New Federal 7mm Backcountry “Ammunition Reinvented”

[RR 314]

I got one when it came out in 1980. My favorite deer round.

I started my son on a .22-250 and moved him up in a couple years to the 7mm-08. It is quite a popular round in Texas for all age groups. It is deadly on deer, pigs, etc.

 

[BeeMaa]

You have simply misunderstood what "m" means. In this equation "m" is the entire ejecta mass, which includes the bullet and powder charge.

If you run the equation all things being equal and include the powder charge as part of "m" you'll see the difference between a smaller charge doing the same work. It isn't much, but the answer to your question is "physics".

A 7 lb rifle is 49,000 grains plus the 225 grain cartridge is 49,225 grains for a 7BCT. While the other is 49,245 grains with all other things being equal.

Congratulations. You have saved 0.041% of the mass.

I wish you the best of luck in feeling the difference on your shoulder or seeing better performance on game.

 

[Datchew]

A 7 lb rifle is 49,000 grains plus the 225 grain cartridge is 49,225 grains for a 7BCT. While the other is 49,245 grains with all other things being equal.

Congratulations. You have saved 0.041% of the mass.

I wish you the best of luck in feeling the difference on your shoulder or seeing better performance on game.

Don't forget to take the different mass of the new case material into account. Maybe that gets us down to 0.0405%

Stuffs gotta be less dense than brass.
Every atom of mass matters.

 

[Doug Hamilton]

I got one when it came out in 1980. My favorite deer round.

I know that mine flattened the last blacktail buck I shot at. 140 grain AccuBond.. I think.it's a great and capable deer.round. That doesn't change the fact that you don"t see many for sale and very little ammo available in California or Washington. The rest would f the country, I couldn't say. Seems to be kind of a "niche" cartridge.

 

[375Ruger416]

JBM - Calculations - Recoil

jbmballistics.com

Actually, the powder mass, bullet mass, and bullet velocity determine the recoil generated by the cartridge. Rifle weight is inversely proportional to recoil (obviously). Cartridge pressure doesn’t play a role. The éjecta consists of the burnt powder and the bullet and how fast they are traveling when they leave the muzzle is what determines the recoil energy.

Theoretically at least the lesser powder charge of the 7 BC will result in lesser recoil for the same bullet weight and muzzle velocity. How significant this is I am skeptical, but more recoil is never an advantage.

 

[Wooster]

I think it's good that companies are still trying to innovate in this space despite improvements being very incremental. I learn from it, just like I've learned more about the factors that affect recoil from this thread, and enjoy the process. But I have noticed that some people (present company on AH excluded of course possess a temperament that leads to "status quo bias" and are unsettled by new innovation, as they are emotionally invested in what they already have. IMO, better we have companies trying to make and sell us stuff than ignore us.

 

[CastShooter]

A 7 lb rifle is 49,000 grains plus the 225 grain cartridge is 49,225 grains for a 7BCT. While the other is 49,245 grains with all other things being equal.

Congratulations. You have saved 0.041% of the mass.

I wish you the best of luck in feeling the difference on your shoulder or seeing better performance on game.

Congratulations! You proved what Federal claims, reduced recoil. That's marketing bud, it's a measurable difference so it's a claim that can be made and isn't false.

I'm not sure why you've got your pants in a twist, I surely don't. This is a hobby, lighten up a hair.

 

[sgt_zim]

I started my son on a .22-250 and moved him up in a couple years to the 7mm-08. It is quite a popular round in Texas for all age groups. It is deadly on deer, pigs, etc.

I've wanted one for ages, but I needed something that would give me 400-500 yards of reach, so I went with a 280 AI (my only "long range" hunting rifle). If the missus really gets into Africa the way I think she is likely to, I'll get her one. What I really want is a 7x57, but we're both lefties. And if I'm going to get a 7x57, I just can't bring myself to convert a LH push feed to that cartridge.

A already have a 6.5x55, and I have a bugger of a time heading into the deer and hog woods on deciding between it and my 45-70.

