What’s going on here?

[Koda_]

So does this mean bolt gun architecture would safely handle more chamber pressure than a gas gun architecture?

But what I really dont understand is why would they separate load data without renaming the higher pressure one? This seems like it could create confusion leading to a safety issue not unlike shooting a 357magnum in a revolver only designed for a 38spl. At least there, the ammo is labled totally different.

 

[HNDLDR]

So does this mean bolt gun architecture would safely handle more chamber pressure than a gas gun architecture?

It's not that the bolt gun architecture will safely handle more pressure. If you completely closed an adjustable gas block on an AR and ran it like a bolt gun it would handle the same pressure as a bolt gun.
Where you run into problems is the gas gun is taking pressure at a certain point of the barrel and venting it back to cycle the action. There is an ideal amount of pressure to do this well without over doing it.
If you change the position of the port in the barrel, change the powder burn rate, shoot heavier bullets, change the port size in the barrel all effect the amount of pressure getting back the action to cycle it.

I do not work for Hornady or any other ammunition or rifle manufacturer so I can't speak for them. I suspect the reason they may list two separate lists of data for gas guns is because any Homer Simpson can order parts from 8 different manufacturers on the inter webs. In less than a case of Duff beer in his garage he can build his dream AR rifle without a clue of how the system operates and how to balance the gas pressure to operate correctly. The manufacturers have to safely account for this as best they can.

It's a lawyer safe world we live in.

 

[quigley257]

So does this mean bolt gun architecture would safely handle more chamber pressure than a gas gun architecture?

But what I really dont understand is why would they separate load data without renaming the higher pressure one? This seems like it could create confusion leading to a safety issue not unlike shooting a 357magnum in a revolver only designed for a 38spl. At least there, the ammo is labled totally different

This is far from the first time there is separate data for different guns. Check your loading manuals and you will find low and high pressure data for 45 Colt, 45-70 Govt, and others, strictly based on the platform they are designed to be fired in. The different pressure 6ARC data is clearly labeled as Bolt Gun and Gas Gun data with proper explanations.

 

[MaxRager]

This is far from the first time there is separate data for different guns. Check your loading manuals and you will find low and high pressure data for 45 Colt, 45-70 Govt, and others, strictly based on the platform they are designed to be fired in. The different pressure 6ARC data is clearly labeled as Bolt Gun and Gas Gun data with proper explanations.

Hopefully….you just ended the debate!

 

[Zen Archery]

My buddy Shawn had same issue with his AR10 308 Christensen Arms. Is it older ammo?

 

[asd9055]

I and three of my friends had issues with Hornady ammo in 300WBY, 30/30, .243 and 300AAC. I am glad Hornady is trying to explain it now, but I have a standard 300AAC, 16 inch barrel, pops the primers out. The only brand that does it. Its a factory rifle, CMMG. I buy Hornady projectiles, I have used Hornady dies, and other tools, I just avoid their ammo. In 300WBY we had three different MKV, three different shooters, all over the place. They gave me their ammo, I pulled the bullets and re-used the cases and projectiles.

 

[HNDLDR]

My buddy Shawn had same issue with his AR10 308 Christensen Arms. Is it older ammo?

Was it Superformance ammo or Superformance powder in hand loads?
Quigley257's link in post 29 does an excellent job of explaining issues with Superformance in gas guns.

 

[dustbag]

My buddy Shawn had same issue with his AR10 308 Christensen Arms. Is it older ammo?

I don't know. I would assume 3 years at most.

 

[mongo4567]

I have a buddy that had an issue with a certain batch of Hornady 308 superformance. I think they replaced the ammo.

 

[skipglo]

Dual ejectors plus a hot load View attachment 555897

X2.....if you or your buddy reload....I'd pull a bullet and weigh the charge also to be sure it's not really " SUPERFORMANCE" ...then you would definitely have legs to contact Hornady if it's the load

 

[Citified]

I ran into this same situation on a 16" .308 I built. It was over gassed so much it would
almost rip the rim off the case. The fix was to reduce the gas pressure at the block and install a heavier buffer to increase the dwell time before extraction. Works fine now.

 

[HNDLDR]

For any of you who are still wondering about the 6mm Arc in a gas gun, I stand corrected. The Arc has a larger case head then a 5.56. The bolt has to be machined out to fit the larger case head. The reduced material coupled with the higher bolt thrust from the larger surface area has broken the bolt lugs on AR rifles. This is why they have different load data for the 6mm ARC gas guns.

My apologies for implying anything otherwise.

 

[cajun]

View attachment 556156
View attachment 556157

The arc is based on the grendel case which has a fat head for a standard ar bolt. Thus it cant take as much pressure as a 556 bolt which has more meat on it. In a bolt gun this is not an issue. The grendel has the same issue. Saami max is lower than a 556 or even 6.8 in a gas gun.

 

[dustbag]

I wouldn't think he'd be worried about replacement. He is gonna reload for it going forward.