8.6 Blk reloading info

45-90 · Aug 13, 2024

wgranvilleb said:
@45-90: thanks for the very informative follow-up, and your three part series.

Your experience with the 350 gr Makers projectiles is very interesting shooting 8.6 BO subsonic with 1:6.5" twist, and experiencing the lack of opening. I have attached a picture of recovered projectiles of the same round from earlier this year shooting subsonic at 300 yards with a Q Fix 1:3" barrel. The projectile on the left hit a steel gong (note the steep angle of impact) and the second is recovered from the dirt birm at 300 yards.

It is interesting the subsonic projectiles open with 1:3" twist, yet failed to open with 1:6.5" twist.

Regarding the supersonics, totally agree that the aggressive 1:3" twist rate limits velocity. Mos-tek is now offering 8.6 barrels with twist rates of 1:3", 1:5", and 1:6.5". Their initial impression is the 1:5" may represent a sweet spot to maintain energy and accuracy with subs, yet raise the supersonic velocity ceiling imposed by the 1:3". Another rabbit hole. . .

Regarding the inexpensive plinking ammo you found, do you think it will stand up to the 1:3" twist rate? Where are you sourcing it at that price?

Thanks for all of the follow-up, all greatly appreciated.

I don't think it's the twist rate, as I also have a 3 twist to try them in.
I think it's the medium, mostly gravel.
If I shot them in mud or ballistics gel they would open the same, regardless of twist.
I was concerned about how they perform on animals, not gravel, and was concerned about hide and heavy bone, bending them first, causing them not to open up.

Since I have both twist rates, I should be able to perform tests on that very subject.
Both subsonic, fired into the same soft medium, just the 3 twist vs the 6.5 twist.
I expect no difference...but we'll see.
Been wrong before...
So far the 6.5 twist has all the advantages, subs, or supers, with any bullet, better accuracy, can't blow up bullets inside the muzzle device, and more speed, totally versatile with any bullet.

I have ran fmj 250 gr in my 3 twist, if I remember correctly to 1600 fps and still stayed together.
I have not tried this 272 gr bullet in the 3 twist...as I gave up on it for my purposes, but others who only run subs, like the 3 twist. But I felt the 8.6 was a good cartridge if given a slower twist barrel.
That's what's been working for me...so I just report on what I observe...you decide if it's right for you.

I purchased the 272 gr 338 fmj from American Reloading $30 per hundred delivered on sale just yesterday, cause I liked the accuracy I got for cheap plinking loads on a prior purchase.
Here is a pic of the bullets.
And a Barnes super opened up nicely in soft medium.
I don't check mushroom performance much, as I use the 8.6 for target and plinking, not hunting.
So 8.6 Blk with 300 gr match bullets at almost 2000 fps will actually be a LR plinker capable of 1000 yd hits.
Different strokes for different folks.

45-90 · Aug 13, 2024

I don't think it's the twist rate. I think it's the medium the bullet is fired in.
I believe the expansion will be close to the same.
I have a 3 twist and a 6.5 twist to check that theory in when shot it soft medium or ballistics gel.
We'll see.
I've been wrong before.
The reasoning is because I shot them in gravel, which tears up everything.
I used a grave pit as I was shooting a few Armor piercing in the 510 whisper, these in the 50BMG are capable of penetrating 3/4" steel at 100 yds.
Look at how messed up the soft steel jacketed FMJs are, then look at the 3 recovered armor piercing, even broke one on half ...that's gravel.
Put them in soft medium like ballistics gel and none would be deformed at all...
Reason why I don't believe it's twist rate but impact with gravel.
I was concerned about those who hunt with the 8.6 as to whether or not these would open if point was plugged with hide, fat, deform on bone, etc so as not to open up, as pictured in the ballistics gel experiments.
Cleaning the bolt guns in 8.6 and 510 whisper, and tumbling a bunch of 8.6 cases. So in a few days I'll see if I can catch a few in soft medium and compare 3 twist to 6.5 twist both subs. Maybe even shoot the 3 twist in the gravel.

SigSauerM7 · Aug 15, 2024

Nice. Looks good. Lots of good data .

45-90 · Aug 19, 2024

So I completed a test with 6.5 Twist and 350 Maker bullets.
They do indeed open up in the 6.5 twist. But it may be delayed a bit when compared to the 3 twist.
You can adjust the velocity up to 1600 fps to get some real power, with the muzzle device attached and good accurscy, in the 6.5 twist....not limited to 1050 fps as in the 3 twist.
Accuracy, the 3 twist is horrible...group sizes were 3 and 1/3 times larger with the 3 twist with the 350 gr Maker. Some even greater, like 6 and 1/2 times larger!
Reminded me why I gave up on the Faxon rough barreled 3 twist. It just as waste of ammo.
I enjoyed the AR platform, but will do no more shooting with this barrel.
The 6.5 twist and 350 gr Makerl...looking through the back, as the bullet expanded in this jug of water.
Exit wound in wet paper shows expanded bullet with petals still present.
These 350 Maker were not caught in full bloom. They open up and had a huge cavity in a burned log, then lose the petals and penetrate for ever,.. it seems. Stopped it with armor plate, glanced off the plate, and dug into the ground. Took a shovel to find it.
How fast they open is adjustabe by velocity to only 1050 fps with the 3 twist. But do not open at around 750 or maybe 800 fps depending on medium impacted. Steel would be different, gravel was different...so it depends...
I'm only testing these and do not plan to hunt with the 8.6 Blackout.
The performance varies, and is somewhat adjustable, but it's a close range bullet as the velocity changes the performance changes.
So if ya find a velocity and range it works good in, on the animal you hunt, keep your range limited.
Not that it won't kill if it doesn't expand, but works a lot better if it does.
I bought 5 boxes of these 350 Maker bullets and fired almost 2 boxes on testing. Is it a good hunting bullet? Who knows? I haven't killed anything with it.
But it will penetrate, after the petals break off...
And the accuracy of the Faxon 3 twist ...if ya aim at a hogs head and hit him in the lower jaw at 70 yds...that is about my accuracy with the Faxon 3 twist barrel, so expanding won't kill him....but the 6.5 twist will put the bullet very close to where you aim, 350 Maker, or almost any other, in subsonic mode, plus you have excellent supersonic capabilities with any lead bullet guaranteed to dump a hog, economically.
After today the Faxon 3 twist is definitely retired...I have better things to do, than waste ammo, with this horribly inaccurate barrel.
But if you love your 3 twist, keep on using it. Other brands might be a bit more accurate.

wgranvilleb · Aug 19, 2024

@45-90 : Thanks for the thorough testing and follow-up. All of your hard work is greatly appreciated.

