POF fluted chamber

[Canadian Bushman]

My buddy at work was showing me this fluted chamber neck design that POF is using in their new AR platform. Apparently it was an old idea used by HK and POF is putting a new spin on it and giving it a go.

Maybe im too closed minded, or just plain traditional but i do not like the sound of this idea. What do you guys think?

https://www.pof-usa.com/esquared.html

 

[WildRose]

My buddy at work was showing me this fluted chamber neck design that POF is using in their new AR platform. Apparently it was an old idea used by HK and POF is putting a new spin on it and giving it a go.

Maybe im too closed minded, or just plain traditional but i do not like the sound of this idea. What do you guys think?

https://www.pof-usa.com/esquared.html

In an AR platform rifle, especially one you will not reload for I can see it being a great idea.

I cannot see how it would have any positive effect on accuracy and potentially see it could hurt it.

It seems like a really good way to screw up your brass for reloading.

Most of the time if you are having a problem with an AR it's related to extraction, or debris in the chamber preventing proper cycling so for reliability in a fight, it makes sense. I can't see it being a benefit otherwise.

 

[Canadian Bushman]

I think you make a solid point in relation to ar's and extraction problems, and i didnt consider how that would relate to a combat situation. In that scenario it really starts to seem like a good idea.

I was really wondering how you would clean those tiny grooves and what would happen if they were not cleaned properly and carbon was allowed to build up. Could it have the reverse effect and make a shell harder to extract?

 

[Mike 338]

Fluted Chamber is regarded as a plus for a battle rifle.

 

[WildRose]

I think you make a solid point in relation to ar's and extraction problems, and i didnt consider how that would relate to a combat situation. In that scenario it really starts to seem like a good idea.

I was really wondering how you would clean those tiny grooves and what would happen if they were not cleaned properly and carbon was allowed to build up. Could it have the reverse effect and make a shell harder to extract?

No more of a problem than a dirty chamber. A sharp dental pick would easily remove carbon or debris.

With any military rifle one of the critical elements is how well they can perform when muddy, sandy, wet, dusty etc which is why you find ways to create channels and grooves for crap to move to in order to keep it from gumming up or clogging the operating system.

This is actually where the idea for fluted bolts came from. Of course a fluted bolt is also less likely to freeze and stick to the point you can't operate the action in sub freezing wet weather..

 

[Canadian Bushman]

I guess there is no reason to dislike this chamber idea. Except from a reloading standpoint.

 

[J E Custom]

I would be worried about gas cutting. We try hard to get the brass neck to seal the chamber as quick as possible so any gas cutting is minimized. I am sure that everyone has seen gas cutting
on bolt faces from loose primer pockets or hot loads.

There may be some advantages for the military because they don't reload and if a barrel goes bad they simply replace it.

I don't think "I" want to aid this process. So I will just have to pass on this.

Just My opinion

J E CUSTOM

 

[Canadian Bushman]

We try hard to get the brass neck to seal the chamber as quick as possible so any gas cutting is minimized.

Is this for accuracy?

 

[J E Custom]

Is this for accuracy?

It protects the chamber and improves SDs. (That is why some guys like the tight necks that also center the case in the chamber better.

If it seals Immediately It also minimizes carbon build up in the neck and chamber.

If a case neck splits during firing Sometimes it will cause gas cutting and damage the chamber.

The worst case I have seen was when the wrong cartridge was fired in a rifle and the entire case
split blowing the primer and cutting the chamber from front to back. It was saved buy setting the chamber back enough to clean it up.

I have never owned one of these type of chambers and have no experience with them, but It is just
not something that I will try until lots of experienced people convince me that It is better.

J E CUSTOM

 

[Canadian Bushman]

Sounds like solid reasoning to me.

 

[Kennibear]

Fluted chambers started being used when the first self-loaders were being adopted by the world's militaries. The early designs lacked primary extraction and the trapped gas between the case and chamber wall helped the case release from the chamber and the anemic extraction of early designs became more reliable. Dirt in the chamber screws it up no matter what. Generous chamber size helps with dirt too.

H&K used fluting on their roller locked design because it lacks primary extraction. It is momentum driven and the initial impulse given to the bolt carrier is all she wrote. Gas designs have a longer impulse cycle and have residual force being applied when the primary extraction is going on.

Our requirements are quite different and a tight fitting chamber is the end all of it. But there is no doubt that the roller locked self- loader pioneered by the MG-42 is a proven design in implements of war.

KB

 

[Canadian Bushman]

So youre saying fluted chambers are not as much help to todays semi automatic designs as the days of old?

 

[Kennibear]

Stoner did not need a fluted chamber for the AR. Kalashnikov did not use a fluted chamber in the AK.The FN-FAL has a normal chamber. All gas guns. Timing counts. Gas guns have an unlocking/ extraction start delayed by the gas tap off requiring time to set the action in motion. So the chamber pressure drops and the case relax away from the chamber wall.

Recoil/inertia based actions begin unlocking/extraction as soon as the recoil imparts motion to the gun. The chamber pressure is reduced but far from zero. With most brass (338 Lapua is an exception) containing maybe 5Kpsi anything higher is jamming the case against the wall.

That being said the needs of tactical arms are: reliability, ruggedness, simplicity, and durability. Roller locked actions deliver that set of qualities very well. But they require a fluted chamber for reliable extraction. The fluted chamber costs more to manufacture but it is made up on the simplicity of the rest of the mechanism. They are cleaner opperating as gas doesn't bath the action every shot.

Middle son has AR's, AK and CETME autos. He loves his CETME.

Nuff' said!

KB

 

[Canadian Bushman]

I think i understand now.