IN STOCK 6mmARC Mk136 Mod2 Bolts

[Shoreglide]

I'll stay on the list as well.

[BluntForceTrauma]

U P D A T E : Problem solved. Turned out simple.

Was working on the extractor drawings in detail, calculating the claw dimensions, when it occurred to me: "Maybe the claw, the 'fang,' is simply too long. What if I just file down the 'fang' a touch and make it shorter? Then the extractor hump won't be pushed up as high and grind and bind against the extension teeth."

Took out the ol' Makita angle grinder with a metal grinding wheel, gripped an extractor in some pliers, and kinda touched the bottom of the extractor claw to it. Some tiny sparks flew. Soon the bottom of the extractor claw was a shiny silver — a little chewed up like a tiny chihuahua got after it — but it was, indeed, shorter.

Reassembled the bolt, installed it in a gun with my dummy firing pin, and hand-cycled a magazine: Slick, smooth action and a beautiful pile of cartridges. Hallelujah!

Now, how to "fix" 100 extractors on an industrial scale with perfect mechanical precision? Ain't gonna Billy-Bob angle grind 100 extractors. So that's the next problem....

[pavementends]

Good Job!

[Bigdaddyjak]

2 for me !

[BluntForceTrauma]

U P D A T E : Extractor Mod1 re-design is going well. Gonna be kick-ass!

[pavementends]

Any timeline?

[BluntForceTrauma]

No timeline yet.

[BluntForceTrauma]

U P D A T E : Prototype MONSTER Mk136 Mod1 extractor is in and it frickin' cycles like butter. (See photo.) Very happy. Going into production.

You guys remember how all these extractors for the alternate AR calibers are weaker than a standard 5.56 extractor?

My Mk136 Mod1 extractor has 100% of the claw thickness of a standard 5.56 extractor and 97% of the head thickness. Some smart-ass is gonna say, "Wait, only 97%?" Dude. Ain't gonna get any better than that. You wanna go back to 50% like other 6mmARC/6.5 Grendel extractors? Didn't think so.

So, our 6A/65G extractors are now basically as strong as any 5.56 extractor.

That. Is. A. Good. Thing.

Keep you updated on production ETA cuz, unfortunately, it ain't lookin' pretty these days....

[Old Bob]

Cool!   I'll still be waiting for them to become available.

[skyrep]

That's great news.  Can't wait for them to be available.

[KenC]

TriangleVelvet, my MONSTER bolts use the same manufacturer and heat-treat process as Bill Alexander developed and used back when he was still at Alexander Arms.

They are sort of the industry standard for Grendel bolts — I just sell 'em for $55 when most others are selling them for $75. This guy that is worried about his MONSTER bolts and wonders if he should get a Toolcraft bolt, instead.... Toolcraft doesn't make their own bolts. Their bolt vendor (great guy, chatted with him at SHOT Show) uses boltface walls that are even thinner than my bolts. Go figure.

But, yes, we are aware of the embrittlement problem with nitriding small parts. Our heat treat process is the dark art part of this equation, and eliminates QPQ nitriding as a source of concern on my MONSTER bolts while retaining the benefits of corrosion resistance, strength, and lubricity — all at an attractive price that also does not change the part dimensionally.

You will notice we only provide parkerized extraction claws, because we agree that nitriding would make the small areas of that part too brittle for its task. But the bolt bodies themselves do just fine nitrided, and the history of the industry with these bolts — and my personal history as a vendor — proves this beyond a doubt.

Now, we all know any Grendel or 6ARC bolt is gonna be "weaker" than any 5.56 bolts when one compares amount of steel material in the boltface ring that the lugs sit on. Obviously, it was a simple engineering challenge, and the maximum average pressure of 52,000 that the cartridge was designed for took this into account. Where a 5.56 might have a bolt life of 7,500 rounds, a 65G/6ARC bolt might have a life of 5,000 rounds. Nature of the beast. (I'm not saying anyone has actually rigorously and scientifically tested this — maybe the military entity that requested the 6ARC in the first place?) Of course, all that depends on a hell of a lot of variables.

Nobody was trying to trick anybody or pretend the fatter Grendel (and .50 Beowulf) and now 6ARC cases didn't put different stresses on the bolt than the smaller 5.56 case.

