8.6 blackout, opinions?

[SweaterDood]

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.

The fast twist is just an attempt to force the bullet to expand, when the velocity is too low to create hydrostatic shock. The .300 AAC Blackout was developed with a 1:5t barrel in mind. Nearly nobody actually uses them though. It does help with expansion, but so does an extra 1000-1250fps, which also has the benefit of energy and wound channel. The .300 AAC actually has merit as a supersonic cartridge, mirroring the ballistics of the 7.62x39 with 125gr bullets with reliable feeding from the more precise AR15 platform.

Personally I’d just use a .45 ACP over either Blackout variant for subsonic work. Bigger hole principle. And if using a large frame AR, I’ll stick to .308win or .358win with a traditional twist rate

 

[XTR]

458 SOCOM with 405s and a SiCo Hybrid. Run it at 1800FPS and it’s a semi 45-70, run them at 950 and it’s a 22LR gone “hulk style”. Both will kill deer effectively.

 

[Ray123]

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.

Yeah, the 8.6 Blackout is kind of a mixed bag....bad barrel and all...shot 130 rds today...so I have an opinion.
Be careful this 3 twist can be dangerous, when you push past subsonic to see what velocitiescan be achieved... I damaged the muzzle breake and the Magneto Speed bayonet several times ....after removing the brake. Push the velocities and bullets explode about 1" out of the muzzle...exciting....just blast the ground with a 6 to 10 foot circle of lead at 10 feet from the target, chunks of bullet lead and jacket everywhere, fired all the top high velocity loads in this manner...too dangerous to the Magneto Speed bayonet.
Fired 2 different 200 gr , 1 type of 225gr , 3- different 250 gr , & 285 eldm. The best load was Serria 250 BT 15 grains of 1680 7.2 S/D and 9 shots in .680" 1060 fps ave at 50 yards the range where all the shooting was done. So bottom line 15 grains of AA1680 for every bullet weight tried 200 to 285 in 16" barrel is roughly subsonic...1100 to 900 fps. But the 15 gr load AA 1680 & 285 eldm velocity was like a disappointment with 47 S/D..
Fairly accurate at 50 yards....but when pushed with 23 gr of AA1680 at 1450 fps the big 285 gr failed to make it to the target, no holes and saw dust kick up 5 feet in front of the target. Lots better luck with sub was 15.9 to 16.0 grains of IMR 4198 with the 285 eldm accuracy and group size. What's strange the cheap 200 gr Speer with 23 gr of AA 1680 with a velocity of 1640 fps is fairly accurate and stands up to the 3 twist , and works well at 1050 fps with 15 grs of 1680. Also shot some 250 gr fmj with 30 grain load of 1680 and it didn't explode. But 23 grains of AA 1680 worked as the maximum without bullet failure to 50 yds with all bullets except for the 285 eldm, they probably should be subs only which is the only way they reached the target in this 3 twist. The 3 twist is most suited for subsonic. All copper bullets may stay together at high velocity but I didn't have any to test. I would prefer a 6 twist for my application. So the 3 twist will wipe out your chronograph, your muzzle breaks, or your suppressor...soon as it leaves the support of the barrel there is a 1" of travel outside the muzzle and the bullet starts coming apart...as measured by the damage on my muzzle break, got through two baffles, came apart in the third. So test the bullets in a 3 twist without a muzzle device first, also note the Magneto Speed will take alot of bullet fragmentation abuse on the bayonet, and still read muzzle velocities....mine now looks like crap big chuncks out of it ....but ya gotta know the velocity. No wonder "the professionals" prefer 900 fps on the big bullets with the can on. That's my take ...I spent the time and money to find out about the 3 twist. Not really impressed, more unimpressed, with the performance so far. Several good groups with subs and if that's all I wanted out of it, it's okay for that. But I want some good maximum performance supers too, but you are very limited in bullet selection for that,... if it can be accomplished, with a 3 twist .. IMO, today, I'll trade ya for a 6 twist.

 

[megastink]

I think a short barreled 8.6 bolt gun would be a great brush gun for eastern PA where I hunt. I'm currently trying to sell a Savage 6 creed with a 16" barrel to fund a 8.6 build on a folding MDT chassis. Should be a great little rifle with enough thump even for black bear.

