8.6 blackout, opinions?

[nakneker]

I’ve been having a lot of fun with two 300 blackouts in an AR platform and one 300 BO in a bolt. The attraction is both subsonic and hypersonic. Naturally the 8.6 blackout looks like fun too, especially with this 1 in 3 twist. I can only imagine the fun that would be shooting suppressed. The fast spin may be a marketing gimmick or maybe it’s really something new and different that works.

My brother is building one, I may join in, I’m thinking about building one in a 12” AR and one in a 16” Bolt action.

Do you have one? What platform? Opinions?

 

[Ray123]

I looked at it, personally not interested it for a bolt gun and prices seem ridiculously high to me ...takes a 308 AR 10 platform, heavy for fast hunting compared to the 300 blackout, which runs on cheap brass and bullets if necessary. 338 bullets are more expensive, a little more recoil, powder, cut down 6.5 Creedmoor brass is expensive...and 230 to 250 gr 308 are pretty comparable to sub to 288 gr.. for hunting?
So I'd run mine on an AR 10 platform Faxon 3 twist barrel probably 16" cut to 14.5" and threaded and pinned break..no suppressor. Brass cut down LC 308, sized to 8.6, annealed, lathe neck turned if needed. Bottom line I'd spend a total of $249 for the chambered AR 10 Faxon barrel, take the other items of a 308 upper including adjustable gas block. Use my reg mags. Assemble and shoot...need some load data. And done...it would be slightly better for hunting sub-sonic because of increase in bullet dia than the 300 blkout but not much...and a 230 SMK has a higher BC...I ran a 250 ATip in my 300 Blackout, but it wasn't to accurate, but plenty accurate for hogs...then 300 blackout has a bunch of sub sonic bullets available, ...for hunting?... I'd use something else, like 300 Ham'r AR15 platform, a 6mm ARC, 6.5 Grindel, all super sonic. But that's just my opinion...and it's not as fun as something new...I'd go cheap... like I'll do, if I decide to try it...all ya lost is a cheap barrel & a set of dies. I Even have the bullets... have fun.

 

[dantiff2]

If you are content with wanting something in 338 and subsonic then maybe look into the 338 Razorback. It should be much cheaper to play with compared to the 8.6 BO aside from the bullet prices are the same. And if you really want to get serious step up to the 450 Bushmaster or 458 Socom for sub work. There's something magical about a 400+ gn chunk of lead @ 1050 fps that will put a smile on your face : )

Dan

 

[TreyOh8]

I would like to give the 8.6 a try. But no Faxon 16" Remage I can find now. Would prefer a shouldered prefit if I could find a fast twist barrel somewhere. It would be a bolt gun. Only want it for suppressor use. The ability to go with 300+ grain bullets would be a big step up from 190 gr 308.
8.6 is the reason I got an Impact barreled action recently to have a switch barrel setup, but still have a bedding job and load development to do for the 308, and dont have a scope for it yet. So it would be a while for me to get an 8.6 up and running. In the meantime look forward to hearing of other's results with it.

 

[Ray123]

I looked at the 338 Razorback, AR15 subsonic only a better option...the 338 Blackout very large case for subsonic, a heavy AR 10 platform and uses about 10 grs of AA 1680 powder as does a 225 300 BLKOUT. 338 Blackout very inefficient case for subs with that powder, 10 grs sub velocity to 35 grs for super sonics a tremendous amount of empty space...makes for large velocity variations. I have shot 308 very accurately in subs 175 in several bolt guns from 12 to 8 twist with a case full of Trailboss,for cheap subs. Also a real blast to shoot Sunsonic is the heavy 50BMG with Trailboss or Red Dot...and AP tiped bullets explode on plywood, rocks, thin sheet metal ar sub speeds....the impact & flash is much louder than the unsuppressed 50BMG. Blew the side out of a piece of .020 thin piece of metal tube, all black residue left on the jagged metal 4" long gapping hole from the tip explosion. Could try that on a hog..
The 338 Blackout is pretty impressive for an AR round but it's in AR 10, the 338 Federal would do the same basic thing for normal shooting except for subs...most likely not cycle the action, with Trailboss, which is the powder I'd like to try in 338 Blackout for subs if it runs the AR 10, but I doubt it produces enough gas...thats why AA 1680 is the only powder listed for 338 Blackout in the load data, as its produces enough gas to operate a gas gun. Seems like there would be another case between the two extremes that would work in AR 15 ...looked at the Grendel case, bumped one up to 338 and a 250 gr bullet fit the mag...
Still lookin at it...