 

[crackerman]

I’m in the solution looking for a problem camp.

While it’s great to see companies innovating this seems like Federal is trying to mark their own niche like Hornady did with a PRC family. Which in and of itself is a lot of capabilities I don’t think anybody asked for. And remember those started out as competition ideas even before the hunting ideas.

I think this forum is probably not filled with their target demographic as it seems with the name, backcountry and favoring shorter barrels with suppressors. They are going for the western Hunter market that rightful or not believes that they can shoot elk at 800 yards and are at least smart enough to use something better than a 6.5 Creedmoor to get there.

I will be curious to see if we will have a family of backcountry cartridges come out similar to PRC or the new arc but as many here have said there are a few things at a .30-06,308 or .375 haven’t been solving for the last hundred years that this due cartridge addresses

 

[Cheesehead]

JBM - Calculations - Recoil

jbmballistics.com

Actually, the powder mass, bullet mass, and bullet velocity determine the recoil generated by the cartridge. Rifle weight is inversely proportional to recoil (obviously). Cartridge pressure doesn’t play a role. The éjecta consists of the burnt powder and the bullet and how fast they are traveling when they leave the muzzle is what determines the recoil energy.

Theoretically at least the lesser powder charge of the 7 BC will result in lesser recoil for the same bullet weight and muzzle velocity. How significant this is I am skeptical, but more recoil is never an advantage.

Based on all the online recoil calculators what you said is true, but I think these calculators oversimplify what is happening by ignoring cartridge pressure and barrel length. I think cartridge pressure does affect recoil. Here's why:

We know that pressure is equal to force divided by area (hence the psi units). So that means that the peak force acting on the bullet, and therefore also acting on the breech of the rifle is equal to the peak pressure times the area the force is applied to. Obviously, case pressure if measured is actually a bell curve of some kind, and the area under the curve would be the actual work done. But I haven't done calculus in over 15 years and don't plan to start now. Just comparing the peak pressures can tell us something about the recoil. If this cartridge has a peak pressure of 80k psi, so a about 33% more than a more typically 60k psi cartridge, that translates to about 33% more force acting on both the projectile and the rifle.

Since Force equals mass times acceleration, this additional 33% force would mean greater acceleration of the projectile. A lot of the additional force is needed to overcome the greater frictional forces resulting from the increase in acceleration. That's how they can reach the same muzzle velocity in a shorter barrel. This also means greater acceleration of the rifle rearward into your shoulder.

So, while the actual recoil energy may be the same, the acceleration of the rifle would be greater. I think this would make the recoil feel sharper, for lack of a better term.

 

[BGHNTR416]

If it weren't for companies continually trying to innovate, we would still be hunting with flintlocks...or maybe pointy sticks and rocks.

 

[Doug Hamilton]

Federal says it's reloadable. We'll see.

According to John B. Snow, writing for Outdoor Life and posted on Jan. 7, RCBS is working on dues for this cartridge but are having trouble with resizing the case. Hornady does not have a powder that will match the Federal loads. The steel in the cases cannot be annealed , so the case life will be short, if they can be reloaded at at all. Snow did not feel that the potential for reloading this cartridge is promising. That pretty much lines up with my initial feeling, but as yoh said, "we shall see."

 

[Puddle]

According to John B. Snow, writing for Outdoor Life and posted on Jan. 7, RCBS is working on dues for this cartridge but are having trouble with resizing the case. Hornady does not have a powder that will match the Federal loads. The steel in the cases cannot be annealed , so the case life will be short, if they can be reloaded at at all. Snow did not feel that the potential for reloading this cartridge is promising. That pretty much lines up with my initial feeling, but as yoh said, "we shall see."

So far, it doesn't sound promising for handloading. Federal won't break a sweat over it as handloading accounts for at best 10% of the shooting market.

You must have meant Hodgdon, not Hornady wrt a suitable burn rate powder that will keep up with the factory load.

We'll see.