45-90 · Aug 20, 2024

Well the Faxon 3 twist barreled 8.6 AR, is no more...
Took the gun apart, saved the good stuff and discarded the barrel.
If I build another AR in 8.6 it will be a 6.5 twist barrel.

@xedentlyprone · Aug 21, 2024

I'm looking to get an AR load recommendation(s) for 16" faxon 1:3 twist using 270 eldx. Super and or sub.

DRWilson · Aug 21, 2024

@xedentlyprone said:
I'm looking to get an AR load recommendation(s) for 16" faxon 1:3 twist using 270 eldx. Super and or sub.

If you can, run a 6.5 twist and you can get that bullet humming. Not sure the bullet can get going fast enough to expand with the speeds a 3 twist can generate. I’m not sure a 6.5 twist will be able to expand that bullet either. Someone probably has better knowledge on that.

45-90 · Aug 21, 2024

The 3 twist is very limited, to hunt you need the specialty bullets from folks like Maker, for 1050 fps max velocity.
Or all copper bullets from people like Barnes for faster supersonic loads....but most won't go fast enough to open up if very heavy, and range is still short.

I ran the lead 285 gr ELDM in my 3 twist, it blew up around 30 yds, at just 1400 fps.
According to Hornady it needs 2400 to 3200 fps muzzle velocity in conventional rifling like 10 to 8 twist to perform, 0 to 400 yds in a hunting situation...but might deform a little down to 1600 fps. Giving it long range potential in a conventional rifle...not the 3 twist.
It can be shot in a 3 twist around 1200 fps, maybe...but might as well shoot it at 1050 fps, to be safe, in the 3 twist...all loads with lead and Maker should be in that range...max 1050 fps. It's basically a subsonic round.
I like the Barnes 160 gr for velocity but no copper bullets were accurate in my 3 twist, plus it slows down fast...making it a short range rifle.
Change to the 6.5 twist, long barrel, bolt gun and the 270 gr is good for 2000 fps...its good for hunting to 500 yds, on elk in the high desert 4200 ft elevation...according to Hornadys minimum 1600 fps and 1600 ft/ lbs on impact...but I wouldn't do that. But 300 yards would be easy...And why I personally quit using the 3 twist.

Your 3 twist 270 gr ELDX load would be 15.0 gr AA 1680, for function, 1050 to 1100 fps...maybe, it's a Faxon barrel my 3 twist was rough as hell, torn and galled rifling...that helps tear up bullet jackets causing failures...it wil be target shootable but not a hunting bullet, for the 3 twist ...it's too slow to perform, as its manufactured for the high velocity of the 338 magnums.

Chronograph it to be sure, and take off your muzzle device....or experience the bullet blow up in your muzzle device, destroying it, and your chronograph bayonet. I spent considerable time and money on the 3 twist...it's very specialized, with expensive special bullets for hunting subsonic, at close range...it's main goal...IMO.

wgranvilleb · Aug 21, 2024

@xedentlyprone said:
I'm looking to get an AR load recommendation(s) for 16" faxon 1:3 twist using 270 eldx. Super and or sub.

Fully agree with @45-90 post in #906. He has considerable reloading experience in general, and especially in this area (and unfortunately bad luck with Faxon barrels).

Q LLC, who developed this round, recommends only using solid copper or bonded projectiles for the 1:3" twist. Just assume most anything else will spin apart as soon as it exits the barrel.

Two functional areas to consider:
- rifle: cycling in an AR platform (non-issue in a bolt gun)
- projectile: minimum velocity for proper function (expansion)

If you haven't already, I suggest you refer to an earlier post in this thread #893 for a starting point for loading data. Additionally, in order to load for this round, a chronograph is nearly indispensable.

I agree with @45-90 in that the eldx projectile is not suitable for the 1:3" twist and requires velocity for function which is beyond scope of the 8.6 BO. Furthermore, and to emphasize what @45-90 has previously stated, this projectile will likely be dangerous and self-destruct upon exit from the barrel. IMHO, the 275 gr weight is much too heavy for (practical) supersonic loading.

My opinion, FWIW, is to select projectiles that are more suitable for their anticipated roles for the 1:3" twist which is a highly specialized environment.
- Subsonic:
- the 300 gr SMK was used for primary load development and I did not experience any difficulties with projectile instability. As mentioned previously, Maker manufactures 300 gr and 350 gr solid copper projectiles which are specifically designed for 1:3" twist subsonic loads. (Note: the 350 gr projectile only loses ~100 fps at 300 yards).
- Supersonic:
- 160 gr Barnes TTSX was used during my load development as the lightest available projectile to determine a maximum velocity limit for projectile function and to guesstimate maximum useable range (ballpark 150 yd - 175 yd (max)).
- 220 gr Maker - designed for 1:3" to operate in the 1,500 fps - 1,900 fps velocity range and probably 125 yd - 150 yd range. IMHO, this is the heaviest projectile weight I would be comfortable using for (practical) supersonic applications.

