300 BO, 6.5 G, or 6 ARC?

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Viking264

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I'm building a new upper, and am at the inevitable and unenviable point of determining cartridge. The purpose for this build is to be handled by my wife during predator situations on our farm. We deal with everything here from the smallest fox species to black bears in the 550+ range. Range to target will generally be less than 75 yards, much closer during the seasons when foliage is present on the encroaching woods. I am a hand loader, and have a fairly good stock of 6mm, 6.5mm, and 7.62mm projectiles on hand. The issue is brass.

What I'm seeing right now is that 300 BO brass is readily available, 6.5 Grendel almost non-existent, and 6mm ARC completely unavailable, however this is a long-term thing and shortages generally rectify themselves over time, so I don't want to make this decision based on brass availability alone unless someone can offer up some credible inside info that 6.5 Grendel and 6mm ARC brass are going to be largely unavailable for the next couple of years. I work in an industry where inside information circulates, so I don't think that it's unreasonable to "throw it out there". I don't want to screw around with re-sizing other cartridge brass down to either 6.5 Grendel or 6mm ARC; I just don't have time. I have even kicked around the idea of going 7.62x39. I'm not interested in 22-cal offerings; they are too small for me to be comfortable with in this application.

My wife is not recoil sensitive; when a predator is bearing down on your livestock, you could shoulder a Howitzer and not flinch, and she's a Kansas farm girl. If someone would like to chime in with an alternative suggestion that might have appropriate energy and available brass to boot, then please do so. Many thanks for taking the time to read this.

Best,

Chris
 
I haven't visited ammoseek in some time; I had already come across Arm or Ally, but wasn't too keen on the pricing. I'll keep it in mind.
 

MDWS 6mm Mongoose Premium SPR Barrel – 22″-20″, 5R Rifled, 1:8 Twist, Threaded 5/8-24 or Recessed Target Crown | MDWS

maddogweapons.com maddogweapons.com

6 Mongoose aka 6x45 - works in a standard AR-15 with only a barrel/upper swap out, uses LC brass from 5.56 loadings with one expander mandrel passed through the necks one time, uses standard AR mags, will run the heck out of a Hammer bullet. That said a 300 BO with the 101 Hammer or 100 Tac-X will absolutely run fast enough to be considered for this also.

Are bears a realistic threat? If they are a 45-70 lever gun with CE monos is the right answer to stop a charging bear. Don't pussyfoot around about it, get the cannon if the worst case is going to actually happen. But if the 99.9% use case here is a fox or a coyote any of the above will work
 
There's a massive difference between the mentality of black bears vs brown bears, so keep that in mind. Black bears are generally non-confrontational unless they happen to be a sow with cubs (this has been my experience throughout the past 14 years of living amongst them). Even the largest males will do little more than give you a faux-charge by taking a couple of steps towards you, but they're not the aggressive bears that you read about in hunting novels and the like. Don't get me wrong, a faux charge is enough to get your heart going. We're not going out and trying to actively engage them; it's entirely a case that we catch them in the act, always at night, so there's no charging involved.

To answer your question, bears are a persistent threat to livestock here, particularly in the dead of winter when there's little "natural food" in abundance and layers of ice on the ground can insulate a bear (or anything else) against being lit up by a standard electrified fence. Bears do not hibernate; they enter torpor, and even in the worst winter conditions they're active. This being the case, they're around all year long. I believe that a 110 or 120 Barnes coming out of a 300 BO at supersonic MV would do the job, however I am thinking hard about the Grendel loaded with a 120 TSX or something similar.

The majority of the predators around are coyotes and smaller critters.
 
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Believe it or not we have blackies here as well as their much larger meaner cousins. A 99gr. Hammer at 3000fps is good for ALL KINDS of critters, some of em way out there!!! Look at you-toob for some Grendel kills, I think you'd be impressed. One thing that hasn't been discussed is recoil. for most of us recoil out of an AR15 platform is a joke, however I can get some pretty dang fast accurate follow up's with the Grendel... My wife calls it pew pew Grendel, it's her favorite rifle to shoot!!! I'm seriously considering putting a suppressor on it!!!
 
I lived in northern Utah for several years when I was a kid; I recall seeing black bears in the Wasatch on a number of occasions, but they always kept their distance. Can't recall having seen any brown bears during those years; not something I'm likely to have forgotten.

I'm leaning towards the Grendel at present. My AR10 is a .260, but it's too heavy and large for my wife to comfortably handle, hence looking into converting the existing AR15 to something size-appropriate. I have more 6.5 mm projectiles than anything else (all of my deer hunting is done with a hot 6.5x55). Perhaps I will go the Grendel route and accept the fact that brass is going to be relatively expensive and not readily available for a while. I've got a number of powder options to choose from which ought to perform.
 

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