So it is what it is. Meanwhile, tens of thousands of 6.5 Grendel, .50 Beowulf, and 6mmARC shooters have understood the engineering compomises necessary to fit a larger cartridge into the AR15 platform and have successfully engaged with the platform.

Now, to the "rumors," and this is where it gets messy.

There is a vendor who specializes in 6.8 SPC barrels and is kind of a cult-like leader with his customers. I respect the guy's technical knowledge, his work ethic, and his ability to think outside the box. But he believes everyone else in the whole world is an idiot or is trying to cheat him, and he's not above starting nasty rumors to denigrate those in the firearms community he perceives as his competition or his enemies.

He's recently and loudly proclaimed he will no longer nitride bolts cause he says they're unreliable. His acolytes take this as gospel and run with it to various other forums. He's also recently proclaimed he will no longer sell nitrided barrels cause they are also unreliable. Wut?!? So, he's apparently got issues with whoever he uses for nitriding of both his barrels and his bolts. But the fact that he's having issues does not mean the rest of us in the industry are.

We have no such problems with the nitriding of our barrels and our bolts. That's not to say things don't go wrong in the world of manufacturing, let me tell you. Around 2015, for example, when I got Faxon into the Grendel game, I got a batch of barrels where the nitriding had been botched and they had to be replaced.

Long story short: 65G/6ARC bolts are weaker than 5.56 bolts for engineering reasons. This is obvious to everybody; nobody is trying to hide this fact. For those of us who are fans, the performance gains outweigh the engineering compromises that had to be made. While people break 5.56 bolts for various reasons, they are also going to break 65G/6ARC bolts for various reasons. Is it "common" in the 65G/6ARC world? No. Only in the eyes of those who have their own reasons for blowing the issue out of proportion for their own advantage.

Bottom line: If you're gonna shoot 65G/6ARC, you're gonna need a bolt. Personally, my MONSTER bolts are as good as any and better than most and at a lower price, to boot. On the Grendel forum, we've seen every brand break over the years, so there's no "magic" bolt.

Having said that, this next batch due soon — knock on wood — has a slightly thicker lug rim. I call them Mk136 Mod1. And, yes, they'll be nitrided. 

Just let me know. Put me on the list for one or two. Thanks.

[41bear]

I know we are all waiting on your news but do you have any idea when your new bolts will show up?

Now that the Delta variant is out and about I'm sure it's hard to say but a ball park figure would be nice, I promise I won't hold you to it.

Thanks

[BluntForceTrauma]

I know we are all waiting on your news but do you have any idea when your new bolts will show up?

Now that the Delta variant is out and about I'm sure it's hard to say but a ball park figure would be nice, I promise I won't hold you to it.

Thanks

No new updates. Still waiting for responses to my emails.

[41bear]

Got it, I'm just going to be patient cause I want 4 of those bad boys.

Gotta remember my mom's saying "A watched bot never boils."

[gorillamotors]

How can I put myself on the list for two bolts and two 20" 6mmARC barrels?

Jim

[skyrep]

I am still good for two bolts.  Buy once, Cry once.  I am sure the wait will be well worth it.
Thanks for the update

[BluntForceTrauma]

U P D A T E : Manufacturing continues to be jacked up. Email from bolt rep yesterday says, "Unfortunately, we do not have enough raw material to meet our open orders and won’t have more until the end of October."

[41bear]

John are we still in limbo about answers from supplier? From all the negative truck driver talk it appears that the supply chain is broke. Being in Savannah the talk here is that the port is having a very real problem with drivers and it won't get better any time soon.

On the bright side I do have one Grendel SB from ARP that I'm going to use to start upper limit testing.

[BluntForceTrauma]

News is still bad. In his latest email reply, my vendor says, "That was the plan, but unfortunately, we ran out of raw material. The mill won’t have anything for us until mid-November."

[41bear]

News is still bad. In his latest email reply, my vendor says, "That was the plan, but unfortunately, we ran out of raw material. The mill won’t have anything for us until mid-November."

Thanks, it appears like the attitude we should adopt is a military one. "Hurry up and wait."