifles do not use a fluted chamber and it would be pretty useless on a gas operated rifle to start with. Fluted chambers allow a small amount of blowback to unseat the case mouth (float) for extraction. The HK series in .308 with the delayed roller lock system allow a slight delay in the rearward bolt movement as the case is upset in the chamber, then on the extraction stroke, it pulls the case back. This allows for continued firing over a dirty chamber for reliability, not much for reloading as the case`s are butcherd pretty good......easy rifle to track. Spent brass is a dead giveaway. Best LTS

v35

I believe the fluting is to add drag between case and chamber to delay opening and reduce the load on the locking system. Sounds like a patch job on a bad action system. In the past,someone named Kimball marketed a straight blowback 30 Carbine pistol on a HiStandard frame, using this principal, that was dangerous.
All things considered including wrecking the case and the case signature,I wouldn't buy one.

kimberkid

The HK-93 (.223) also uses a fluted chamber. Because of the delayed blow-back design the flutes are necessary to equalize the pressure between the case and the chamber wall, otherwise the case will momentarly seize the chamber wall and not extract/eject. If there is a hint of lube on the case it will extract/eject but blows out (or breaks) the shoulder of the case ... resembles a sevear headspace problem.

I learned this the hardway when I built my G3 Tactical Clone ... ended up sending it to Murray Urbach in Garland Texas to flute the chamber using EDM process ... haven't had a problem since.

I think it would not be reccomended as the bleed-off at the flutes would result in even lower pressures and may not function if used in a semi-auto like the HK-93.

=================================
The only bad thing about choosing a Kimber ...
... there are so darn many models to choose from!
kimberkid@gunbroker.zzn.com

Edited by - kimberkid on 06/07/2002 21:08:26

Tailgunner1954

Pierre
Look into the chamber with a mirror and light, if it's fluted you will see it. If that's to dificult fire a full power round in it and eyeball the spent brass if it looks like a new round (smooth), but minus the bullet, the chamber is not fluted. Neither of these methods will dammage your weapon.

V35
The weapon your thinking of had groves AROUND the chamber, The flutes we are discussing run LENGTHWISE at the front of the chamber.

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Some guys like a mag full of lead, I still prefer one round to the head.

v35

Tailgunner, I think the Kimball and HK involve essentially the same principle. Circumferential or longitudinal flutes both add surface area to the case which when multiplied by the pressure increases frictional forces in the chamber over an unaltered chamber. The kimball also added mechanical interference but the reasoning is the same; to delay breech opening and compensate for a failure of the action timing. Experience cited above demonstrates that unfluted or oiled chambers affect those frictional forces and separates cases because they are being extracted too early before chamber pressure starts to subside and the brass relaxes. It would be interesting to compare height of shoulder and o.a.l. of fired and unfired brass.