 

[357Mag]

I’ve been having a lot of fun with two 300 blackouts in an AR platform and one 300 BO in a bolt. The attraction is both subsonic and hypersonic. Naturally the 8.6 blackout looks like fun too, especially with this 1 in 3 twist. I can only imagine the fun that would be shooting suppressed. The fast spin may be a marketing gimmick or maybe it’s really something new and different that works.

My brother is building one, I may join in, I’m thinking about building one in a 12” AR and one in a 16” Bolt action.

Do you have one? What platform? Opinions?

Nakneker -

Howdy !

I DK what application you intend for a ( 8.6mm ) subsoni cartridge/gun ?

I had a benchrest grade single-shot bolt rifle made, that was chambered for my .358" cal wildcat; which was simply the .357AutoMag case necked-up .001".... to allow use of .358" calibre rifle bullets.

The combo gave me great accuracy out to 350yd ( the farthesr I pressed my shots ), and I used it for both target works; and on groundhogs !

I made my cases from both 6mm and 7mm BR brass, which use SR primers. These choices include the possibility of using Lapua parent cases, if that holds appeal ?

Case length was 1.298". My best loads were 24gr WW296 under surplus Remington .358" cal 150PSPs.
These shot amazingly well, which I attribute to their being " plated " and not jacketed.
I also had good results shooting .358" cal 180gr bullets.

While 24gr WW296 gave great accuracy w/ safe pressures, the case was of course not " full ".
I do believe load density my wildcat featured likely was higher than what it might prove to be for the notional 8.6mm wildcat you mention ? Hmmm......

Were I to shoot the .358" cal wildcat today, I would use Cutting Edge' .358" cal Extended Range " Raptor " 150gr bullets, as this grain weight is the accuracy bullet wt for .358" calibre ( IMHO ). Cutting Edge does offer heavier .358" cal bullets.


With regards,
357Mag

 

[Louisiana Shooter]

458 SOCOM can be run subsonic and does a very good job as long as the proper bullets are used. As can the 450 BushMaster.

Subsonic big bores are the way to go if you don't want to use the 300 Blackout. The Blackout has a lot of specialty bullets that make it perform exceptionally well though. Cost wise..........the Blackout is the best by far.

 

[DDriller]

.338 spectre has been out for a long time and works well. If you want to hot rod it form your brass from 6.8 spc and can pretty well match the 8.6 blackout up to 300 grain bullets. Most spectre brass is made from 10mm magnum pistol brass and are limited to 37500 psi. With the 6.8 brass you can go to 57500 psi.

 

[Fuj]

My .27 cents worth !! Think M1 Carbine straight wall case and very
reliable. It was a sorry day when I sold my Inland. Either way, and
probably done already.....Take the Blackout case and neck up to 8mm.
Now you have the M1 carbine's big brother and use a more sensible
twist rate. Or just call it the "32 Whisper" which also was probably
done already.

 

[ebb]

I asked JD Jones about the 30 carbine case years ago and he said the base is so thin on the 30 carbine case that it cannot handle the PSI, so he used 221 fireball when he developed the 300 whisper.

 

[Fuj]

I asked JD Jones about the 30 carbine case years ago and he said the base is so thin on the 30 carbine case that it cannot handle the PSI, so he used 221 fireball when he developed the 300 whisper.

Yes Sir !! You need to use the ready 300 Blackout case to neck up
too .32 / 8mm.....Another alternative would to shorten a 350 Legend
and play with an even bigger payload. Let no bad ideas get wasted.....