In summary, the 1:3" twist is a challenging and specialized environment. An emphasis on safety is even more important than the usual levels when loading for more conventional twist rates. Proceed carefully . . .

45-90 · Aug 21, 2024

I did extensive tests on the 3 twist....
Here is an example:
My 16" faxon 3 twist one of their recommended loads that to months to get removed from their site.
A lead supersonic 225 gr bullet out of a 3 twist...will not kill a rabbit at 10 yards!
Notice the muzzle has no muzzle device, (I learned the hard way) and it's fired 2 feet from the opening of a large box.
The bullet comes completely apart as soon as it leaves the confines of the barrel.
Bullet fragments covering the top bottom and sides of the big box.
Back up to 8 feet and the outside of the box is hit with bullet shrapnel, jacket and lead pieces.
The air is full of lead dust....difficult and dangerous to breathe.
I fired 5 or 6 in rapid sucession in the dirt at 10 feet, and the air was poisonous, had to back off.
The 3 twist can be very dangerous.
I did these experiments so you don't have to. Do not have anyone beside you if you decide to try this as some fragments exit at 90° and will injure a person next to you. If you leave a muzzle brake on, the bullet fragments and break fragments can come back at you.
I experience that on the first Faxon recommended lead load...I was lucky it only cased a few hundred dollars in damage, destroyed the break and magnetospeed bayonet.
Be safe get a chronograph, keep velocities in the 1050 fps range and test without a muzzle device...or have some stainless steel break pieces, and deflected bullet fragments, come back to your face and chest.
It will be a WTF moment...
If you like your 3 twist I'd strongly suggest you stay inside the speed limit of 1050 fps, and even 900 to 950 fps for suppressor.

Now take the same bullet but 200 gr instead of 225 gr put it in a bolt gun 6.5 twist with a long barrel...and ya have a dual purpose cartridge.
Cheap 200 gr Speer over 2500 fps... with accuracy.
Or a one hundred yard ladder test with 285 ELDM, And 300 gr match bullets one same target...you can see the bullets grouping together as the velocity increases.
Cause one can go heavy super loads with out fear of bullet blow up, huge gains in bullet energy are available 2850 ft/lbs with the 200 gr Speer on sale for 30 cents, or 2790 ft/lbs for the 160 Barnes, or 2590 ft/lbs for the 300 gr Berger, and 2200 ft/lbs for the 350 Maker...
Take the 300 Berger to 1000 yds 1244 fps remaining velocity with 1032 ft/bs. Drop 53.8 MOA wind 72 inches of drift in a 10 mph cross wind ...that's doable.
I only harp on this for safety for those who like their 3 twist...and there's another option to consider, a slower twist...with the 6.5 twist, giving the option of a real dual purpose cartridge. This is just my journey with the 8.6 Blackout, all it's problems and what I consider a solution to them.

@xedentlyprone · Aug 21, 2024

Great info! Gonna have to do more reading and thinking on this now.

Also I'm testing function in an st 8.6 and with fort scott subs tui im getting failure on to eject ...to me I think short stroke based on case particularly exiting and jamming since I had the gas all the way up and ran it down with dame issue. Also thought my jp buffer with law folding extension may be an issue with factory spring so was going to change up the buffer weights and or spring

Dogtown · Aug 21, 2024

This thread made me go with the 1:6.5…thanks

45-90 · Aug 21, 2024

@xedentlyprone said:
Great info! Gonna have to do more reading and thinking on this now.

Also I'm testing function in an st 8.6 and with fort scott subs tui im getting failure on to eject ...to me I think short stroke based on case particularly exiting and jamming since I had the gas all the way up and ran it down with dame issue. Also thought my jp buffer with law folding extension may be an issue with factory spring so was going to change up the buffer weights and or spring

If you're gonna shoot the 8.6 Blackout, you should be a reloader, with a chronograph.
The 16" Faxon has carbine gas, with a .106" dia gas port, works with AA1680 powder, even down to 800 fps. With standard carbine buffer and spring,..nothing special needed.
You can not depend on others to make ammo for this 8.6 especially 3 twist, and have it work for you, because of all the variations in barrel length, chambers, rough rifling, gas port size, gas lentths etc.
It's mostly disappointing in function and accuracy...from the reports I've seen.
Even if a factory ammo works for a few boxes a slight reduction change in powder charge could mean a malfunction. They have to keep ammo on the low side so the bullets don't blow up on most and subs...except Barnes, and Hornady solid copper types for high velocity.

DRWilson · Aug 31, 2024

I am SOLD on my 6.5 twist 8" Mostek Barrel for my AR platform setup. It's more accurate for me. I zeroed and shot it for the first time today and I immediately noticed the difference in accuracy. I was finally stacking bullets and that was lacking in my 3 twist barrel. I hope to shoot my 12" bolt 6.5 twist Mostek barrel tomorrow and that will be my first time shooting that one. My previous barrel was a Faxon and my grouping didn't exit. I had a 20 moa groups at 100 yds .It was nuts. So far the AR will be subs only and my bolt will be supers.

DRWilson · Sep 1, 2024

Okay. I took the bolt gun to the range and zeroed my 6.5 twist barrel. Geez! I must have had a bad Faxon because this is now a sub MOA round with supers. I am shooting Barnes 225gr ttsx and the bullet gets full expansion at 1800fps and 1.7x expansion at 1600fps. I will be working up my own loads to maximize my expansion distance. For factor loads, I am at 1992fps. I am hoping for more with my Alpha Brass running a slightly higher pressure. Wish me luck!

GregP42 · Sep 8, 2024

DRWilson said:
I am SOLD on my 6.5 twist 8" Mostek Barrel for my AR platform setup. It's more accurate for me. I zeroed and shot it for the first time today and I immediately noticed the difference in accuracy. I was finally stacking bullets and that was lacking in my 3 twist barrel. I hope to shoot my 12" bolt 6.5 twist Mostek barrel tomorrow and that will be my first time shooting that one. My previous barrel was a Faxon and my grouping didn't exit. I had a 20 moa groups at 100 yds .It was nuts. So far the AR will be subs only and my bolt will be supers.

