Pop Quiz!

[Hocktl]

I had the honor of shooting with a couple shooting instructors from the police academy a couple weeks ago, one who is my neighbor. Anyway one was an advid reloader and we were discussing reloading the 308 since we were shooting the SCAR-H and he said he had a metric butt ton of military brass and offered some up. Thanks Bob! I gladly accepted and a couple days later he offered up a gallon zip lock bag full of mostly Lake city and Western brass.

There were 14 LC Match headmarked pieces in the bag. They all had ribs or ridges running vertically with the case neck. Only the match marked brass had it and it really looked like it belonged there.

11062_lc_match_1.jpg (3.09 KiB) Viewed 2252 times

Now I'm pretty sure I have seen this before on brass but don't recall when or where and I was wondering why the match grade would have it and what it was for. I do know I've not seen it often and mysteries bug me.

There is alot of talk that it is how they mark brass to identify it as competition brass. I don't buy it. I have found where there have been markings put on match ammo for that reason but it is a cannelure marking around the base that is horizontal to the case vice verticle like these.

Took some research but I finally solved the mystery. I will certainly reveal what I've found but first was wondering if anybody is familiar with it.

[jdonovan]

There were 14 LC Match headmarked pieces in the bag. They all had ribs or ridges running vertically with the case neck. Only the match marked brass had it and it really looked like it belonged there.

11062_lc_match_1.jpg

Looks to me a lot like the brass came from a H&K with a fluted chamber.

[jdonovan]

after looking more closely, H&K only puts flutes on the body, not the neck, and shoulder, so I'll retract that theory on H&K.

This brass was loaded with the Sierra 168 gr HP bullet for CONUS match use. The knurling was used because the Hague Convention prohibits HP ammo in combat, and it was felt the knurling would alert the shooter that this was not suitable for combat use.

[Hocktl]

after looking more closely, H&K only puts flutes on the body, not the neck, and shoulder, so I'll retract that theory on H&K.

This brass was loaded with the Sierra 168 gr HP bullet for CONUS match use. The knurling was used because the Hague Convention prohibits HP ammo in combat, and it was felt the knurling would alert the shooter that this was not suitable for combat use.

Really? You don't think the flutes would impact accuracy on match grade ammo? Your first answer was correctin that it is not made that way but gets the markings as a result of firing from a rifle that has a fluted chamber.

Seems some, mostly foreign rifles that use NATO rounds have fluted chambers that allows gas blow by to aid in extraction. The brass expands when fired and puts these markings on the rounds. Pretty much ruins it for reloading.

Learn something new every day.

"Many military rifles such as several H&K variants, the FAMAS, Cetme, etc. all used a delayed blowback system for functioning. Blowback is a system of operation for self-loading firearms that uses the power from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the rifle powder to cycle the rifle action. It works especially well with the delayed roller block types of actions like the H&K and the Cetme. The Valmet also uses fluted chambers.

Most of the available 22 LR semi-autos use the simple straight blowback system without the need for chamber flutes. With higher chamber pressures, delayed blow back is needed, and there are several ways to do it. Fluted chambers serves as an assist for these higher pressure delayed blow back systems.

In a nutshell, as has been stated, ease of extraction of a cartridge case is the whole idea behind fluted chambers.

The chamber flutes are rounded to a degree so as not to sharply indent, or crease, the case. But the cases suffer the brunt of fluted chambers, coming out looking sooty, fluted, dented, gouged, scratched, and showing about any other "owie" you could think to put on a piece of rifle brass. Not something reloaders would like.

When early models of the M16 were experiencing jamming problems, one answer looked at was to flute the chamber to allow blowby gas to aid in extraction. As we all know it was not an answer used to solve the problems with the early rifles, but it was an option pursued."

Bottom line is these go inthe recycle bin.

[jrswanson1]

My CETME does that. And it's not an HK variant, thank you, as it predates the HK and the design was licensed by HK since FN said "No effin way" to the Krauts for their FN.

[Hocktl]

Jim, You'll note in the qouted response I made it mentions CETME as one of many that makes marks like this from a fluted chamber.

The point of the post was two fold. First is to kill the urban legend that they are made that way intentionally to denote competition brass and second that once marked with it, it is IMO trash for reloading.

[jrswanson1]

Jim, You'll note in the qouted response I made it mentions CETME as one of many that makes marks like this from a fluted chamber.

The point of the post was two fold. First is to kill the urban legend that they are made that way intentionally to denote competition brass and second that once marked with it, it is IMO trash for reloading.

Your quote read "Many military rifles such as several H&K variants, the FAMAS, Cetme, etc" I get a little worked up about this for less than obvious reasons. Yes, the brass is trash after firing from a fluted chamber. At least mine functions well with steel cased ammunition, although the bullet hits 6" to the left at 50 yards with Tulammo Standard NATO 7.62 ammo is dead on, though.

[Tweaker]

I have used these fluted brass pieces. I segregate them (cause I be waissis, as is well known) and use them for plinking ammo that I may do mag dumps in.

Mag dumps in a Kel Tec RFB at near full auto rates ---------> FUN!