Bolt Group Buy - Possible?

[cory]

Thats what he said.

Awesome does he have in his possession a unused Grendel Bolt to compare his finished product too.

How quick could he get one produced and get it to someone intimate enough with the Grendel Bolt to do a quality check for us.

I wonder if Bill A. or Mark at PF would be interested in taking a look at it for us.I know if I was them I'd be seriously interested in the possibility of Maxim Firearms as a future bolt supplier.

[XcountryRider]

Frank needs a bolt for an example. Anyone have a bolt they can lend to Frank? If you do give him a call.

[Tedward]

Frank needs a bolt for an example. Anyone have a bolt they can lend to Frank? If you do give him a call.

I called Frank and will send him one.

I think the LBC is the best bet because if you need a replacement, either Maxim will have them or LBC. I don't want to count on AA for answering phone calls or taking a month to enter your order then wait for an unknown amount of time.

I have a spare LBC and I can pull my AA. Which ever I'll talk to Frank but waiting on his return call.

[lilharcher]

I'd provide him with the AA bolt, as Bill has done the most R&D to produce what most consider the finest bolt for this particular caliber.

[explorecaves]

I would prefer an AA bolt to use as an example....

[XcountryRider]

I would prefer AA bolt be provided.

[Tedward]

Well then I'll send him the Hard Use AA Bolt.

Maybe we'll get the special notch in the lug

[cory]

I'd provide him with the AA bolt, as Bill has done the most R&D to produce what most consider the finest bolt for this particular caliber.

+1 It does need to be an unused bolt.

[Tedward]

+1 It does need to be an unused bolt.

Then you will need to send yours.

[cory]

Then you will need to send yours.

I would if I had one.

[Tedward]

I would if I had one.

I can send mine as I said but mine has about 30 rounds of use. So that being said, it should not matter. It does not have any signs of ware and has the factory finish. My LBC showed more ware after 30 rounds so the AA finish is a better too.

I told this to Frank and he said that it won't be an issue. I think that were fine....

I'll send it later today from the East Coast so he will have it this weekend to get the measurements he needs.

[lilharcher]

Thanks Tedward.

[stevegun 1]

Other than material, .136" bolt face depth and the extractor tolerances, what other differences will Frank need to consider from the bolts he makes?

[XcountryRider]

Awesome your the man!!

[Sputnik]

Did Frank say how he decided to do this? When we spoke he was looking at a small trial run of a few hundred, then another run of a few thousand. It seemed like it was a first come first served. Or are we going to compile names for this group buy? I suspect there are a few still waiting for bolt information before they decide on the barrel buy too. I also saw some interest in BCGs. What is the latest there...prices?

[XcountryRider]

Once he's up and rolling he'll take orders directly.

[Buster]

Once he's up and rolling he'll take orders directly.

Nice! Did he give any time frame that he could be up and rolling?

[Tedward]

No he has not said anything today on ETA but called me and I missed his call. It's 11:22am his time and I'm leaving work now, 2:22pm in VA. I'll let him get back in touch with me but I'm going to let him do his job. Me calling and asking questions will only take his time away from doing what already knows he needs to do.

He'll make a run and most likely get some testing done but this is not his first picnic and he has a plan...
As for all the options, once the run gets moving he can give an ETA and all the options.

Last night he said the material is no issue so him getting the bolt, taking measurements and updating programes is more important than anything so please bare with him, when he calls me, I'll pass the word. If he contacts someone else they might have something to pass along but it is best if nobody calls asking more questions....
let the doctor do his thing.

Have a good day guy's, were on the right path....

[LRRPF52]

I talkeed to Frank today too and had been talking to him months ago about bolt carriers. As you said he has big deliveries and our needs he wants to help out. He is willing to make the run and put some on the shelf and help out any of these other manufactures who need the 6.5 Type II bolts. It's just an upfront expense and he doesn't want any money from us, just wants to make sure others don't do the same think he is going to do. So that being said, he will let us know Monday as to what the company will do.

He did log onto the forum and read everyone's comments and concerns. I asked him to sign up so if your reading this just join in on the fun Frank....

One thing was told to me is the material used on the enhanced bolts is 9310 which is harder/stronger than the Carpenter 158 used on other carrier parts and less powerful cartridges. Due to the Grendel pressures of 50,000psi and people hand-loading a hot load, the bolt needs to be rated a little higher, 62,000psi or so. That is why the Carpenter 158 had issues and the "Enhanced Bolt" was made. I am pretty sure the main difference was the material, 9310.

If someone know's exactly the specs. for the material used on the Grendel Bolts, please confirm what I said is correct. Frank is willing to use what ever material we need.

LOG ON FRANK.....

Nobody should be loading for the Grendel in the AR15 past the maximum published loads. 62,000psi is about 10,000 psi more than max loads. The bolt thrust and bolt geometry of the AR15 bolt barely support 62,000psi pressures that long in 5.56 NATO.

The original AR15 bolt geometry was built around a 50,000psi SAAMI max cartridge, the .222 Remington. When that evolved into the 5.56x45 (and civvy version .223 Rem), the pressures were raised significantly, without what I feel should have generated an engineering and blueprint change for the whole system. Since it would have only changed dimensions by maybe 2/10's of an inch, it wasn't pursued. (new bolt, new extension, new magazine, new upper)

Carpenter 158 was specifically selected for the military bolts because it could handle the higher pressures better than 8620, but they also added the High Pressure Test load, followed by Magnetic Particle Inspection (HPT/MPI) to see if microscopic stress fractures had been induced by the HPT load.

Carpenter 158 is very difficult for a shop to get, as you have to order high volumes of it. It is an excellent steel for AR15 bolts. Harder does not mean stronger, especially when you look at shock force on a steel part. You want a balance of substrate ductility, with great surface hardness, and a steel that takes heat-treating well without the surface becoming too brittle. If it is so hard that it fractures on the surface, you will start cracking bolt lugs or the cam pin hole walls.

Frank is very aware of these things, and has been dealing with AR15 BCG's as an OEM supplier for a long time. In the end, engineers will most likely be involved with selecting the optimum bolt material, dimensions, and heat treating, as well as extractor steel.

[cory]

Nobody should be loading for the Grendel in the AR15 past the maximum published loads. 62,000psi is about 10,000 psi more than max loads. The bolt thrust and bolt geometry of the AR15 bolt barely support 62,000psi pressures that long in 5.56 NATO.

While this is true, the bolt still needs to be designed with a Factor of Safety (FoS).
Factor of Safety=Ultimate Load/Allowable Load

I've read here before were Bill A had said he had to proof test the bolts to 62ksi. This gives us a FoS of 1.19.