I went to Mos-Tek's website, they show a 1-3 or a 1-5 for the bolt action barrels, do you have to call them to get the 1-6.5?

Greg

wgranvilleb · Sep 8, 2024

GregP42 said:
I went to Mos-Tek's website, they show a 1-3 or a 1-5 for the bolt action barrels, do you have to call them to get the 1-6.5?

Greg

Greg,
You can order it online. There is a build page with a list of options on their website.
(Barrel length, twist rate, muzzle finish (shoulder and thread pitch), chamber collar, cryo treatment, coating, etc.)

The 1:6.5" is if you are oriented more towards supersonic applications, the 1:3" for subsonic applications, and Mos-Tec claims they have found a sweet spot between the two with the 1:5" twist for a balance between the two extremes.

You will need to decide how you plan to use it and choose accordingly.
Be aware, there is a 25 week lead time.

DRWilson · Sep 8, 2024

GregP42 said:
I went to Mos-Tek's website, they show a 1-3 or a 1-5 for the bolt action barrels, do you have to call them to get the 1-6.5?

Greg

It was on their site when I ordered. I’d call them or email. They usually get back in a day or two from my experience. But they still make the 6.5 twist… that I know. I have really appreciated working with them.

MSBRPT · Sep 10, 2024

Received a 6.5 twist barrel from Mos-Tek for the Fix. Quality looked better than the Q 1:3 barrel when I scoped it. Shot it for the first time today with random hand loads and Gorilla subsonics. Muzzle velocities seemed a lot more consistent than the 1:3.

I couldn’t get groups on paper. Went from a dirty zero on a 66% IPSC at 185 yards to paper before I got a squib before grouping. I was able to knock it out. The load was a SRP using BR4s. None of the powder burned, which got me thinking if SRPs aren’t suitable for subsonics where case fill is pretty low. From what I understand LRPs have a lower rate of failing to ignite. Some background, just swapped the barrel from 6.5 CM and shot hundreds of hand loads using SRPs without this issue. Could’ve just been a bad primer, not sure. Looking for insight before I get another squib I can’t knock out on my own.

45-90 · Sep 11, 2024

MSBRPT said:
Received a 6.5 twist barrel from Mos-Tek for the Fix. Quality looked better than the Q 1:3 barrel when I scoped it. Shot it for the first time today with random hand loads and Gorilla subsonics. Muzzle velocities seemed a lot more consistent than the 1:3.

I couldn’t get groups on paper. Went from a dirty zero on a 66% IPSC at 185 yards to paper before I got a squib before grouping. I was able to knock it out. The load was a SRP using BR4s. None of the powder burned, which got me thinking if SRPs aren’t suitable for subsonics where case fill is pretty low. From what I understand LRPs have a lower rate of failing to ignite. Some background, just swapped the barrel from 6.5 CM and shot hundreds of hand loads using SRPs without this issue. Could’ve just been a bad primer, not sure. Looking for insight before I get another squib I can’t knock out on my own.

I don't use SRP in 8.6 loads....but have used them in 308, & 450 Bushmaster...where fairly large powder charges are used.
Did a small test one time with both SRP and LRP in the 308 with heavy 230 gr bullets in a 9 twist 22" bolt gun. The LRP were more consistent in velocity, had better accuracy, and about 40 fps faster with the same weight powder charge. So these days I tend to use LRP...although I still have several boxes of Lapua SRP in 308 and 6.5 CM. I will not purchase any more, so that's where I stand on SRP in larger cases.

But I did have a very similar problem where no powder ignition happened. It was not the primer...It was small bullet diameter.
It takes a lot of resistance to build pressure.....pressure resistance causes the powder to burn. And why high pressure rounds burn cleaner.
if all the bullets are correct caliber for the barrel, like .338" and not a .333" thrown in then its likely one bad primer, rare but it does happen.
To get better ignition a smaller neck diameter die can help...along with a Lee factory crimp die...

wgranvilleb · Sep 11, 2024

MSBRPT said:
Received a 6.5 twist barrel from Mos-Tek for the Fix. Quality looked better than the Q 1:3 barrel when I scoped it. Shot it for the first time today with random hand loads and Gorilla subsonics. Muzzle velocities seemed a lot more consistent than the 1:3.

I couldn’t get groups on paper. Went from a dirty zero on a 66% IPSC at 185 yards to paper before I got a squib before grouping. I was able to knock it out. The load was a SRP using BR4s. None of the powder burned, which got me thinking if SRPs aren’t suitable for subsonics where case fill is pretty low. From what I understand LRPs have a lower rate of failing to ignite. Some background, just swapped the barrel from 6.5 CM and shot hundreds of hand loads using SRPs without this issue. Could’ve just been a bad primer, not sure. Looking for insight before I get another squib I can’t knock out on my own.

Thanks for your initial feedback with the new barrel. Additional follow-up as you gain experience will be appreciated.

Regarding the primers, I have only used LRPs and have had no issues.

Regarding the zero and grouping . . . when starting out in a new environment such as new barrel, projectile, charges, scope, etc., I eventually acquiesced to the more classical approach of large paper at short distances (~50 yds) to verify I'm in the ballpark before pushing out to distance. IMHO, the few initial shots up close save time later.

Please keep us apprised as you progress.

MSBRPT · Sep 11, 2024

wgranvilleb said:
Thanks for your initial feedback with the new barrel. Additional follow-up as you gain experience will be appreciated.

Regarding the primers, I have only used LRPs and have had no issues.

