Federal Peak Alloy 5.56

[Schmo]

The biggest thing I'd be watching out for is gas port pressure. If that pressure peaks too close to the gas port you can get ripped case heads, broken extractors, and excessive velocities on the moving parts, beating things up internally more. But if their powder spikes its pressure early and the pressure drops enough by the time the bullet passes the gas port, it'll be less of a concern.

It’s possible they’ll do it through powder selection, but also, regulate port size or go to adjustable gas blocks. I’m moving to adjustable gas blocks anyway for dialing in hand loads. I agree with Form. Don’t let Joe average determine where technology leads. If he’s ignorant and tears something up, that’s on him.

 

[JF_Idaho]

 

[djauofd]

I did go on Reddit and a similar discussion which involved the Alloy 5.56 am. Girsiele corporate account was answered some equations . I posed a question about thrust and recoil. I’ll let you know if the address an answer.


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[khuber84]

So listening to the shoot to hunt podcast Avery was talking to some the manufacturers testing the 7mm backcountry also in peak alloy. They reported that primers were protruding from pocket after firing. Not flattened from the very high pressure. This leads me to a thought. The steel case is gripping the chamber very well. Preventing rearward movement of the case during ignition, so much that the primers are able to move outward filling the headspace gap between bolt face and case head. This extra chamber grip may indeed be something that reduces bolt thrust.

 

[djauofd]

I’m thinking this is probably the case. No pun intended. If so, it would explain the thrust and pressure issue. However, as a consequence I think there will be a real possibility of chambering erosion as this thrust would be induced on the inside wall of the chambering.

If the case shrinks immediately as pressures drops, I would think it would be insignificant. This may be the case using higher speed powders, this would cause the initial higher pressure, but bleed off very quickly because all the propellant is being burned in the case and not being burned down the bore, which is basically how slower propellants achieve higher velocities while not increasing net pressure, as with say Alliant’s Reloder 17.

This would explain how the Peak Alloy 5.56 cases are able to function in a stock AR15 action. Of course my concern would be blown and pieced primers. Not much of an issue in a bolt gun, but problematic in a semi auto gas gun. As happened to me once in an AR10 the blown primer was bounced back into the chamber and as the next round went into battery the primer jammed the live round in place. Took a minute to get it out, had to disassemble the rifle back at my loading bench.


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[petespistol]

This article answered some of the questions brought up in this thread.

An Official Journal Of The NRA | Ammo: Making a Federal Case

Federal uses new technology to push the envelope on pressure and velocity.

www.shootingillustrated.com

"If you’re not a hunter, why should you care about the 7 mm Backcountry and this new technology? There are several reasons. For example, while evaluating the new 7 mm Backcountry cartridge, I also shot some 5.56 NATO ammunition loaded in Peak Alloy steel cases. Mixed in a magazine with standard 5.56 NATO ammunition loaded with the same bullet, I could not tell any difference. Federal techs said the hotter-loaded Peak Alloy cases generated a bit more recoil, but for me it was unnoticeable. However, the chronograph could certainly tell the difference. The 5.56 NATO ammo loaded in the Peak Alloy cartridge cases delivered velocities about 300 fps faster. That’s groundbreaking. And since SAAMI does not list standards for the 5.56 NATO, if Federal were to offer 5.56 NATO ammunition loaded in Peak Alloy cases, it could potentially render every other AR-15-compatible, .22-caliber cartridge obsolete."

 

[ArgentJ]

Any news on this front since early this year?

 

[djauofd]

Since this time I got Shell shock 223 cases. Out of a 20” barrel I’m getting real close to 3,200 fps. I get 3,050 fps with 75 gr HPBT’s , all loaded magazine length.

I also tried some loads with 88 gr ELD M bullets. I single loaded them 2.495 COL. I got 2,920 fps and they stabilized in my 1-8 twist barrel. The load would be transonic (1,234 fps) at 1,200 yds at sea level. You could have a single load bandoleer , you instantly have a 1,200 yd sniper rifles.

Pretty amazing. I did several cycles of reloads , that shell shock says should not be done . Can be done but you have to be careful and stick any cases that stretch at the point where the base and body join. Some other stuff like no full length sizing and only using a neck sizing die. But in each cycle the attrition rate is 25% to 30% so it’s not worth it . But performance wise it is crazy out of an AR15 223 chambering platform.

No need to replace M4’s or MK 12’s. . This case makes them relevant in a big way.


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[ZAK13]

Did the vid mention a beefier AR to handle the increased pressure?

My understanding is that the case itself handles the pressure, not the rifle chamber. The alloy Federal uses doesn’t expand like a brass case does when fired.

 

[djauofd]

The steel NA3 case does expand , the case head not. The case returns to it original shape almost instantaneously. So it expands to chamber wall and locks on them , then it springs back very quickly as pressure releases. The case hugs the walls and the case head only moves minimally , not until pressure releases so there is no significant bolt thrust issues.

The key is it quickly snaps back to close to its original size even while under lower residual pressures. say 10,000 psi. Brass does no spring back and it’s tight grip on the chamber walls is extended as the brass remain expanded under lower pressure . So say it remains stuck in chamber to 2,000 psi . This is where you get the smiles ( smears) on the brass heads.

This is why delaying the BCG from moving by using heavier buffers , springs and adjustable gas blocks allows you to shoot hotter loads. It delay the movement of the BCG just enough to allow chamber pressures to reduce to the point where extraction is not trying to pull out a round hung on the chamber walls.

I do this to all my target AR’s where I know I am going to push warm loads. The NAS3 cases mitigate or eliminate this requirement all together which is why you can use all existing hardware and still have a very measurable difference in overall performance. The pressure is managed mechanically by the case, leaving all the reciprocation hardware the same.
My understanding is that case are made to perform like this up to 100,000 psi.

