6.8MM BISON SUBSONIC PLATFORM (6.8 BSP)
New, from Bison Armory:
The Bison Armory 6.8 BSP consists of a rifle chambered in 6.8 SPC II, with a fast 1:7″ rifling twist rate and a 6.8 SPC cartridge loaded with a custom made 200 grain bullet. The purpose of this configuration is to create an effective combined subsonic / full power platform for hunting and tactical situations.
The 6.8 BSP takes advantage of the properties of the 6.8 SPC cartridge to provide the ideal platform for dual suppressed subsonic and full power applications. The key to the 6.8 BSP is the combination of the heavy bullet and barrel with stabilizing twist.
Note, I’m part owner and only learned about this a couple of weeks ago.
January 17th, 2012 at 10:56 am
:raises hand:
So is this a new load or just a heavier bullet in 6.8 SPC? I’m confused by the terminology not the physics.
Can I safely shoot 6.8 SPC in a 6.8 BSP weapon and vice versa? I understand that with the twist rates it probably won’t be accurate.
January 17th, 2012 at 11:28 am
Me Too: What are they getting in terms of FPS? And if one doesn’t care about Subsonic, what can one expect if the Bullet goes down to, say, 140-160 grains? Sounds like I can have one of my Favorite rounds, the 6.5 Swede in a modern package if they go that way.
I know, I know, 6.8 isn’t 6.5. Close enough for Government Work, though.
January 17th, 2012 at 11:34 am
I have noticed that government work also means massive collateral damage..
January 17th, 2012 at 1:02 pm
I know ultra-long-range is not the purpose, but I can’t help wondering what’s the ballistic coefficient on that long bullet there?
January 17th, 2012 at 1:38 pm
The 6.8 BSP is a “platform”, not a caliber/cartridge designation. The cartridge is exactly a 6.8 SPC, the barrel is different.
You can safely shoot 6.8 SPC ammo in our 6.8 BSP barrel. You can safely shoot 6.8 BSP ammo in a slower twist 6.8 barrel, but the bullet will tumble and keyhole.
YOU CANNOT SHOOT THE 6.8 BSP IN A NON 6.8 BSP BARREL WITH A SILENCER! Doing so would risk a baffle strike.
Good question! We don’t know yet. SSA is releasing a new 140 grain round that we hope to test soon. But this round should stabilize in an ordinary 6.8 1:11 twist or faster barrel, so there’s really no point in buying a BSP barrel if you don’t ever plan to shoot subsonic.
The point of the 6.8 BSP is primarily as a fun to shoot suppressed round where quiet is key, and also for serious hog hunters who want to drop a big pile of hogs around a water hole, for example.
January 17th, 2012 at 1:54 pm
What kind of numbers are you getting at 100 yds with the heavy bullet subsonic?
I’d be interested in the 140-160 gr numbers as well as that could make for a good caribou load. Maybe even moose depending on the bullet construction.
January 17th, 2012 at 2:25 pm
Matthew, we shoot sub 2″ groups at 100 yards. The bullet wobbles a little in flight which we find to be a good thing as there’s unlikely to be any bullet expansion at subsonic velocity, so the slight coning of the bullet ought to make it more damaging on impact. 2″ at 100 yards is fine as well because subsonic is useless past an absolute max of about 150 yards anyway.
Don’t have any test numbers with the 140 grain loads yet. SSA just came out with one we’d like to try, but you can shoot this, according to them, in a 1:11 twist barrel, so the BSP twist rate is not needed. Don’t know of any load data for the 160. We may work this up. That bullet is likely to be SLOW out of a 16″ barrel though.
January 17th, 2012 at 2:26 pm
Lastly, the 140 grain SSA load… I’d most likely run that through a 20″ 1:11 barrel to maximize performance. No point shooting that out of a 16″ barrel in my opinion.
January 17th, 2012 at 2:30 pm
This makes me happy in my pants.
January 17th, 2012 at 2:36 pm
Must be one heck of a twist rate to go from 110 gr to 200 gr. The 200 gr. has a huge BC.
January 17th, 2012 at 2:50 pm
Whats happens to the 90-110gr 6.8 full power load in a 1:7 twist? Will the lighter/ thinner HPs start to fall apart spinning that fast?
January 17th, 2012 at 3:48 pm
MAN….that is a LOT of bearing surface!
January 17th, 2012 at 4:33 pm
Ben,
Thank you. I wasn’t clear though, I was asking about MV and energy estimates.
January 18th, 2012 at 2:28 am
I just dont see how you could achieve anything close to the same f.p.s. and energy with the longer bullet design I mean the bullet is almost as long as the case where would the powder go.
January 18th, 2012 at 3:27 am
The 6.8 BSP will likely loose a bit of muzzle energy, but likely 50 fps or less. We have not chrono’d the round with full power yet but we plan to in the Spring when the snow melts.
Twist rate has a marginal affect on muzzle velocity and chamber pressure.
January 18th, 2012 at 4:12 am
Here’s some fun.
January 18th, 2012 at 9:24 pm
Ben,
according to Farmer Frank,
http://frankwjames.blogspot.com/
you only get one shot at a group of hogs, even with suppressed weapons. Says the slap of the slug hitting the hogs hide sends the rest scrambling for the hinterlands pronto. He specializes in hog eliminations, BTW.
January 18th, 2012 at 10:09 pm
Will, that may be true, and I have no first hand experience. On the other hand, that’s not what my customers tell me. Suppressed is one thing, subsonic suppressed is an entirely different thing.
January 19th, 2012 at 1:43 pm
A huge benefit of hog hunting subsonic is not whether it scares off the sounder of hogs after the first shot, it is several things. First is that it has more of a tendancy to confuse them, secondly is that a sounder that is a few hundred yards away are usually not spooked and you can make that you second effort while hunting hogs, third is that if you are hunting from a stand or blind, other hogs nearby will mostly likely not be spooked by the shot of an unsppressed weapon and lastly, you don’t blow the ear drums out of your hunting partner 🙂 and don’t annoy any neighbors nearby.
I believe the 6.8 BSP is a great approach. As with the 300 Blackout, bullet expansion is always an issue. Trying to get a subsonic bullet to perform/expand is a challenge, this is the right approach as the 6.8 easily outperforms the 300 BLK at supersonic speeds, I know I have 2 300 BLK’s and 3 6.8’s. Hopefully other manufacturers start developing bullets with better performance at sub velocities.