Regarding the zero and grouping . . . when starting out in a new environment such as new barrel, projectile, charges, scope, etc., I eventually acquiesced to the more classical approach of large paper at short distances (~50 yds) to verify I'm in the ballpark before pushing out to distance. IMHO, the few initial shots up close save time later.

Please keep us apprised as you progress.

Couldn’t group yesterday because the second round on paper squibed. Went back today and shot a 6 round group. First three rounds stacked pretty close together. The following 3 opened up slightly with the 6th being a possible flyer, ckye pod feet slipped on concrete bench top. With the flyer the group is just under 1.5 MOA. Without it, it’s .8 MOA. I was able to pick up 10 shots (yesterday’s shots and todays) from the load which was 11 grains of Lil Gun, BR4s, converted alpha 6 GT brass and 250 grain lapua scenars seated at 2.7” COAL. Average MV was 979 fps with a SD of 11.9. I feel a lot more confident in this barrel as far as accuracy and consistency goes than the 1:3 so far. Being able to break subsonic without damaging equipment or worse is nice too.

As for the squibs, I had a few more today. When chambering the cartridge I felt some resistance. Fired and nothing happened. Same thing I experienced yesterday with none of the powder being burnt. Popped out the round which is getting lodged where the lands start. The following squib, once I felt more resistance than normal I pulled the bolt back before even trying to lock the bolt down. The round still got lodged. After cleaning Lil Gun out of the chamber and barrel for the second time I called it. All sized brass, neck wall thicknesses and loaded cartridges get checked with a gauge and are within spec. This happened only with the scenars and not with 350 grain makers. Neck tension is set to .002” under for all cartridges. I haven’t measured distance to the lands in the 6.5 barrel. Once I figure out the cause I’ll give an update.
Update:
I measured distance to the lands and CBTO on the handloads. I got a difference of .017”. It seems the lands are closer in the 6.5 twist barrel than pre-fits from Q. I believe seating the bullet deeper will remedy the stuck bullets. CBTO on hand loads with 350 grain makers are under the measurement to the lands.

MSBRPT · Sep 11, 2024

I sat the scenars to 1.99” CBTO and this fixed my squib issue. The lands were pulling the bullets when locking the bolt. No pressure and no ignition. The Mos-Tek barrel has a shorter distance to the lands. I’m very happy with the barrel. Group is under 1” and MV is really consistent. Distance was 100m.

45-90 · Sep 11, 2024

MSBRPT said:
I sat the scenars to 1.99” CBTO and this fixed my squib issue. The lands were pulling the bullets when locking the bolt. No pressure and no ignition. The Mos-Tek barrel has a shorter distance to the lands. I’m very happy with the barrel. Group is under 1” and MV is really consistent. Distance was 100m.

Also make sure you're not oversizing the brass with the new barrel. If the COAL is different on this chamber. The headspace may be different also, allowing excess headspace..check your fired cases (preferably a full power load) against your FL sized cases.
Pushing the case too far into the chamber with headspace inconsistencies will cause a few miss fires as described, or "click" when the trigger is pulled, with the bullet jammed into the rifling the bullet and powder are left in the barrel.
One can hard jam cases in fireforming wildcats to fill out 40° shoulders, but the case closes on the bolt with resistance in rough forming....or closes on resistance with the false shoulder method.
The primer always goes off, fire forming the case....is why I mentioned checking the fired case headspace against the FLsized case before continuing...with measuring tools. Then adjust the die to the chamber.

DRWilson · Oct 4, 2024

I am finished with my load development for the 6.5 twist 8.6Blk in 12" and 8". I also have a 5 twist, 16" on order. All Mostek barrels. This rifle is now what I was hoping and expected. It is accurate! I can shoot 225gr out of my bolt gun at 2100fps and it is an MOA rifle at 100yrds. I can shoot 350gr subs out of the 8" at 1025fps with moa accuracy which is really surprising me but I'll take it. I can't stress enough how happy I am with this sense making the switch. For me, it makes this rifle worth shooting and fun again. Good luck everyone with their builds and load development! And thank you for sharing your notes and process!

225 ttsx, 2.74 COAL, 37gr H335
350Gr Maker, 2.74 COAL, 16gr H110

Steven.Blk · Oct 5, 2024

I just got 100 of the new starline LRP 8.6 brass. Has anyone worked with these yet. I cannot imagine them being too much different that my converted BHA and Hornady 6.5 cm brass

DRWilson · Oct 5, 2024

Steven.Blk said:
I just got 100 of the new starline LRP 8.6 brass. Has anyone worked with these yet. I cannot imagine them being too much different that my converted BHA and Hornady 6.5 cm brass

I am going to have to check that out!

wgranvilleb · Oct 5, 2024

Regarding case reforming:
What I have found is, it is all (mostly) about the case neck thickness and trueing the surfaces. I've been converting different cases of all types and as the body wall becomes the 8.6 neck, it requires neck turning inside and out.

Tools purchased for reforming brass to 8.6:
- Hornady case neck turner for outside trimming
- L.E. Wilson case neck reamer, now offered in 8.6/.338
- L.E. Wilson mandrel die
- L.E. Wilson depriming die
- Sheridan case gauge (cut away style) is indispensable
- ball micrometer for measuring case neck thickness

After reforming (very) old Lake City brass from .30-'06 to 8.6, I found the 'neck walls' approaching .018" or even more. So, I purchased the Hornady (outside) neck trimmer. There is a bit of a learning curve, but take small steps, lube the mandrel frequently, and keep the rpms low and feed rate slow, and a decent result can be obtained. However, initially, I noticed I had way more runout than what seemed reasonable. So, I purchased the L.E. Wilson (inside) neck reamer and was surprised by how irregular the inside surface is. Before neck reaming, I use the L.E. Wilson mandrel die to expand to a known diameter (an easier approach than using the resizing die ball).

