8.6 Blackout build. First round, no ejection

[Mike6158]

I have almost finished my 8.6 Blackout build. I need an adapter and some timing shims for the key mount muzzle break and it'll be complete, until the can arrives.

The break attaches but the Faxon barrel has a bit of creativity on the end of it so there's no way to clock the muzzle break. I have "stuff" coming for that.

I put one round, a 210 Grain TSX from Gorilla Ammunition, into the ground to see if the rifle would cycle. I held the AR tight on my shoulder, etc, etc. The round didn't cycle. The bolt closed on the case and pinched the neck of the case. I used a Geissele B2 buffer weight and their braided spring. I'll swap that out with something a little less aggressive.

Got any other ideas?

 

[waspocrew]

I'd check the gas block to make sure it's properly aligned.

 

[Mike6158]

It is. The barrel has one dimple directly opposite the hole. I spent a good bit of time making sure that it was.

 

[Mike6158]

I took the Geissele buffer weight and braided spring out and it ejected fine. I'll test more when it's finished. It should be better when the can is on it.

 

[martinakl]

Post some pictures. I recently put together a bolt action 8.6 BLK with a Faxon barrel. Toying with building an AR as well.


Check these Maker Bullets out:



I ordered 100 of those (220gr) for hunting supersonic and 100 of the 350gr for hunting with subs.
Website (hyperlink below):

Maker bullets: Projectiles

 

[Mike6158]

Post some pictures. I recently put together a bolt action 8.6 BLK with a Faxon barrel. Toying with building an AR as well.


Check these Maker Bullets out:



I ordered 100 of those (220gr) for hunting supersonic and 100 of the 350gr for hunting with subs.

I need to take some photos of it. I'm waiting for USPS to deliver an adapter for the barrel. It's got an odd thread and a taper on it that I assume is designed to match up to Q's suppressor. Q sells an adapter that will give me a flat face to tighten the Key-muzzle brake to. I just need to find M18 thrust washers so I can clock the brake. Here's what the barrel end looks like:

And the Key-mo

And this is the brake with the correct clocking. I ran it to the end then back off to the correct clocking.

As you can see there's nothing to register the brake on. Q makes an adapter that should solve the problem.

I weighed both buffer weights. The Geissele weight is quite a bit longer than the other one and it weighs 126.4g. The shorter buffer weight weighs 107g which is 19.4g lighter than the Geissele. There are 3 weights in the Geissele. 40.7g, 40.5g. and 17.9g. I tried the lighter buffer weight with the Geissele braided spring and it wouldn't eject. So I put what feels like a lighter spring and the smaller buffer weight in it and it ejected. Felt recoil was lower too.

Part of me wants to try the Geissele spring with 81.4g of buffer weight in the longer buffer. That's 25g lighter than the original and another and 10g lighter than the buffer weight that worked. I'm in the if it works don't fix it corner...

 

[martinakl]

Faxon might have what you need as well. My barrel came with an adapter/washer to make a flat face out of that 25 degree taper.

 

[Mike6158]

I saw it but if you look at the photo of the Key-mo when it's clocked properly there are about 2-1/2 threads left. The Faxon adapter is too short. I'm really hoping that the adapter I bought from Q's site isn't the same one.

I may not even need the Key-mo when the can comes in. I need the brake until it does. I may just screw the can on. The can will work on my .338 Edge but that rifle is made to reach out. I don't see myself ever using a can on it. So, I don't really need a quick mount for the 8.6.

I fired my test rounds into damp blackland clay. The left about a 1" cylindrical hole in the clay that was over 6" deep. I didn't find the bullets. It was getting dark and I think I quit looking too soon. This is going to be an interesting gun to shoot.

 

[Mike6158]

Not the best photo but here's where the build stands as of this evening (yes it has a serial number. I edited it out):

It's pretty simple. Aero Precision M5 upper, M5 lower, and M5 handguard. Aero Precision ambi charging handle. Faxon BCG and barrel. Aero Precision M5 parts kit. Geissele Super 42 braided spring and buffer tube (I'm not sure this will stay. I took some weight out but now it rattles. I need to 3D print a spacer or cut one from something. Or just change back to the lighter spring and weight). The trigger is a Geissele SSA-E. Magpul stock and hand grip. Not shown is a Kinetic Development Group m-lok mount for a Harris bipod. Also missing is the Dead Air DA106 key mo muzzle break. Very, very missing is the Dead Air Primal suppressor. Hopefully it'll be approved sooner but typical is probably September.

Optics... What I want is a Thermion Duo DXP50 thermal... It's a bit out of reach. I haven't decided what to put on it. Maybe "just" an FFP scope of some kind.

 

[Mike6158]

I think this will solve my buffer weight dilemma: Odin Works Adjustable Buffer - AR-10
Primary Arms had it in stock. I should have it early next week.

I sent Downrange Products an email asking about an M18 crush washer. They make a 5/8" crush washer. If the tolerances are loose enough it might work.

 

[Mike6158]

Kind of a long post but I remember better if I write it...

I found the brass from the 3rd test shot. It was a little forward of where I was standing. To me that says the buffer weight is still too high at 3 oz. And... that is apparently wrong.