 

[SEM]

Just adding another thing to think on, I bet it would work fine in an AR 15 maybe

I had a magic barrel smith cut a chamber for me, had an un useful 338 barrel 1-10 sitting around and wanted a 338 squirt of my own, so dressed up into a contender barrel it was, Had to use what I had in dies and brass on hand ( no custom dies) so a 223 case cut at the beginning of the shoulder, 223 FL die and a 338 Fed seater, throated so the bullet seated out a LOONNNNGGG way, rather simple, second range trip 100 yards H4198 Nosler 200gr BT first three same hole just had to shoot a fourth .25 damnit... I am planning maybe to send the barrel in and have a rim cut so I can use 357 max cases.... I know dont fix what aint broke

 

[Ray123]

In case anyone is interested, still playing with the 8.6 Blackout...and its ridiculous 3 twist. Ordered some all copper bullets to see if they don't explode out of the muzxle like every lead bullet I've tried in the upper supersonic level. The Faxon load data with supers should be approached with caution..as it blows primers with me and other shooters...as well as muzzle devices we both destroyed, by bullet strikes.I ask Faxon for a 8 twist to make this cartridge versatile like a 300 Blackout, but this 3 twist is basically a 350 gr subsonic 900 fps at it's best, or other heavy bullets at less than 1000 fps...but the 350 gr bullets are unavailable.
So I made my own roughing die to take 30-06, 25-06, 270, 308, etc in one pass no annealing no dents in shoulder. Mill off excess in Bridgeport and lever collet fixture. Deburr...run through Lee FL die...neck turn into the 30 degree shoulder on the lathe with a carbide tool with 30 degree shoulder, no annealing needed no cases ruined..and all chamber great.
The case water capacities are as follows for different cases for those interested.
308 LC Military =44.5 gr H2O ( fired)
308 Win commercial = 45.5 (fired)
300 Savage Remington = 46.1 (the easiest case to form 8.6 from) (fired)
Hornady 308 = 45.2 gr H2O (fired)
Winchester 30-06 = 45.6 gr (unfired)
Lapua 6.5 Creedmoor Small Rifle= 45.2 gr (unfired)
So you can basically use any 30-06/308 based case to make 8.6 Blackout...and capacity will be fairly close, as you can see. But 300 Savage is the easiest very little trimming, and all the rest about the same with the 30-06 having a bunch to trim, but no problem, about a second to trim with a Bridgeport mill However the recommended 6.5 Creedmoor the most difficult because I use an extra step of running a 30 cal Wilson mandrel die a lube necks first. All the others no lube on neck & no mandrel die needed. In fact the special form die, needs no lube to go from 30-06 to 8.6, then trim in mill, deburr, spray lube and run through Lee FL die, lathe turn into 30 degree shoulder..and done...your 30-06 is now 8.6 Blackout...no annealing either...nice perfect 8.6 BLK cases, with beautiful 30 degree shoulders and turned necks.
But the 3 twist is still ridiculous, not needed according to Berger Stability Calculator you can shoot a 300 gr bullet at 0 altitude and -20 degrees at 900 fps and still have a stable bullet with a 8 twist in .338!!! So why the limiting 3 twist is beyond me...It, according on math wizard the 3 twist would only add 40 ft/lbs to a bullet not rotating...So it would maybe add 15 ft/lbs of energy to your 300 grain bullet with an 8 twist VS the limiting 3 twist...and the muzzle velocity fluctuates more than that! Faxon... show me the math ...not some clear gel that is not recognized as ballistics gel by the FBI. That's my experience with the 3 twist 8.6 so far...it's a limited sub gun with too much capacity. Still waiting on my 8 twist, but have not heard a word from Faxon. I can not recommend it, with a 3 twist for the average guy, and the 350 gr bullets are not available for subs... its most obvious use.

 

[Dnchrist1]

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.

Tromix now makes a neat 2-piece linear compensator for the 8.6 Blk thread. $95.00.

 

[Ray123]

Tromix now makes a neat 2-piece linear compensator for the 8.6 Blk thread. $95.00.

Good to know, but right now I'm working with no muzzle device to make sure the bullets selected do not blow up inside the muzzle breake, with the bullet & powder charge selected as super sonic side is explored.

 

[Hotguns]

I've built several 8.6 rifles in various configurations. Now that I shot several hundred rounds of 8.6, I really like it. It's accurate and it hits hard. I've had some great groups using various powders. I shoot only subsonic, with a silencer. I figure if I need more, I'll just choose a different gun. Im up to 15 deer killed with various subsonic rounds, 300 Blackout, subsonic 308, .44 mag, 45ACP, and lately, this season, 2 with a subsonic round with the .45-70.

I think where it really shines is short, backpackable type rifles. My next build will feature the new detachable stock with the Stern Defense RAB-AD. Shooting 300-grain bullets further than just about anything else and it's pretty hard-hitting. I have used mine for deer hunting yet, I just got in some 300-grain Makers bullets that I haven't loaded yet.

If you want something that is capable of killing anything in North America with shots that are as quiet as a .300 Blackout, that is great for horseback, 4 wheeling, toting around in the mountains or just sitting in a treestand I think it's a great choice.

My latest build is using a Remington 700 action, 3# Timeny trigger,a Faxon barrel cut to 10.5 and rethreaded for the more common 5/8-24 thread, an MDT LSS2 chassis, an SB tactical "brace" and a dovetail for use on a tripod.

