8.6 Blk reloading info
- Thread starter unclemoak
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I guessing on the bullet....you mean, the little AR 15 338 ARC Imp running over 3700 fps... the bullet is a 9mm 50 grain copper, re-machine in a lathe collet to .338"... also used in AR 15 9 mm 16" at 2640 fps, and high velocity 358 win loads.
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Try experimenting with slow, heavy projectiles. I did this with 6.5 CM before the hybrids were even a thing. I pushed a 150 projectile somewhere around 2450 fps out of a 16” gun. It went transonic around 900 and had better performance in the wind than lighter, faster projectiles pushing above 2600 fps. Plenty of people are putting down all kinds of animals with a similar set up in 8.6, including hogs.
I built a 6 lb 308 AR 10 16" barrel, titanium, carbon fiber, magnesium upper.
It's lighter than my AR 15s.
It does 2442 fps with 208 ELDM.
Beats carrying a heavy AR 10 in 8.6 Blkout for range and potential killing power.
155 gr 2875 fps with Sierra Palma.
168 ELDM, 2756 fps.
308 sub moa, cheap to shoot, huge variety of bullets, magazines, etc.
The 8.6 Blk is mainly a sub gun...thats why most buy it...it has little range potential with supers and the 3 twist. Poor BCs at low velocity.
I increased it super potential with 6.5 twist running 200 grs to 2600 fps in 24" bolt gun.
High velocity kills alot better for general use.
The standard 308 put more energy on target with supers, cause it has more powder capacity and new bullets with good BC for any reasonable range for hunting hog or other game.
My 16" 308 AR has 1200 yd upper turrent dial if needed 168 eldm at 2756 fps to go long for targets...not game.
It's lighter than my AR 15s.
It does 2442 fps with 208 ELDM.
Beats carrying a heavy AR 10 in 8.6 Blkout for range and potential killing power.
155 gr 2875 fps with Sierra Palma.
168 ELDM, 2756 fps.
308 sub moa, cheap to shoot, huge variety of bullets, magazines, etc.
The 8.6 Blk is mainly a sub gun...thats why most buy it...it has little range potential with supers and the 3 twist. Poor BCs at low velocity.
I increased it super potential with 6.5 twist running 200 grs to 2600 fps in 24" bolt gun.
High velocity kills alot better for general use.
The standard 308 put more energy on target with supers, cause it has more powder capacity and new bullets with good BC for any reasonable range for hunting hog or other game.
My 16" 308 AR has 1200 yd upper turrent dial if needed 168 eldm at 2756 fps to go long for targets...not game.
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The gas system is is pretty much tied to the barrel length.... with a few variations for specific purposes that allow for a bit of overlap.
What barrel length, how you intend to shoot that barrel, ...mostly subs? suppressed? Supers only? Adjustable gas block?
All this, helps determine the best gas system for you.
There are a lot of good barrel makers mentioned in these pages ...
No, Faxon the worst, No, BA.
No, 3 twist.. poor results with these from personal experience.
Start with 5 twist mostly subs to 6.5 twist best for dual purpose and accurate for best results with 8.6 Blk.
For subs only I do not even recommend the 8.6 Blkout . The 338 Spectre is super accurate with subs and supers of limited velocity. The 338 ARC imp has good sub accuracy and 8.6 super velocity when comparing 12 to 16 inch barrels ..
Plus it's a handy light AR 15!
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So, I tried my hand at resizing the 277 Fury to 308 Win......the issue I am having is that I cannot get the last section (the steel) to size down in my rcbs full length die. Anyone else had any issues?
No issues...the steel portion does not size down it's already slightly undersize for all chambers, that use standard 308 case heads....as all the cases you'd make out of the 6.8x51 hybrid case have the same basic head size.
Unless the case heads are oversize, & Ive never had one that was.
Do not use a Small base FL resizing die. Even though they too should have a bit of clearance on the steel.
Try a different FL 308 sizeing die .... a cheap Lee FL die, they work and are cheap to replace when sizing hybrid cases.
6.8x51 to 308 is the easiest to make. I mandrel up the neck to .308, then use the 308 FL sizing die.
Unless the case heads are oversize, & Ive never had one that was.
Do not use a Small base FL resizing die. Even though they too should have a bit of clearance on the steel.
Try a different FL 308 sizeing die .... a cheap Lee FL die, they work and are cheap to replace when sizing hybrid cases.
6.8x51 to 308 is the easiest to make. I mandrel up the neck to .308, then use the 308 FL sizing die.
I’m rethinking my subsonic 338 project. After my dogshit 3tw experience.