@45-90 has posted in this thread his process for 8.6 case forming. I have modified his approach a bit since I don't have the skills/access to the machine tools at his disposal.

My process for brass forming to 8.6 BO:
- Deprime the case
- I use the L.E. Wilson depriming die.
- Cut parent case ~.030" longer than the 'trim to' length.
- for this, I use the Harbor Freight 2" cut-off saw and a jig on Etsy from 3D designs.
- Anneal the case in the region of the 'to be' case neck.
- Set-up annealer using an already formed piece of brass
- Reform case to 8.6
- Mandrel the case mouth up to .338 (L.E. Wilson mandrel die)
- Neck ream (inside) case neck with L.E. Wilson reamer
- Neck turn outside case neck (Hornady case neck turner)
- practice on some cases before working with the 'good brass'.
- frequent lube on neck turning mandrel, low rpm and small trim steps
- looking to achieve .012" - .013" final thickness
- Final case trim to 'trim to' length
- final tumbling (optional)
- need to remove lube from inside of the case neck to not attract powder when loading
- Chamfer inside / outside case mouth

I hope this helps . . .

45-90 · Oct 5, 2024

Good news, for 8.6 Blackout reloaders.
Starline is usually pretty good brass, at a reasonable price. Should take similar pressures as most converted brass.
Just weigh the H2O volume to make sure it's pretty close. Then test it to see how it handles pressure in the super sonic loads.
Most sub loads are way under pressure unless a fast powder is introduced.
I think the LR primer is mostly a plus, cause my super loads will reach over 40 grs of ball which is harder to ignite.
It would have to be tested individually on easy to ignite powders, but a case half full or less, it would seem that a large primer flame would be likely to give better ignition across the powder laying in a horizontal or next to the bullet position as the rifle is moved into firing position, which has actually shown to cause large velocity variations, and the case fill near 100% is always desired, in most tests and in theory.

Move the rifle up, down, and horizontally powder shifts in the case, so another variation to contend with.

45-90 · Oct 12, 2024

That's not uncommon to go up a fraction of a grain in the powder charge and have the same or even a drop in velocity.

A lot of factors contribute to this, subs can be more difficult depending on case capacity, low pressure allowing powders to be less efficient, powder position in case, and to lesser degree no exact weight powder charge contains the exact same amount of energy.
Then that energy can be transferred to heat energy, instead of velocity, if all the bullets are not dimensionally perfectly the same, in the same position in the chamber. Plus case capacities not identical, all these variations, and probably 100 more contribute to velocity variations.

That's why many do all the case prep, weighing, annealing, etc, with super accurate powder scales, to move those velocity spreads closer. A personal choice.
I usually do only what's necessary to get to an acceptable place for the particular endeavor, but sometimes it requires alot of those procedures I didn't plan on doing.

So one could weight out 5 cases with the same capacity, same neck tension, annealed, checked for runout, bullet weighing and inspection...you know the drill and see if you get an improvement...sometimes ya won't, or the small improvement is not worth the effort.

I would try 16.3 grs and see how much velocity variation there is in 5 shots, and 1051 fps covers ya down to 0° according to your chart...depending on how temperature sensitive the powder is.

Chipster697 · Oct 18, 2024

I only have 100 Hornday cases I bought from Q and 80 from once fired Gorilla ammo. Should I step up and pay $1.15/case from Q or just go to Starline for 77 cents a piece?

With the 338 ARC media blitz, I’m afraid this is the last commercial 8.6 Blackout brass we’ll see.

DRWilson · Oct 18, 2024

If you are going pay 1$ for brass, go with Alpha Brass. But the starline brass will but just fine and more then adequate for an AR platform.

Chipster697 · Oct 18, 2024

DRWilson said:
If you are going pay 1$ for brass, go with Alpha Brass. But the starline brass will but just fine and more then adequate for an AR platform.

Thanks! I didn’t realize Alpha even made 8.6 BO brass and I’ll take their quality over Hornady any day of the week.

I have a Fix rifle so the Alpha brass probably makes the most sense. Might grab 250 of the Starline though just as a reserve and for plinking.

db2000 · Oct 18, 2024

Chipster697 said:
Thanks! I didn’t realize Alpha even made 8.6 BO brass and I’ll take their quality over Hornady any day of the week.

I have a Fix rifle so the Alpha brass probably makes the most sense. Might grab 250 of the Starline though just as a reserve and for plinking.

I use a few Q and Alpha mostly what limited amount I’ve shot mine.

Steven.Blk · Oct 19, 2024

Chipster697 said:
I only have 100 Hornday cases I bought from Q and 80 from once fired Gorilla ammo. Should I step up and pay $1.15/case from Q or just go to Starline for 77 cents a piece?

With the 338 ARC media blitz, I’m afraid this is the last commercial 8.6 Blackout brass we’ll see.

I don't see 8.6 being displaced by 338 arc.

45-90 · Oct 19, 2024

Chipster697 said:
I only have 100 Hornday cases I bought from Q and 80 from once fired Gorilla ammo. Should I step up and pay $1.15/case from Q or just go to Starline for 77 cents a piece?

With the 338 ARC media blitz, I’m afraid this is the last commercial 8.6 Blackout brass we’ll see.