Got to love the science, and the military armourers are happy as well.


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[RWT]

Any updates on a RTS date?

 

[ArgentJ]

Since this time I got Shell shock 223 cases. Out of a 20” barrel I’m getting real close to 3,200 fps. I get 3,050 fps with 75 gr HPBT’s , all loaded magazine length.

I also tried some loads with 88 gr ELD M bullets. I single loaded them 2.495 COL. I got 2,920 fps and they stabilized in my 1-8 twist barrel. The load would be transonic (1,234 fps) at 1,200 yds at sea level. You could have a single load bandoleer , you instantly have a 1,200 yd sniper rifles.

Pretty amazing. I did several cycles of reloads , that shell shock says should not be done . Can be done but you have to be careful and stick any cases that stretch at the point where the base and body join. Some other stuff like no full length sizing and only using a neck sizing die. But in each cycle the attrition rate is 25% to 30% so it’s not worth it . But performance wise it is crazy out of an AR15 223 chambering platform.

No need to replace M4’s or MK 12’s. . This case makes them relevant in a big way.


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Did you shoot them at distance as well? Are you suggesting that the 25-30% of cases are done after each use?

 

[fuzzymarindave]

My understanding is that the case itself handles the pressure, not the rifle chamber. The alloy Federal uses doesn’t expand like a brass case does when fired.

I suppose it is possible that these alloy cases handle some or maybe most of the increased pressure. Weatherby offers the Mark V rifles in the 7mm Backcountry, however I notice that the 7mm BC offering is not available in the titanium receiver Mark V. I already know from experience that the Mark V titanium receivers don't handle pressure as well as the Mark V steel receivers, and this suggests to me that maybe there is some increased pressure from the 7mm BC that Weatherby was concerned about in the titanium receiver.

 

[djauofd]

Did you shoot them at distance as well? Are you suggesting that the 25-30% of cases are done after each use?

No shot this at an indoor range. Just to get me in the right zip code for field work. Yes 20 to 30% of the cases are expanding at the joint of the case head and body significantly enough to warrant them not reusable


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[ArgentJ]

No shot this at an indoor range. Just to get me in the right zip code for field work. Yes 20 to 30% of the cases are expanding at the joint of the case head and body significantly enough to warrant them not reusable


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And did you actually shoot them from an AR15(noted the magazine length loading) or use a bolt gun? That's really incredible performance either way, but really game changing if reliable from a MK12 or similar like you said. I would certainly like to keep the semi-autos in one caliber and another just for bolts.

 

[djauofd]

The 88 gr ELD M bullet performance results were from an AR 15 single feed with a sled. 2.495” COAL. I believe it was 25.6 gr of AR Comp. CCI 450 primers. Barrel was a Bull Profile Black Hole Weaponry P3 , 223 Wilde chamber with 1-8 twist.


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[djauofd]

I have thought of making a few 2.29” so they can magazine feed but I will really be eating up case capacity pushing them .2 “ back into the case. Using my SWAG method I am thinking AR Comp powder will be limited to 23.5 gr and speed will drop to 2,700 fps .

Single feeding these are ridiculous, You could give your DMR riflemen a bandoleer of say 20 single feed rounds and a sled. He could then proceed to stretch his rifle out to 1,200 yds at sea level and 1,375 at 5,000 ft elevation.

FYI the load was 25.6 gr AR Comp


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[ArgentJ]

I have thought of making a few 2.29” so they can magazine feed but I will really be eating up case capacity pushing them .2 “ back into the case. Using my SWAG method I am thinking AR Comp powder will be limited to 23.5 gr and speed will drop to 2,700 fps .

Single feeding these are ridiculous, You could give your DMR riflemen a bandoleer of say 20 single feed rounds and a sled. He could then proceed to stretch his rifle out to 1,200 yds at sea level and 1,375 at 5,000 ft elevation.

FYI the load was 25.6 gr AR Comp


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That is really cool. I'll have to get some ammo with these casings and a sled to try it out.

 

[djauofd]

That is really cool. I'll have to get some ammo with these casings and a sled to try it out.

Best thing is to buy the cases then you can roll your own. As I was saying getting more than one load in these cases can be done but there is major stress at the joining point of the case head and the case body. It is internally press fit through an oversized flash hole.

Shell Shocks spec sheets say they are one and done. Not to be reloaded. So reloading is at your own risk. I cycled some cases through three firings , but after analyzing structural concerns I have decided one and done. As I was loosing 30% in each cycle due to excessive expansion at these joint locations.

Shell Shock 5.56x45mm NAS3 Cartridge Cases - Pack of 1000

1,000 new unprimed NAS3 5.56x45mm cartridge cases. Shell Shock’s NAS3 cases:

shellshocktechnologies.com

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[ArgentJ]

Best thing is to buy the cases then you can roll your own. As I was saying getting more than one load in these cases can be done but there is major stress at the joining point of the case head and the case body. It is internally press fit through an oversized flash hole.

Shell Shocks spec sheets say they are one and done. Not to be reloaded. So reloading is at your own risk. I cycled some cases through three firings , but after analyzing structural concerns I have decided one and done. As I was loosing 30% in each cycle due to excessive expansion at these joint locations.

Shell Shock 5.56x45mm NAS3 Cartridge Cases - Pack of 1000

1,000 new unprimed NAS3 5.56x45mm cartridge cases. Shell Shock’s NAS3 cases:

shellshocktechnologies.com

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Thanks for the link, I hadn't seen that! One purchase could be a lifetime supply at the performance we're talking, so one and done is ok with me.