I found the following in an article found HERE:
The easiest way to know what effect your buffer weight has on the rifle is to look at the ejection pattern:

• Think of your muzzle at 12 o'clock and the buttstock as 6 o'clock.
• If the casings are flying out from the 12 to 3 o'clock positions, likely your firearm is over gassed with too light of a buffer.
• From 3 to 4:30 (about a 45-degree angle from the ejection port) you're good to go.
• Any further back to about the 6 o'clock position, i.e. hitting you, your buffer may be too light or the rifle is leaking gas in which case it cannot fully eject the casing with the proper force and you're soon going to experience feeding issues.
• If you have anything but perfect ejection, the simplest and cheapest method of seeking a correction is to check your AR10 buffer weight, then try a heavier buffer.

I converted all of the grams to oz's. The only reason I used grams was that's what the digital scale I have was set to. I don't mind metric... it's just a number. When all of the buffer weight articles are written with oz's it's time to convert

Aero Precision Buffer weight: 3.8 oz
Geissele Buffer weight: 4.3 oz
Removing the lightest weight in the Geissele (makes it rattle): 3.07 oz

I haven't tried the lightened Geissele buffer. I think I'll wait for the Odin Works adjustable buffer to get here or put the Geissele back to where it was. Either way I'll install the adjustable gas block.

These are the two commonly supplied buffer weights. The Geissele buffer that I bought is an H2 and that's typical for a carbine length AR10.

The following info was found HERE:

Heavy or H1:
Consists of one tungsten and two steel weights. Weighs around 3.8 oz.

H2:
Typically composed of two tungsten and one steel weight and weighs about 4.6 oz.

H3:
Normally uses three tungsten weights to weigh around 5.6 oz.

Rifle buffer:
Weighs around 5.0 oz and uses five steel weights and a steel spacer.

Configurable:
You can use different combinations of the included parts to tune your buffer weight to your needs.

If I understand all of this right, the original Geissele buffer, which was the heaviest of the buffers that I have on hand, and an adjustable gas block to let me adjust the amount of gas, should get ejection where it needs to be. This is why I prefer bolt guns

 

[scooch44]

Post some pictures. I recently put together a bolt action 8.6 BLK with a Faxon barrel. Toying with building an AR as well.


Check these Maker Bullets out:



I ordered 100 of those (220gr) for hunting supersonic and 100 of the 350gr for hunting with subs.
Website (hyperlink below):

Maker bullets: Projectiles

Did you have to use a recoil lug with your bolt gun build?

 

[44-40]

I have almost finished my 8.6 Blackout build. I need an adapter and some timing shims for the key mount muzzle break and it'll be complete, until the can arrives.

The break attaches but the Faxon barrel has a bit of creativity on the end of it so there's no way to clock the muzzle break. I have "stuff" coming for that.

I put one round, a 210 Grain TSX from Gorilla Ammunition, into the ground to see if the rifle would cycle. I held the AR tight on my shoulder, etc, etc. The round didn't cycle. The bolt closed on the case and pinched the neck of the case. I used a Geissele B2 buffer weight and their braided spring. I'll swap that out with something a little less aggressive.

Got any other ideas?

If the gas block is aligned correctly, and adjustable gas block in wide open position and it doesn't work...drill out the gas port with the next largest number drill, which you can use to determine the size of the factory gas port diameter.

 

[44-40]

I've had an 8.6 Blackout for after it first came out.
My first response is another sucker is born. I found it to be a rather worthless ***. Barrel was horrible galling, pits, & tears completely across the to the land ...a clean patch revealed rusty and full of fine metal chips, coming off the worst rifling I've ever seen. Had to lap it to find the rifling, which was bad at the chamber but towards the end was in better shape and it might possibly shoot. Faxon did not have this 3 twist nailed down. I told them I'd trade it for an 8 twist, but they finally got back after 2 months and said they a re under license and it must be a 3 twist.
The 3 twist is very limiting, it blew up a 225 gr bullet following Faxon load data inside the muzzle brake and destroyed the brake and the magneto speed bayonet, first shot rather costly.
You can load these take off the muzzle device and it turns into a shotgun ...shoot it inside a cardboard box and hit every side of the box....makes intresting house gun. The Faxon 225 gr load is toooo hot blows primers.
So what's it good for not much if you want to shoot supers....copper only there. And keep lead subs 285, & 300 gr in the 1000 fps or less 900 fps may be better for a suppressor as this caliber will destroy suppressors and muzzle breaks rather easily.
It took a year to warm up to this turd, its functions good now with 300 gr Bergers and 300 SMK fairly accurate and hits pretty good with a 300 gr bullet. The light recoil is kinda of fun to shoot. Other than that I have no purpose for it.
The 450 Bushmaster with Faxon 16 twist will shoot 502 gr bullets super and sub fairly accurate and hits with alot more energ for close sub hunting IMO a much better caliber and more versatile, even more fun to shoot.
I use standard everything on my ARs no heavy buffers, or springs...except 9 mm. I adjust usually open the gasport add an adjustable gas block. and it functions fine.
I find the 3 twist a limiting gimik, too much case capacity for subs only, which is all its good for and not enough capacity for supers.
And I do not recommend buying one...but I had to try it. Now I know.