Federal New Cartridge

[walk2112]

Geissele just came out with a bolt gun chambered in 7BC and they're claiming far less than 1 MOA groups. If they were able to get this accuracy with this cartridge, it would be intrigueing, and the best accuracy we've seen on the interwebs yet. Typical geiselle pricing, north of 3k.....

I know this topic and argument is tired, but I also wonder how they define and measure a ‘group’ (shot count)

 

[mustelid_master]

I know this topic and argument is tired, but I also wonder how they define and measure a ‘group’ (shot count)

It is certainly worth asking. I believe they mentioned three shot groups in the video

 

[cowboy300]

I talked with an industry insider yesterday that was part of the initial testing of the 7 backcountry before it was released. They haven’t seen very good accuracy and also blew up a ti can on 20” barrel. I would strongly recommend if you are planning on using a suppressor you check with the manufacturer and stick with steel. The early federal ammo boxes that were sent to test had the pressure test data labeled on the box and it was 92000 psi on one lot.

 

[wyosam]

I am At sheep show this weekend and talked to the guy at the federal booth. He said that within the next 2 months we should see specific info coming out about reloading the 7BC. He said they are waiting to release all
Info at one time regarding dies and reloading the cases and everything else. He also said that it would be a 1 step pass through the dies and would not require any additional steps as I understood it but I had been drinking most of the day so forgive me
If I missed something. Just being honest

He also said they would be selling cases for reloaders as long as availability was available. And they are getting 7+ reloads from the cases without issue and are using standard large rifle primers


Obviously this is coming from a guy that was sent by federal to talk specifically about the 7BC because that’s what mainly was at the small booth so take that with a grain of salt but wanted to share.

Im not sure if I’ll go back to the show tomorrow as I seen everything I was looking for but if I do go back let me know if anyone has any questions they would like asked

It will be interesting to see what they came up with for single pass sizing. A sizing die isn’t rocket science and RCBS has been at it quite a while now. Seems like maybe voodoo, magic, and trying to put out sales-affecting fires might be involved.


Sent from my iPhone using Tapatalk

 

[BelowAverageBowhunter]

1..All actions are pressure test well beyond the 80 that would be a new cartridge. Hell I think I remember some said they tested them well above 100.

2. I am having trouble understanding the magnum bolt face problem you alluded too. F = P × A. I think that is right. Logic would dictate that if F which is bolt thrust and P which is pressure you would see an increase in P you will see an increase in the other. So the 7 MM BC does increase blot thrust.

You're correct on F=PxA

so if we take a standard bolt face pi(0.473/2)^2 * 80,000psi = 14,056 lbs of bolt thrust

a magnum bolt head pi(.532/2)^2 * 65,000psi=14,450 lbs of bolt thrust

Those are a little bit simplified because you should probably use the internal case diameter during firing not the bolt face diameter but those are awfully similar for it to be by accident. A magnum bolt face at 80,000psi would be 17,784lbs of bolt thrust. Almost all actions can probably take that but they design a safety factor into that that may not fly when you add 25% to the load.

 

[gerry35]

My favorite thing about the gun community. Everyone screams for innovation but when companies innovate the idea gets poo-poohed before it even hits the market.

Too many guys had an opinion on something they know nothing about.

 

[gerry35]

I'm not interested in a 7mm but find this a really interesting concept. Would seriously look at some kind of a 257 or 277 version.

 

[Unckebob]

I talked with an industry insider yesterday that was part of the initial testing of the 7 backcountry before it was released. They haven’t seen very good accuracy and also blew up a ti can on 20” barrel. I would strongly recommend if you are planning on using a suppressor you check with the manufacturer and stick with steel. The early federal ammo boxes that were sent to test had the pressure test data labeled on the box and it was 92000 psi on one lot.

I am not in the industry, but the ammo you are describing sounds like what they would send to rifle makers to test whether their action could survive a very hot load.

I would not consider any accuracy data from those loads as relevant to actual production ammo.

 

[SwiftShot]

You're correct on F=PxA

so if we take a standard bolt face pi(0.473/2)^2 * 80,000psi = 14,056 lbs of bolt thrust

a magnum bolt head pi(.532/2)^2 * 65,000psi=14,450 lbs of bolt thrust

Those are a little bit simplified because you should probably use the internal case diameter during firing not the bolt face diameter but those are awfully similar for it to be by accident. A magnum bolt face at 80,000psi would be 17,784lbs of bolt thrust. Almost all actions can probably take that but they design a safety factor into that that may not fly when you add 25% to the load.

That is going to be the kicker. They can probably all take it, bit then we get to reloaders pushing limits.

 

[BelowAverageBowhunter]

That is going to be the kicker. They can probably all take it, bit then we get to reloaders pushing limits.

