7 Backcountry case capacity

[Bobby Ball]

Hey Guys,
Does anyone have a measured case capacity (water) for 7 Backcountry? I searched here and all over online and failed. I'm inputting all of the same specs into GRT so that it's in the database but that's the one thing I'm missing right now to allow it to model accurately. Any help would be appreciated.

Thanks

 

[powdahound76]

@45-90 is the main guy posting about this.

$0.02 says it is posted in his thread titled Reloading the 7 BC

 

[Bobby Ball]

Yeah that was actually the first place I looked. I've been following that thread. I didn't want to hijack or derail what he had going on there.

 

[lash]

Well, that would actually be a good place for that question.

Is not measuring case capacity a part of the reloading process?

 

[MO Fugga]

Well, that would actually be a good place for that question.

Is not measuring case capacity a part of the reloading process?

Damn straight. A few tenths of a grain could be the difference between success and plastic surgery. And that's for a cartridge a fraction the capacity.

 

[45-90]

@45-90 is the main guy posting about this.

$0.02 says it is posted in his thread titled Reloading the 7 BC

The water capacity is 73.0 grains for steel and brass about 72.5 grains for Nosler brass. Almost identical to the 280 Ackley, shorter but a bit wider in the shoulder.
the slightly longer case is the 280 Ackley beside a formed brass and factory 7 mm BC.
You can basically use 280 Ackley load data to reload it.
But with long bullets like the 180, 184, 197, etc my rifle factory throat let's me load to over 3.5+" but the mag will support 3.7" long cartridges.
So the extra length moves the brass cased 7mm BC close to 7mm SAUM load data.

I made my own dies ...but dies are coming from Lee. The brass cases are easy to make from 280 Ackley... slight trim above finish length, then bump the Ackley 40° shoulder back with Redding 308 trim die just above finish at 20°... super quick..

Then finish with a full length 7mm BC die.

Now you have a cartridge made with brass cases that's like a 7mm SAUM or the wimpy factory 7 PRC loads in a 20" 7 mm BC barrel...any experienced handloader can make...but you also have the steel cases to out perform most factory 7mm cartridges in a 20" barrel with factory ammo including the 28 Nosler...most are below factory quoted velocities, while the 7mm BC has been 50 to 100 fps above factory quoted velocities in steel cases with factory loads.
It's the real deal for hunters who don't reload, which is most, but want that kind of performance from a factory gun and ammo....its also very accurate with factory ammo, especially for a hunting rifle my first 3 shot group was .160" with 170 gr at 3100 fps from a 20"
Check out the site reloading the new 7mm BC...I have posted factory chronographed loads and reloading both steel and brass cases...including subsonic loads and 180 gr bullets.

 

[Bobby Ball]

Thank you very much 45-90. I appreciate you taking the time to share. I'll plug those numbers in. That was very helpful.

 

[45-90]

I have been also asked about forming the steel cases to other calibers.
First ya have to buy factory ammo to get the cases...to expensive. Unless a shooter at your range is just throwing them away...cause he doesn't reload...or heard the rumor ya can't reload them.

But I took one that had 4 reloads on it and formed it to 30 BR ...so yes they can.
But it takes you to build the forming dies.
There may be some cases that do not require as much sizing and a combination of modified factory dies can be utilized.

My hope if this catches on the factorys will make other common calibers to facilitate those who do not want a 7mm.
But this is what we have for now.

 

[surprisingrerun]

That's some impressive resizing @45-90! How did you build the case forming dies to take it down to 30br?

 

[45-90]

That's some impressive resizing @45-90! How did you build the case forming dies to take it down to 30br?

That's a top secret invention, a million dollar idea, no die like it in the world at this point...I was hoping RCBC would figure it out to bring it to market.
Since they've been working on sizing steel cases for some time now, for the 7mm BC.
Lee has just released 7mm BC dies...I have ordered a set, to see if they did anything different...from the instructions it appears no.

It didn't take me that long to figure it out, the idea just came to me while I was making dies, and RCBS has many years building reloading dies.

Maybe they'll give me a call...and drop some coin in my pocket, then everyone can do the same thing...probably not.

But I will share all the other information on the 7mm BC for free.