8.6 Blk reloading info

[SaltyDog89]

For subsonic, I wouldn’t focus on weighing brass or getting too deep in the weeds of details. I weighed everything, to include primers, to make sure everything was exactly within a .01 grain tolerance. The combination of bullets, powder and seating depth will have a greater effect. For me, Lapua Scenars had better accuracy and consistency than SMKs. My best sub loads used Lil Gun or N110. I was able to get groups around .5 MOA at 100 meters with a 1:3 Q barrel.

I'll be trying out some 300 grain Bergers when they come in (which should be as good as it gets) but I'll also see how Lil Gun and H110 do also since I have good supply of that on hand already. I would say that a consistent .5 MOA goal would be better than I would think possible for subs but you just set the new mark to reach for I'll go for. Thanks!

 

[SaltyDog89]

First the 3 twist is not for accuracy.... no one is shooting a 3 twist for accuracy.
I was a hunting design with subs up close where 2 to 3 MOA is plenty accurate, at 75 yds and under with the hunting bullets it was designed for.
The 8.6 Blk has too much case capacity with subs for super accuracy.
With all that capacity pressure is too low to burn most powders 100 % leaving larger than necessary velocity spreads.
Then for a high velocity it's basically not as good as the 338 Federal...although I get pretty close with a long barrel.
For short range accuracy 300 yds and under flat base bullets usually have an accuracy edge.

Bolt action and scrap the 3 twist, install a premium barrel with appropriate twist, would be the beginning of an accurate cartridge.
Match bullets get smaller groups...going for accuracy, ya have to be all in for accuracy...hunting is not so much.
Longer barrels for good powder burn, nothing on the end of the barrel, no muzzle breaks or suppressors.
Accuracy looks like a benchrest rifle, and cartridge to match, and 1/4" or less 5 shot groups will happen...like my 6 Dasher.
But you don't want that.
So you get an accuracy compromise.
Hunting doesn't require super accuracy.
The 8.6 Blk is not set up for accuracy.
For subs the smaller cases are better for accuracy like the 338 Spectre 6.5 twist or the new 338 ARC 8 twist should be good.
Because they are capable of complete powder burn in 16" with more powders, and case fill is high where it should be.
But they are not much for supers, because of the small case capacity....compromise again.

My accuracy really improved in 8.6 going from early AR 10 Faxon 3 twist to a Rem 700 with a McGowen 6.5 twist Rem Varmint contour 24" mounted in an aluminum chassis, that I chambered myself.
It has a muzzle brake, but no suppressor.
Now you will have a reasonably accurate rifle.
It's not set up for hunting, but LR shooting 300 gr Match Berger or Sierra at 2000 fps, or subsonic ...with accuracy...with hybrid cases.
Here the bulk of a 10 shot group inside 1" at 100 yds subsonic 300 gr Berger.
A ladder test shooting subs both 285 ELDM and 300 gr Match, shot at the same time... starting in tbe tape and going up as the velocity increases, trying to get the best velocity for both...they hang together here, until they get out of subsonic mode.
Or 200 gr Speer at 2600 fps, pulled one but 7 or 8 shots under 1".
Or 225 gr Speer lead 2407 fps.
Cheap lead bullets under one inch and better.
That's a 6.5 twist barrel versatility, shoots everything well even the 350 Maker Rex.
With a quality barrel, set up more like a target rifle.
But that's not what you want so then compromises are added and accuracy deteriorates.
And a good shot with good eyesight could do better...going blind in my right eye so I have to shoot left handed these days.

Actually, a Speer question here for you.. A 200 or 225gr at 2600, 2407 here respectfully would seem to push above the red line of pressure for 8.6. Am I confusing something here for those or is that accurate? What power/grain/COAL are you using to get those levels safely? I also assume, when you get away from the 1:3 all the risk issues with fracturing apart go away but I'm stuck with solid copper or chance well bonded bullets for now..

 

[DRWilson]

Actually, a Speer question here for you.. A 200 or 225gr at 2600, 2407 here respectfully would seem to push above the red line of pressure for 8.6. Am I confusing something here for those or is that accurate? What power/grain/COAL are you using to get those levels safely? I also assume, when you get away from the 1:3 all the risk issues with fracturing apart go away but I'm stuck with solid copper or chance well bonded bullets for no

The barrel length might be different and the reason for the speed vairance? So with the powder, I would go back through this thread and I think starting at page 16 or so, you will start seeing the data you will need to answer your question. I would also assume that since page 16, most of the data is for 5-6.5 twist rate only. Out of a 16" barrel with suppressor, I can get the 225 ttsx over 2100fps with H335 in a 5 twist barrel. That is a .8 MOA groups of 10. My COAL is 2.75 and my powder is 37gr of H335. NOT for 3 twist.

I think my load is above pressure but I worked up to it and stopped and came back when I got heavy bolt lift. I still don't have any primer signs of high pressure. Even though QL is telling me I am high on the pressure, I verified with real world testing. I know you did the same, I am just sharing my thoughts in case it may help.

 

[45-90]

Actually, a Speer question here for you.. A 200 or 225gr at 2600, 2407 here respectfully would seem to push above the red line of pressure for 8.6. Am I confusing something here for those or is that accurate? What power/grain/COAL are you using to get those levels safely? I also assume, when you get away from the 1:3 all the risk issues with fracturing apart go away but I'm stuck with solid copper or chance well bonded bullets for now..