Do you think that an unmodified Rex 350gr bullet would fit a normal 338ARC prefit at 2.500-2.600 in a normal chamber ?
I’m about to order a 12.5in barrel for a dedicated subsonic bolt gun off a ARC CDG action but I can’t get over the fact that the 8.6BLK case is way too big for good consistent ignition and we don’t have any good bulky powder in the N110 burn range.
I have a spare Grendel bolt head for my action so I wouldn’t be too hard to sell my alpha 86 brass I previously bought and go with the 338 arc for the “cheap” factory ammo for plinking and just shoot the Rex 350 loaded at max AICS coal.
Quick load gives me 1111FPS at 2.500 with 10.5gr N110 and that’s a 99% case fill and 50K psi. In my experience with long range subsonic this is a way more optimal configuration than the 55% burn you’d get with 86BLK.
I’d go with a preferred barrel in 6tw
The 6 or 6.5 twist is the way to go with the 338 ARC.
If you are running a bolt gun you can extend the throat for longer COAL to give the 350 gr Maker more powder capacity and close to 100% case fill. The 350 is a lot of bullet for the 338 ARC ...but if throsted or bore riders incorporated you can run it to 1200 fps if ya want...putting more energy on target that the 3 twist 8.6 blkout cause it's limited to 1050 fps max or it may come apart before it reaches the target.
If suppressed the 3 twist should be held to 900 fps ....but the 6.5 twist will run them as fast as the little case
The first 350 Makers were slow unmodified and mag length for AR 15...no room left for powder.
The 350 gr bore rider is very consistent and accurate in 338 Spectre (10 mag case) and slighty larger 338 ARC case. They may look ridiculous but it works without throating the barrel for just one bullet.
I shoot supers in mine mostly, but subs are fun. And for accurate supers and subs the tiny cases rule...although the supers are not very fast, they are accurate.
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Yes, for me changing from the 3 twist to the 6.5 twist made a huge difference in accuracy and higher velocities.
Plus you can run every bullet even cheap jacked lead as fast as the case will allow without fear of the bullet blowing up and destroying your muzzle devices.
The 350 Maker will not be limited to 1050 fps max as with the 3 twist...
Here the 350 Maker hits 1800 fps in a 6.5 twist barrel and doesn't blow up inside the muzzle device but gets to the target.
Large bullet fragments found in the dirt...
If you ran a can in a 3 twist you should limit the 350 maker to around 900 to 950 fps to make sure it doesn't destroy your silencer.
With the 6.5 twist double the velocity no problem, and go from 700 ft/lbs at 950 fps to over 2500 ft/ lbs at 1800 fps ...if ya want, and better accuracy.
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Yes it was a bad idea ...plus an expensive lesson for me...my curiosity was actually a dangerous endeavor with the 3 twist.
The ridiculous 3 twist barrel was taken off and scrapped as a really bad idea..which I kinda suppected all along....but I had to try it, to find out for myself.
...But "never again!"...I totally agree with that statement.
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pasted from the other thread
I recently started reloading (less than 6 months) and started specifically because of the scarcity of 8.6 blackout ammunition. My interests are in short range work: to have the lowest possible shot signature, and the highest mobility and lethality I can get, the 12" Q Fix in 8.6BLK fit my use case.
I was aware of the 1:3 twist propaganda before I purchased my Fix this year; occasionally I do think I should have either waited until more barrels became available, or purchased something in 300 Blackout, but in that case I likely wouldn't have been interested in reloading and in retrospect, I would consider that a loss because reloading has turned out to be a very rewarding non-shooting shooting activity if you catch my meaning.
Anyway, I have my load development data on my website (which you can find in the About section of my profile). I actively update it from the range, shooting new loads every week or so. I would appreciate any feedback or advice about how to properly collect and analyze the data, I'm sorta just going by the ancient reloading threads I find on this forum, youtubes, and other tertiary sources.
Heres a summary of my learnings about subsonic 86 blackout at 1:3 twist rates:
Bullets:
- 300gr Sierra MatchKing HPBT (lead core) - Stopped for now, because I had one non-catastrophic baffle strike, I may return to copper jacketed bullets if I can reliably keep them subsonic. Non-catastrophic just means i took my suppressor to a gunsmith and we checked it out together, and he told me i was lucky that the jacket just barely struck the endcap and make a cosmetic dent in the exit hole. The baffles are undamaged, but will strill probably RMA it when I can, though, it shoots fine.