 

[ebb]

I was thinking that the 30 carbine would be a way easier way to do it, just like you but i never thought about high pressure in the weak case. My thoughts were to make a better supersonic cartridge than the whisper/blackout but i needed a case that fit a .473 bolt face. What i acme up with was 30 BR with supersonic ammo to the best the case will produce, and subs with 220 or 240 grn SMKs with a powder like trail boss or something high volume/low power. I made 100 plus cases on Gary's neat die, got an 8 twist blank, and a Mauser action , I use 220 SKMs with my 300RUM so i have the habit-forming box size of the 220s. I am looking for a scope that has a lot elevation hash marks cause a sub 220 or 240 will not be the flattest shooting load on the block.

 

[GaryL1959]

I’ve been having a lot of fun with two 300 blackouts in an AR platform and one 300 BO in a bolt. The attraction is both subsonic and hypersonic. Naturally the 8.6 blackout looks like fun too, especially with this 1 in 3 twist. I can only imagine the fun that would be shooting suppressed. The fast spin may be a marketing gimmick or maybe it’s really something new and different that works.

My brother is building one, I may join in, I’m thinking about building one in a 12” AR and one in a 16” Bolt action.

Do you have one? What platform? Opinions?

A solution in search of a problem?

 

[Fuj]

I am looking for a scope that has a lot elevation hash marks cause a sub 220 or 240 will not be the flattest shooting load on the block.

And a 40 MOA rail.....

 

[uncle fester]

Siege Motor ballistics don't interest me for hunting.

I predict the round will never achieve popularity beyond a small niche of subsonic junkies who spent big money on Big Bore Suppressors.

In contrast, I can run my 300BO with my 30 Cal Can subsonic or I can run supers and get 30-30 like performance for hunting,

 

[nakneker]

Thanks for all the thoughts and opinions. Zack at Old Dominion Is building a 8.6 blackout now for a guy. Remage set up with a Faxon 1 in 3 Barrel. I’m gonna wait and see what the feedback sounds like. For whatever reason and maybe it’s just me falling for a gimmick the fast twist barrel intrigues me enough that I want to try one out.

Just like this thread points out there’s a lot of paths a guy could take and have fun with big and slow suppressed options. I’ll probably stick with 8.6 BO mostly because my brother is doing one and we always have fun building like rifles. First one we ever did was a 6BR and you know how that turned out, That’s how I found this website actually.

 

[Ray123]

Thanks for all the thoughts and opinions. Zack at Old Dominion Is building a 8.6 blackout now for a guy. Remage set up with a Faxon 1 in 3 Barrel. I’m gonna wait and see what the feedback sounds like. For whatever reason and maybe it’s just me falling for a gimmick the fast twist barrel intrigues me enough that I want to try one out.

Just like this thread points out there’s a lot of paths a guy could take and have fun with big and slow suppressed options. I’ll probably stick with 8.6 BO mostly because my brother is doing one and we always have fun building like rifles. First one we ever did was a 6BR and you know how that turned out, That’s how I found this website actually.

Just ordered an AR 10 8.6 Blackout barrel and factory dies, it'll be here in a few days. Made a forming die on my lathe to take 308 Lapua, LC, & Winchester or 30-06 to 8.6 Blackout in one pass no lube no annealing...tried it on old scrap cases...these cases, appear to need neck turned. But interesting that Winchester 308 commercial brass, appears to be a close go brass wise without turning necks, depending on the chamber neck clearance when the barrel arrives. Most 6.8 reloaders seem to be sizing Hornady 6.5 Creedmoor brass with no neck turning. Also picked up some 285 gr eldm ...going to run some super sonic to see how fast they can go, and what affect the 3 twist has on bullets... should be a fun experiment, outside the box thinking on this cartridge...may have little effect, or be a dud ... but we'll see.

