New Cartridge from Federal - 7mm Backcountry

[fseaman.js]

Looking how early weatherby jumped in on the release and the number of rifles they are chambering for it, I'm a firm believer it's just a 7mm-6.5 RPM with Federal's special Alloy.
They say they are going to be releasing the alloy in other calibers as well, that could be interesting, other new calibers or other existing calibers? Release an alloy 7mm PRC and your new cartridge is cooked. Release a new alloy 300 PRC and the industry goes nuts pushing the limits?? Or do people just blow up guns?

With the help of LRO members I modeled the cartridge in QuickDESIGN.

It's not like a PRC at all. the PRC is based in a 375 Ruger. This cartridge is good old 30-06 based like a 280 Remington.

1. Steel case. That is the "NEW" technology.
2. Shortened
3. 30º vs 30-06 15º

That is it for change to the parent case. The secret sauce is the steel case.

Weatherby rifles have been proven to handle immense bolt thrust so not surprising they are the first to actually list it. Seekins PH3 3 lug action would be the next to be able to take the pressure.

 

[Cornbinder57]

I believe if you look at the images they posted it a rebated rim cartridge just like the 6.5 and 338 RPM.
Poor comparison. On my side I realize it's not a PRC or a magnum. I'm just a firm believer it's what was next in Weatherby's RPM line up but federal partnered and put it in their new alloy.

 

[can1010]

I believe if you look at the images they posted it a rebated rim cartridge just like the 6.5 and 338 RPM.
Poor comparison. On my side I realize it's not a PRC or a magnum. I'm just a firm believer it's what was next in Weatherby's RPM line up but federal partnered and put it in their new alloy.

if you look at the prints in post # 20 & 28 you can see it is not rebated or based on the RPM case. 06 parent case.
this design has promise and looking forward to the future. converting quality 06 brass and using it for normal pressures and having the high pressure option like the 277 sig fury would be a plus.
hate when my mind starts working

 

[NotLongRange]

What interests me about this cartridge is the case metallurgy. Think of it this way…brass has been used for firearm cartridges for around 175 years with little change to the material used.

Material science, more specifically metallurgy, has advanced by LEAPS AND BOUNDS through that period of time.

If you have a stronger material capable of withstanding higher pressures, is relatively inexpensive, corrosion resistant, and with reforming properties similar to brass…you might have something significant.

 

[fseaman.js]

if you look at the prints in post # 20 & 28 you can see it is not rebated or based on the RPM case. 06 parent case.
this design has promise and looking forward to the future. converting quality 06 brass and using it for normal pressures and having the high pressure option like the 277 sig fury would be a plus.

Yeah, I that idea of standard pressures brass case works. If you are using long bullets, seated at caliber or neck length, even with the short Creedmoor it is too long for a true short action. Might as well use a 30-06 action and mag box.

I made some designs in 2014 very similar to the Backcountry. I called them the Fellowship series after Lord of the Rings. That is why I was able to model the 7mm Backcountry so fast. Already had very similar.

 

[fseaman.js]

Material science, more specifically metallurgy, has advanced by LEAPS AND BOUNDS through that period of time.

%100. Brass has always had it's pluses and minuses.

Plus, of malleable for resizing. For handloaders if of course big.

Re Federals "steel" case resizing, the status is "working on it".

Someone, pointed out that one of the things brass does is expand and "grip" the chamber walls. Reducing "bolt thrust". More than one has expressed concerns over this "bolt thrust". Maybe it's not an issue. It is an area where I don't have knowledge or experience. If it is true, Weatherby's can take it. The new 3 lug Seekins looks to be able to take it. The list of rifle makers that will offer "Backcountry" makes me think "bolt thrust" worries may be over stated.

Anybody know where to find bolt thrust calculations?

 

[NotLongRange]

That is also part of the case design. They are using a longer case (similar to an 06 case) so the case has enough bearing surface with the action to prevent excessive bolt thrust.

 

[can1010]

it's not just the length it is the very minimal case taper that grips the chamber walls preventing bolt thrust. the downside to minimal taper it also hides pressure and that could be dangerous, it will take a very experienced reloader to work with this case.