- 342gr Gorilla Punisher (solid copper) - Currently using, not afraid to push this to the supersonic barrier, but the bullets are expensive and scarce, i'm trying to keep these between 950fps and 1000fps.
Powder:
Vihtavuori N320 + 300gr SMK:
- 11.0-12.0gr range → 1055-1101 fps
- flew a little too close to the sun with this powder, will return to it later
CFE BLK + 300gr SMK:
- 16.5gr → 969 fps
- 17.0gr → 1035 fps
- seems to be the most promising powder for subsonic work in my environment. This powder also smells the best in the container.
Hodgdon LILGUN + 342gr Gorilla:
- 12.0-13.4gr range → 820-937 fps
- good subsonic performance, no complaints, but not sure if it's better than CFE BLK yet. and I see this powder in-stock everywhere.
I'll be testing CFE BLK loads with the 342gr bullets this week and i'll be testing the following bullets over the coming weeks:
- 285GR Barnes TSX, if these work well then they'll be thge best price at 1.16/bullet
- 250GR Fort Scott Munitions SBP1 (I hope these are safe in 1:3?? not 100% sure, but what else would fort scott munitions use in their factory ammos?)
- 250GR North Fork Solid Flat Nose, just look weird
any idea why the maker website says not to use CFE BLK for their 350gr bullets?
I recently started reloading (less than 6 months) and started specifically because of the scarcity of 8.6 blackout ammunition. My interests are in short range work: to have the lowest possible shot signature, and the highest mobility and lethality I can get, the 12" Q Fix in 8.6BLK fit my use case.
I was aware of the 1:3 twist propaganda before I purchased my Fix this year; occasionally I do think I should have either waited until more barrels became available, or purchased something in 300 Blackout, but in that case I likely wouldn't have been interested in reloading and in retrospect, I would consider that a loss because reloading has turned out to be a very rewarding non-shooting shooting activity if you catch my meaning.
Anyway, I have my load development data on my website (which you can find in the About section of my profile). I actively update it from the range, shooting new loads every week or so. I would appreciate any feedback or advice about how to properly collect and analyze the data, I'm sorta just going by the ancient reloading threads I find on this forum, youtubes, and other tertiary sources.
Heres a summary of my learnings about subsonic 86 blackout at 1:3 twist rates:
Bullets:
- 300gr Sierra MatchKing HPBT (lead core) - Stopped for now, because I had one non-catastrophic baffle strike, I may return to copper jacketed bullets if I can reliably keep them subsonic. Non-catastrophic just means i took my suppressor to a gunsmith and we checked it out together, and he told me i was lucky that the jacket just barely struck the endcap and make a cosmetic dent in the exit hole. The baffles are undamaged, but will strill probably RMA it when I can, though, it shoots fine.
- 342gr Gorilla Punisher (solid copper) - Currently using, not afraid to push this to the supersonic barrier, but the bullets are expensive and scarce, i'm trying to keep these between 950fps and 1000fps.
Powder:
Vihtavuori N320 + 300gr SMK:
- 11.0-12.0gr range → 1055-1101 fps
- flew a little too close to the sun with this powder, will return to it later
CFE BLK + 300gr SMK:
- 16.5gr → 969 fps
- 17.0gr → 1035 fps
- seems to be the most promising powder for subsonic work in my environment. This powder also smells the best in the container.
Hodgdon LILGUN + 342gr Gorilla:
- 12.0-13.4gr range → 820-937 fps
- good subsonic performance, no complaints, but not sure if it's better than CFE BLK yet. and I see this powder in-stock everywhere.
I'll be testing CFE BLK loads with the 342gr bullets this week and i'll be testing the following bullets over the coming weeks:
- 285GR Barnes TSX, if these work well then they'll be thge best price at 1.16/bullet
- 250GR Fort Scott Munitions SBP1 (I hope these are safe in 1:3?? not 100% sure, but what else would fort scott munitions use in their factory ammos?)
- 250GR North Fork Solid Flat Nose, just look weird
any idea why the maker website says not to use CFE BLK for their 350gr bullets?
Maker web site most likely has a warning on AA 1680 with their 350 gr bullet , because the velocity swings vary too much so as to get you into trouble with baffle strikes, as the velocity jumps from say 990 fps to 1100 fps with the same powder charge. Which happens with the 8.6 because of poor design for a sub only cartridge. Plus the 3 twist being even more limiting.
Do your self a favor and take off the 3 twist and toss it... I did.
Go to the 5 twist for sub only shooter or 6.5 twist for all around subs and supers.
As an example I shoot the 350 Maker at 1800 fps in my 6.5 twist with no problem of exploding.