I checked into the 338 ARC even made a die to mock up a case. Its almost the same as the 338 Spectre, just .030" longer with it's shortened 6 mm ARC case.
Will hold around 29 to 30 grs of water.
It's the AR 15 platform, it will run at much higher pressures taking the almost 52,000 max psi to the grendel bolt.
So powder burns should be more consistent, smaller velocity deviations, better sub accuracy with quality components.
With a 1-8 twist it will shoot any lead bullet, but can be a bit slow to open up speciality bullets, and go with the Maker 338 Spectre bullet for proper expansion...maybe.
The down sides.
it will be limited to 300 gr bullets for subs, to fit the AR mag, the 350 Maker may fit on a longer or cut out mag...but velocity may be too low to expand.
Feeding may be problematic with Grendel mags, and barrel extensions need modified to fit .338" bullets.
Supers? Will be very limited and not very super like 160 gr Maker for the 338 Spectre.
It appears to basically be a one trick pony...subsonic, as most conventional lead or copper bullets will never reach expansion speed, at its max pressure super sonic speed....they'd just be good for plinking and target.
But it does have a place, for subsonic almost exclusively in an AR 15.
But it's not cheap like a 300 Blk with bulk 147 fmj to just plink away.
I'd be interested to see how accurate I could get the subs to shoot, not for hunting but for target. That's my interest in it.
You'd have to decide if it's limitations fit with your shooting endeavors.
As you can see I'm already on it, even lined up my load data...the case is made from 6.5 Grendel...but 7.62x39 Starline are cheap. Manson has reamers ready to go.
But a quality AR barrel would be nice.
Don't really want to machine an AR barrel from a fast twist blank for this dinky little cartridge, just to maximize accuracy....I'd probably choose the 6.5 twist, since it's subs. Even though for targets the 8 twist is calculated to work.

wgranvilleb · Oct 20, 2024

Mike6158 said:
I'm one of those people that have a very accurate scale. I recently added a A&D scale with an autotrickler V4. It speeds things up a lot. I was using (and still do) an RCBS Chargemaster then checking the charge with a TRX-925. I still use it for loading for rifles like the 45-70 and some pistols.

The hardest part of switching to it was the hundredths value actually being right and letting .02 gn go by without caring about it for most charges

Back on topic, I gave up on N133 and I'm working with CFE BLK. I have some "unicorn powder" aka H4198, but I'm going to be patient and wait for the barrel I ordered for the Solus before I test with it.

If lt works out I'll shoot the CFE BLK test tomorrow. I like my new barrel. Not a fan of the AR10 (not a hater either) but she sure is running good now.

Consider IMR 4227 which is now my go-to powder for 8.6 BO. I'm getting sub MOA with my 1:3 Fix at 100 yards using 300 gr SMK.

Chipster697 · Oct 24, 2024

45-90 said:
I checked into the 338 ARC even made a die to mock up a case. It’s almost the same as the 338 Spectre, just .030" longer with its shortened 6 mm ARC case.
<snip>

Feeding may be problematic with Grendel mags, and barrel extensions need modified to fit .338" bullets.

<snip>

You are the first person I’ve seen mention the barrel extension, but that was one of my first thoughts. Revealing my ignorance, do 300 Blackout barrels have different barrel extensions from 5.56?

45-90 · Oct 24, 2024

Chipster697 said:
You are the first person I’ve seen mention the barrel extension, but that was one of my first thoughts. Revealing my ignorance, do 300 Blackout barrels have different barrel extensions from 5.56?

Yes for best results feeding, the 300 Blkout should have wider or larger diameter feed ramps.
The big boys like the 450 bushmaster have one large cutout in the center for single stack center feed mags to get those big wide bullets to feed into the barrel.
You can do this with a hand grinder if your careful. But if doing a barrel for the larger calibers from scratch it's best to screw the right barrel extension on to begin with, then lightly polish the feed ramps.

MSBRPT · Oct 24, 2024

Shot a ladder test loaded with CFE BLK, 185 grain CX with BR2s in Gorilla brass using a 6.5 twist barrel. Started at 25 grains and bumped up in .5 increments with 2 shots at each step. Shots were recorded with a labradar, here’s what I got:
Temperature: 51 degrees
25gr: 1st- bad read, 2nd- 1801
25.5: 1st- 1669, 2nd- 1791
26: 1st- 1670, 2nd- 1852
26.5: 1st- 1857, 2nd- 1756
27: 1st- 1696, 2nd- 1754
27.5: 1st- 1723, 2nd- 1838
28: 1st- 1814, 2nd- 1760
28.5: 1st- 1776, 2nd- 1837
29: 1st- 1810, 2nd- 1806
29.5: 1st- 1851, 2nd- 1830
30: 1st- 1908, 2nd- 1877
30.5: 1st- 1908, 2nd- 1908

Stopped at 30.5gr because of a harder bolt lift and flat primer. I was hoping to get at least 2000 fps based off of information in this thread and GRT. Probably should’ve taken the hint that CFE BLK wasn’t going to give me the results I was looking for. Wondering if the 1:3 would’ve looked any different.

DRWilson · Oct 25, 2024

MSBRPT said:
Shot a ladder test loaded with CFE BLK, 185 grain CX with BR2s in Gorilla brass using a 6.5 twist barrel. Started at 25 grains and bumped up in .5 increments with 2 shots at each step. Shots were recorded with a labradar, here’s what I got:
Temperature: 51 degrees
25gr: 1st- bad read, 2nd- 1801
25.5: 1st- 1669, 2nd- 1791
26: 1st- 1670, 2nd- 1852
26.5: 1st- 1857, 2nd- 1756
27: 1st- 1696, 2nd- 1754
27.5: 1st- 1723, 2nd- 1838
28: 1st- 1814, 2nd- 1760
28.5: 1st- 1776, 2nd- 1837
29: 1st- 1810, 2nd- 1806
29.5: 1st- 1851, 2nd- 1830
30: 1st- 1908, 2nd- 1877
30.5: 1st- 1908, 2nd- 1908

Stopped at 30.5gr because of a harder bolt lift and flat primer. I was hoping to get at least 2000 fps based off of information in this thread and GRT. Probably should’ve taken the hint that CFE BLK wasn’t going to give me the results I was looking for. Wondering if the 1:3 would’ve looked any different.

What is your barrel length?

TimberTank · Oct 26, 2024

1ronsights said:
I have also had the same experience as EagleEyeShooting with reforming. I have not had to turn hornady 6.5CM brass necks, though have had brass from other manufactures hang up if I did not turn the necks. I am using hornady dies.