 

[nakneker]

Just ordered an AR 10 8.6 Blackout barrel and factory dies, it'll be here in a few days. Made a forming die on my lathe to take 308 Lapua, LC, & Winchester or 30-06 to 8.6 Blackout in one pass no lube no annealing...tried it on old scrap cases...these cases, appear to need neck turned. But interesting that Winchester 308 commercial brass, appears to be a close go brass wise without turning necks, depending on the chamber neck clearance when the barrel arrives. Most 6.8 reloaders seem to be sizing Hornady 6.5 Creedmoor brass with no neck turning. Also picked up some 285 gr eldm ...going to run some super sonic to see how fast they can go, and what affect the 3 twist has on bullets... should be a fun experiment, outside the box thinking on this cartridge...may have little effect, or be a dud ... but we'll see.

I hope you share the results and your thoughts, sounds like fun to me!

 

[Ray123]

I hope you share the results and your thoughts, sounds like fun to me!

The 8.6 Blackout Faxon barrel and parts to build. I was surprised at the poor quality of the 1-3 rifling. Cleaned it looked at it with a bore scope. They haven't got the 1-3 rifling perfected yet, IMO. It's like the clearance on the button is not right. Polish ed it with Iosso & Kroil and fine metal chunks was coming out of the bore. Burrs on rifling, reamer marks, little pieces of metal missing from the side of the rifling, pin holes & in one area inclusion across 1 section of bore, its worse at the chamber end and gets better towards the muzzle.
So I spent a bunch of time lapping it. Fine slivers of barrel metal coming off the rifling burrs...Can't do anything about the tears and inclusions, but its better. Assembled and ready to go...except I have to make a muzzle device...18 X1.5 MM muzzle thread. Tried a mock up round in 308 Win from Win brass, (in homemade die, trim to length & finished full size, in Lee Die ) which is thinner than Lapua or LC ...and it chambered nicely. Specs on my barrel 16" .104 dia gas port, so installed an SA adjustable gas block. Neck diameter on Faxon chamber is .368" so .364" to .362" is where I'll run this autoloader. So I'll machine cases, unless factory 8.6, which I don't have. But I have plenty of 308 Win....build muzzle breake, make cases out of 308, load, and test. I'm going mostly for supersonic, cause the loads for subs is already available. Put a lot of work into this marginal Faxon 3 twist ...hopefully there will be some accuracy. Probably why no one is shooting groups on paper, with these barrels ...just steel. If I like the cartridge, and the barrel in really inaccurate...I have a fire forming barrel.

 

[nakneker]

The 8.6 Blackout Faxon barrel and parts to build. I was surprised at the poor quality of the 1-3 rifling. Cleaned it looked at it with a bore scope. They haven't got the 1-3 rifling perfected yet, IMO. It's like the clearance on the button is not right. Polish ed it with Iosso & Kroil and fine metal chunks was coming out of the bore. Burrs on rifling, reamer marks, little pieces of metal missing from the side of the rifling, pin holes & in one area inclusion across 1 section of bore, its worse at the chamber end and gets better towards the muzzle.
So I spent a bunch of time lapping it. Fine slivers of barrel metal coming off the rifling burrs...Can't do anything about the tears and inclusions, but its better. Assembled and ready to go...except I have to make a muzzle device...18 X1.5 MM muzzle thread. Tried a mock up round in 308 Win from Win brass, (in homemade die, trim to length & finished full size, in Lee Die ) which is thinner than Lapua or LC ...and it chambered nicely. Specs on my barrel 16" .104 dia gas port, so installed an SA adjustable gas block. Neck diameter on Faxon chamber is .368" so .364" to .362" is where I'll run this autoloader. So I'll machine cases, unless factory 8.6, which I don't have. But I have plenty of 308 Win....build muzzle breake, make cases out of 308, load, and test. I'm going mostly for supersonic, cause the loads for subs is already available. Put a lot of work into this marginal Faxon 3 twist ...hopefully there will be some accuracy. Probably why no one is shooting groups on paper, with these barrels ...just steel. If I like the cartridge, and the barrel in really inaccurate...I have a fire forming barrel.

Disappointing observations on the Faxon Barrel. I admire the tenacity though. It’ll be interesting to see what it does in the accuracy and ES depts.