I have warned against the 3 twist concept for yrs ...and people keep buying into the hype. It's much more expensive to shoot as one can shoot the cheap Speer jacketed bullets as fast as you want in a 6.5 twist fill the case and have accurate cheap supers.
The 350 gr make has a speed limit of 1000 fps max... in the 3 twist ...and the 1050 fps was recently added as a slight increase for the 350 gr with the 3 twist.
So you should shoot for 950 fps as your max with the 350 gr Maker and the 300 gr jacketed lead match bullets.
You have to heed warning velocity limits on Maker bullets...because the petals can blow off before it gets to the target, leaving you with a blunt FMJ instead of an expanding bullet even if you're lucky enough not to damage your muzzle device.
All Solid copper Barnes bullets will work in the 3 twist for a super load, the 160 gr on up.
If ya desire an Accurate sub gun get the AR 15 and the 338 Spectre or the 338 ARC...tiny capacity equals tight velocities, and a lot less vertical as the range increases.
Hey, curious if that velocity swings you mentioned with A1680 and 350 Maker is only specific to 1:3 twist? I have a 1:6.5 and haven’t noticed those large swings with my limited testing. It was 48F outside also. I’ve tested 300 SMK though in near 80F and haven’t seen those swings either. Thanks.
Also definitely agree with tossing the 1:3 barrel. It is what it is. Just move on.
Everything is better with a 6.5 twist barrel, better S/Ds , higher super velocities, and much better accuracy.
AA 1680 is harder to get consistent velocities out of with subs...even with a 6.5 twist and a bolt gun in 8.6 Blkout.
The 8.6 Blackout has too much case capacity for subs...half the case is empty of powder.
The easiest for me to get accurate and super low S/Ds for an auto loader in AR 15 was the 338 Spectre one powder for every bullet sub or super same powder.
Followed closely by the 338 ARC.
I changed the 8.6 Blk AR10 to 375 Raptor, I like that cartridge much better, not a particularly good sub caliber cause you need really heavy long bullets ti take up powder space then it's better. But it brings alot of close range power.
Here is another example of 1680 large velocity spreads vs Green Dot in the 375 Raptor shooting 350 gr SMK subs.
Fill the case up with H335 and back to single digit S/ Ds in the 375 Raptor for excellent accuracy. This gun likes the 235 gr Speer at 2550 fps..cheap and accurate.
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I appreciate it. Yeah, I’ve enjoyed checking out all your research with these other cartridges and agree. I’m already committed on this 8.6 but may change in the future. I like messing with new load development. I don’t wanna have to modify brass though more than sizing and cleaning.
With subs in the 8.6 try seating the bullets really deep to reduce case capacity on long heavy bullets ...Warning ...this will increase pressure very quickly....go slowly...and check accuracy, as you deepen the bullet into the case. I use QL to help with the pressure and velocity predictions.
The higher pressures will help get more complete and consistent powder burns, for lower S/Ds ...like mimicking the smaller 338 cases.
Even experimented with home machined 400 gr bullets in some of these 338 cases, then determine the COAL length to get enough powder, according to QL to keep em in the 1200 fps so one can adjusy the speed down, and have high percentage of case fill.
The higher pressures will help get more complete and consistent powder burns, for lower S/Ds ...like mimicking the smaller 338 cases.
Even experimented with home machined 400 gr bullets in some of these 338 cases, then determine the COAL length to get enough powder, according to QL to keep em in the 1200 fps so one can adjusy the speed down, and have high percentage of case fill.
thanks, appreciate the advice. I wouldn't mind comparing other twist rates, but feels like i'm kinda limited in my barrel options. it's either wait half a year for a 1:5 mostek barrel, or ditch 8.6 BLK and wait half a year for Q or Proof Research to get the 6.5CM and .308 barrels produced (which I definitely want but they're backordered to hell). Do you know where I could get a pre-fit 8.6BLK 1:6.5 barrel for my Q Fix? my searches failed to find anything.
In the meantime, I'm wanting to do my best to make the factory 1:3 twist barrel work for me; if it just takes strict adherence to a tight envelope of bullets/powders/parts then that's not _so_ bad as a niche novelty rifle. I accept that I will probably have to find a different hog nuking rifle long term, but still no ragrets
The Raptor is what really caught my attention. Formed is preferred. I guess, realistically, if it could be “cut down” on a Giraud trimmer easily I’d be ok. I haven’t chopped off brass and probably prefer not to if possible. I’ll need to go back and look at all that. It’s been a minute and don’t wanna derail this thread.
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