Also like EagleEyeShooting, I also found 35.8gr of AA1680 to be too hot with 225gr barnes TTSXs. I was happier with results when bringing it down to 32.2gr.

I have had so much fun with this cartridge that I think I am going to get the RemAge-style barrel and put together a lightweight bolt action for backcountry black bear hunts as well. Does anyone have any recommendations on a good source for Remington 700 actions?

Thanks,
-JM

Hey JM. Regarding using A1680 with the Barnes 225g TTSX. You said it was hot at 35.8gr. What length barrel were you using? I have a 16” Faxon Remage steel barrel. I know this is 2+ years ago. And it seems to me that was a typo on Faxon/K. Britingham sheet they had put together. If you remember let me know what barrel length. I’m starting at 25.5g.
Sounds like this is too low. Let me know your thoughts if you get a minute. Thanks
T

45-90 · Oct 27, 2024

TimberTank said:
Hey JM. Regarding using A1680 with the Barnes 225g TTSX. You said it was hot at 35.8gr. What length barrel were you using? I have a 16” Faxon Remage steel barrel. I know this is 2+ years ago. And it seems to me that was a typo on Faxon/K. Britingham sheet they had put together. If you remember let me know what barrel length. I’m starting at 25.5g.
Sounds like this is too low. Let me know your thoughts if you get a minute. Thanks
T

Do Not even try the A1680 35.8 gr load with the 225 gr bullet ...it will blow the primers right out of your brass cases!
Many of us early 8.6 users cautioned Faxon about it, but it took months to take that load off the list, but it's still posted around the net.

st1650 · Oct 29, 2024

Has anyone played with a custom mold for casting 350gr-ish bullets for cheaper subs ?

This one looks interesting

https://noebulletmolds.com/site/shop/bullet-moulds/338/htc339-315-fn-bz1/htc339-315-fn-bz1-5-cavity-pb/

wgranvilleb · Oct 29, 2024

st1650 said:
Has anyone played with a custom mold for casting 350gr-ish bullets for cheaper subs ?

This one looks interesting

https://noebulletmolds.com/site/shop/bullet-moulds/338/htc339-315-fn-bz1/htc339-315-fn-bz1-5-cavity-pb/

The 1:3 twist rate is too violent for lead. Stay with solid copper or bonded.

@45-90 has considerable experience with 1:6.5 and a wide array of projectiles.

Mos-tech is making 1:3, 1:5, and 1:6.5 twist barrels. The 1:5 sounds interesting.

DRWilson · Oct 29, 2024

wgranvilleb said:
The 1:3 twist rate is too violent for lead. Stay with solid copper or bonded.

@45-90 has considerable experience with 1:6.5 and a wide array of projectiles.

Mos-tech is making 1:3, 1:5, and 1:6.5 twist barrels. The 1:5 sounds interesting.

I’ll add that Speer has a cheap $.35 272gr bullet that is a fun plinking sub but only for 5 and 6.5 twist.

st1650 · Oct 29, 2024

wgranvilleb said:
The 1:3 twist rate is too violent for lead. Stay with solid copper or bonded.

@45-90 has considerable experience with 1:6.5 and a wide array of projectiles.

Mos-tech is making 1:3, 1:5, and 1:6.5 twist barrels. The 1:5 sounds interesting.

I’m doing 12.5in 1/6.5 twist on a ARC CDG action with a cone breech so I can use AW mags.
Primary loads will be the 350 REX but kinda looking for a cheap-ish ballistic equivalent for 300-400 long range subsonic steel shooting.
Won’t be super high volume shooting unless I can find a powder as good as N32c for consistent long range subs.
Will be using LRP with Alpha brass. Most likely Fed 210m

45-90 · Oct 31, 2024

st1650 said:
I’m doing 12.5in 1/6.5 twist on a ARC CDG action with a cone breech so I can use AW mags.
Primary loads will be the 350 REX but kinda looking for a cheap-ish ballistic equivalent for 300-400 long range subsonic steel shooting.
Won’t be super high volume shooting unless I can find a powder as good as N32c for consistent long range subs.
Will be using LRP with Alpha brass. Most likely Fed 210m

There are not too many cheap 338 bullets.
The 272 gr was cheap, but I just use them for plinking, along with Speer 338 bullets.
The 250 gr Game king BT may provide similar ballistics but less weight for ringing steel... it was fairly accurate...and a bit cheaper.
For lead casting I'd go with 315 gr NOE, its designed for subs with high tech coatings, I have not used them in the 8.6 but this one is designed for the Spectre 6.5 twist.
I personally use 300 gr SMK or 300 Berger for any long range shooting, each has a different powder preference in my 6.5 Twist barrel. Try to find free shipping days, and discounts to help lower your shooting costs.
.

st1650 · Oct 31, 2024

45-90 said:
There are not too many cheap 338 bullets.
The 272 gr was cheap, but I just use them for plinking, along with Speer 338 bullets.
The 250 gr Game king BT may provide similar ballistics but less weight for ringing steel... it was fairly accurate...and a bit cheaper.
For lead casting I'd go with 315 gr NOE, its designed for subs with high tech coatings, I have not used them in the 8.6 but this one is designed for the Spectre 6.5 twist.
I personally use 300 gr SMK or 300 Berger for any long range shooting, each has a different powder preference in my 6.5 Twist barrel. Try to find free shipping days, and discounts to help lower your shooting costs.
.

I've located some cheap-ish 300 Lapua Scenar locally, so that'll do for now ... I always want to maximize the case capacity so the longer, the better.
250Gr would probably work really well with Trailboss but I'm getting low on stock and I'm not sure if they've re-started producing it yet.
Seems like Hornady won't release the 307 SubX as a bullet component this year.

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