The steel likely springs back farther than brass too, so you might not notice heavy bolt lift or some of our normal signs of overpressure until you're shaking hands with danger. I think most of us that have been reloading for awhile have pushed things a little to far a time or two and gotten heavy bolt lift. I would guess primers will still show pressure signs normally I wonder how flat they are under a normal 80,000psi load or if they did something with the case design to protect from a popped primer

 

[z987k]

The steel likely springs back farther than brass too, so you might not notice heavy bolt lift or some of our normal signs of overpressure until you're shaking hands with danger. I think most of us that have been reloading for awhile have pushed things a little to far a time or two and gotten heavy bolt lift. I would guess primers will still show pressure signs normally I wonder how flat they are under a normal 80,000psi load or if they did something with the case design to protect from a popped primer

The steel doesn't expand as much as brass and the case head holds the primer a lot better. They don't move at all.
If you're piercing primers, you're well past 80k.

 

[Andouille]

That is going to be the kicker. They can probably all take it, bit then we get to reloaders pushing limits.

The math above calculates thrust at back of the case, but doesn't account for friction of the case against the chamber wall, which is an important factor affecting forces at the bolt face. What is being missed here is that Federal states that the steel case grips the chamber and reduces bolt thrust compared to a brass case, and this is part of why they claim that modern actions are strong enough.

 

[Marshfly]

I'm not a reloader. I also have an old Rem 700 .270 that I cut to 18" that I'd really like to rebarrel to something that is designed to shoot heavy for caliber bullets more effectively. If this cartridge is successful, it or something similar would be absolutely perfect for what I want to do. I get to keep my short barrel, shoot the bullets I want, and get the speed I desire, all without much or any increase in recoil. Win all around.

I know a lot of people don't see the point in this so I just wanted to put my opinion of why this would work for me out there.

 

[gerry35]

Those who said it wasn't reloadable were wrong of course. I thought the experts on here said it would take 12 passes? Looks exactly what we are used to but with one extra step where you need to bell the case mouth before seating the bullet.

 

[tony]

Joe von Benedict had one of his better podcasts on the 7BC. It was a live Q&A and he didn’t go full blown shill.

 

[SwiftShot]

I am considering it. Put a 18 or 20 inch barrel on a nice action with MDT HNTR 26 stock folding. Perfect gun for North America. Shoot a 175 grain bullet. Bears, moose, elk, whitetail, sheep, and hogs.

 

[Okie_Poke]

Those who said it wasn't reloadable were wrong of course. I thought the experts on here said it would take 12 passes? Looks exactly what we are used to but with one extra step where you need to bell the case mouth before seating the bullet.

To be fair, the 12 passes thing came from Outdoor Life, supposedly based on a conversation with RCBS as they were working on dies. From John Snow’s article:

I know that RCBS is working on reloading dies for the 7 BC, and I’m eager to try them. But from what I’ve heard from RCBS, the dies are having trouble resizing the cases. In order to get them back to their original factory size they need to be run through the die multiple times — more than a dozen cycles, in fact.

The video looks promising, but it’s still not a commercial reality yet. I do hope it’s actually reloadable in practice, but I’m still waiting for others to work the kinks out. If quality cases become available (preferably from more than one source), and if the rest is as advertised, then I may get interested. Until then I’ll probably just be a Fudd about it. Someone needs to test it, though, so if it fits your rifle-buying parameters, by all means get one and let us know how it works. It could be a better 280 AI—which could be worth having.

 

[z987k]

It is better than 280ai.... provided you need that extra distance. I'm just looking at what a 280ai will do and then this and I'm like, we'll both shoot well past my minimum expansion velocity at hunting distances i should be shooting at... so why would I want the extra recoil of the 7BC?

 

[gerry35]

To be fair, the 12 passes thing came from Outdoor Life, supposedly based on a conversation with RCBS as they were working on dies. From John Snow’s article:



The video looks promising, but it’s still not a commercial reality yet. I do hope it’s actually reloadable in practice, but I’m still waiting for others to work the kinks out. If quality cases become available (preferably from more than one source), and if the rest is as advertised, then I may get interested. Until then I’ll probably just be a Fudd about it. Someone needs to test it, though, so if it fits your rifle-buying parameters, by all means get one and let us know how it works. It could be a better 280 AI—which could be worth having.

Thanks for the additional info on where that came from. We knew it would be a bit different when it came to reloading it so what they came up with sounds good with only one extra step. RCBS and others have to get it perfect before release so they are making sure it's going to work. The prototype dies Federal has sound like they are close and they could work with them but not quite there.

 

[gerry35]

It is better than 280ai.... provided you need that extra distance. I'm just looking at what a 280ai will do and then this and I'm like, we'll both shoot well past my minimum expansion velocity at hunting distances i should be shooting at... so why would I want the extra recoil of the 7BC?

I'm going to wait for a 277 version myself. Maybe Sig Sauer could make a deal with Federal and use their alloy for the 277 Sig Fury. This new alloy looks like it's going to be the future so at some point they'll have something that you'll like.