I know it's not everyone's cup of tea, but if you shoot a lot of suppressed stuff as I do, it'll take stuff that the .300 Blackout is a bit light for. In my neck of the woods, it is killing big hogs outright and dropping them on the spot, whereas the big boys usually run off with the .300 Blackout hits. Even the subsonic stuff running about 1000 is blowing right through them.

Here's what I was working on today...

 

[Danger]

I built my 8.6B O gave this old man something to do Last year was a bad one for me 165 rounds of Chemo I have a 338 W Mag and 338 Lup I have a hard time with the kick so I thought what the heck this Blackout 8.6 sounded like a good deal.
My thought was a late Utah deer but winter kill was nasty no tags My gun shoots 185 gr CX under .500 at a 100 at 2000 and change Buddy it hits Hard maybe next year God Willing D

 

[mic2377]

I have a 300 BLK that I have shot extensively. If I actually wanted to hunt with subsonic rounds I would use a big bore (45-50 cal) cartridge with heavy for caliber bullets and a blunt/flat point. I just don't think the boutique expanding bullets are as reliable, and they are also extremely expensive.

A cartridge like this (450 Bushmaster, 458 SOCOM, 45/70, etc) also negates the issues with blowing up bullets with supersonic rounds.

As a fairly early adopter of the 300 BLK, I have seen all sorts of cartridges come and go, and there isn't really anything new under the sun.

 

[ebb]

There was a chapter in the Peter Senich book about Vietnam era attempts at a 338 suppressed rifle they were unsuccessful. They blamed the bad results on not being able to get a fast enough twist barrel. Sounds like if they did have one they would have had bullet problems too.

 

[mike mccormick]

Just my two cents, if limiting oneself to subsonic, more mass is more energy. Why wouldn't you go with the 458 socom? Trajectory will be similar on anything sub.

 

[dantiff2]

Just my two cents, if limiting oneself to subsonic, more mass is more energy. Why wouldn't you go with the 458 socom? Trajectory will be similar on anything sub.

Not everyone makes 46 caliber, rifle rated cans. They are not in the normal assortment for most companies. Everyone makes a 30 cal can! But you are 100% correct. Them big ole’ heavy 45’s sure are fun when subsonic and suppressed

 

[spaniel]

Not everyone makes 46 caliber, rifle rated cans. They are not in the normal assortment for most companies. Everyone makes a 30 cal can! But you are 100% correct. Them big ole’ heavy 45’s sure are fun when subsonic and suppressed

46 Bushwacker or 46 Hybrid will get the job done. I built a bolt action R700, 16", and run a Bushwacker on it. From 100 yards down range it sounds like someone opening a soda can back at the bench. 500gr Maker bullets that open into nice wide flowers even launched at 1050fps.

I was disappointed I didn't get to test it on a deer this year.

 

[LVLAaron]

I'm in the process of building one. By all counts, the 1:3 twist thing is a bunch of marketing wank from Q.

But I like to play, so I got 2 barrels. One is a 1:3 by Mos-tek and another is 1:6.5 from McGowan

 

[BKworkingman]

The fast twist is just an attempt to force the bullet to expand, when the velocity is too low to create hydrostatic shock. The .300 AAC Blackout was developed with a 1:5t barrel in mind. Nearly nobody actually uses them though. It does help with expansion, but so does an extra 1000-1250fps, which also has the benefit of energy and wound channel. The .300 AAC actually has merit as a supersonic cartridge, mirroring the ballistics of the 7.62x39 with 125gr bullets with reliable feeding from the more precise AR15 platform.

Personally I’d just use a .45 ACP over either Blackout variant for subsonic work. Bigger hole principle. And if using a large frame AR, I’ll stick to .308win or .358win with a traditional twist rate

I'm really interested in updates on new bullets and performance. Please share if you can?

 

[LVLAaron]

Some REALLY interesting gel tests here

 

[JayHHI6818]

I have a 14 inch Thompson Contender barrel chambered in 338 Whisper. Parent case is 7 BR and I’m shooing Nosler 300 gr HP competition billets. 10 grs of HP 38 and 300 gr bullet is doing 1004 fps. I shoot metallic silhouette with it and it sounds like you hit targets with a hammer.

 

[LVLAaron]

I was chasing my tail with the "published" data that Q provides. The info for the 300 SMK bullet was way under what it needed to be. I stole some information from another forum, and this all jives with reality. Had a great day shooting it today.


Sierra SMK 300 gr.

Powder: Accurate 1680 16.5 gr 1088 FPS

Powder: TAC 18.0 gr 1084 FPS

Powder: CFE BLK 17.0 gr 1088 FPS

OAL: 2.670”