If you have a 3 twist 8.6 it's a hunting tool, mostly limited to subs, or with all copper for supers...that is a fact.
Why Hornady went with the 8 twist for 338 ARC and over a hundred yrs ago the 44-40 and 38-40 with 1-36 twist at around 1300 to 1100 fps almost decimated the deer herds of N America, killing millions of game animals and small game...close range and put the bullet in the right place, has always worked regardless of twist.

I already owned a 3 twist and know all its limitations....but I'm not gonna hunt with the 8.6, many will.
If that's what you want, keep it...1.5 to 2.5 moa will kill a truck load of deer or pigs just as it was designed at 100 yds and closer, but that can be stretched a bit if one practices alot.
For cheap Speer jackeded bullets shooting unlimited velocities in 8.6 case plus accuracy the 6.5 twist with a premium barrel is the way to go (imo) ya give up nothing but the problems and limitations of the 3 twist...Remember Hornady is running an 8 twist with the 338 ARC, a much smaller cartridge than the 8.6.
My super loads have been published many times in these pages.

I use 62,500 to 65,000 as the Max pressure, because that's what I run my brass 338 RCM, & 308 ARs etc and 8.6 Blk...not for 3 twist. Then ya have to work up, and Alpha brass was recommended for bolt gun 8.6 use as reported early on for those not wanting to deal with making hybrid cases.

My 3 twist can not take the same powder charges as the 6.5 twist, I did that experiment before scrapping the 3 twist.

I also use hybrid cases that will handle 80,000 psi in a the 6.5 twist bolt gun...but do not publish those velocities, plus they have a bit more case capacity.

You can hand load using any process that works for you.

I do not weigh cases, primers, bullets...or break in barrels.
Many of the powder charges will be thrown, and loaded in a Dillon progressive, for many of these loads, and will shoot well under 1", but will be weighed if close to max, with super high pressure loads.

Pic two AR rifles, same caliber, shot on the same day with the same match ammo...one a standard AR barrel guarantees 1"- 3 shot groups...well 3 of the 5 in the 2.5" group are close to 1" ...so it kinda qualifies.
But the lower .5" 5 shot was the first 5 shots out of the new premium barrel, costing more than twice as much.

The next pic are the 80,000 psi hybrid 8.6 cases you have to make to get them but they are available. These are run at 65,000 psi so the data could apply to any 6.5 twist bolt gun in 8.6, if worked up to, or stop when your chamber doesn't handle the pressure in Alpha brass.

 

[45-90]

Just to add to the already great replies, I was discussing 1680 and CFE BLK with Paul Maker for use with his subsonic loads, as I am about to get into subsonic load develpment as well, and he told me the following:

"CFE Black and 1680 works well for supersonic 8.6 blk but is not very accurate with subs. N110, H110, W296 and 11FS has been the most accurate powders. 14.5 gr of N110 is what once of my OEM's uses."

This was for the 350 Rex Subsonic expanding but based on what I've read and what Paul said, it's better to stick with the faster burning powders.

For super's I'm a firm believer in H335, you can search this thread for lots of good load data.

Maker says for the 350 gr Rex expanding for 3 twist barrels ... on their site... DO NOT USE CFE-BLK or AA1680 ... 1050 fps Max muzzle velocity.
Use H110 or W296...around 14.5gr in 16" autoloader.

I shot this in my 6.5 twist bolt gun at 16.1 H110 gave me 1129 fps with the 350 Maker...not limited to 1050 fps I ran it to 1670 fps with excellent accuracy...with RL17.

 

[wisconsinboy]

Maker says for the 350 gr Rex expanding for 3 twist barrels ... on their site... DO NOT USE CFE-BLK or AA1680 ... 1050 fps Max muzzle velocity.
Use H110 or W296...around 14.5gr in 16" autoloader.

I shot this in my 6.5 twist bolt gun at 16.1 H110 gave me 1129 fps with the 350 Maker...not limited to 1050 fps I ran it to 1670 fps with excellent accuracy...with RL17.

I copied my conversation with Paul in the message above. As he noted powder selection is due to accuracy issues, not velocity. I run CFE-BLK just fine out of my 16” 1:3 bolt with 350 makers.

I’m confident that 1:3 is fine out of a correctly tolerance, lapped, and machined barrel with the results I have had. I’d bet if you got a quality 1:3 on another action you’d have reasonable results.

 

[45-90]

I copied my conversation with Paul in the message above. As he noted powder selection is due to accuracy issues, not velocity. I run CFE-BLK just fine out of my 16” 1:3 bolt with 350 makers.

I’m confident that 1:3 is fine out of a correctly tolerance, lapped, and machined barrel with the results I have had. I’d bet if you got a quality 1:3 on another action you’d have reasonable results.

I was just quoting from their website, I did not talk with anyone.
Seems their recommendation might be heeded, as helpful, but you can use any powder ya want.
Maker is stating accuracy issues with the 350 gr from users or their experience, seems like you'd want to give their recommendation a try anyway to see if you like it.
I will never own another 3 twist barrel, especially Faxon...
I have no accuracy issues with the 350 Maker and can run it to 1670 fps with accuracy if I like.
But you and others who like the 3 twist or whatever your shooting, keep doing so, it's your gun to pursue your personal endeavors.