6.5 Grendel confusion - Type 1 / Type 2 / 264 LBC...help me please

[Smitty192]

I have decided to venture off into the 6.5 Grendel world. The more I read, the more confused I get.

Type 1 / Type 2 / 264 LBC chambers, - .125, .136 & 762x39 bolts - compound throat & tapered throat...I'm lost.

What the hell is the difference in the 6.5 Grendel & 264 LBC chambers? Does it matter at all? Do they will all shoot factory ammo?

Once I get the above mess sorted out, I'll need some help with finding a barrel please.

Any thoughts, suggestions and comments, snide and otherwise, are greatly appreciated.

Thanks

 

[FCS]

Craddock Precision, 6.5 Grendel barrel with bolt that is headspaced for chamber.
You can get barrel dimensions you want (18", rifle gas, contoured as desired) and all the compatibility issues go away.
Will shoot factory ammo pretty darn good and custom / handloaded ammo even better.

 

[Strykervet]

Most common: If it's a 6.5G barrel and it does NOT say "SAAMI" on it, use the .136 Type 2 for compound chambers (which is actually the older one). This chamber is the desirable one but some folks claim bolts break easy. I've never had that problem in a Satern or Lilja barrel w/AA bolts. The Satern is the most accurate AR I have, 20" and prints .33MOA consistent with the proper handloads (Bill A. turned me onto these 120gr. Nosler BT's, all I use now).

IF it says "SAAMI" on the barrel, use the .125 Type 1. You only use this bolt with the SAAMI Type 1 straight chamber.

If you use whatever LBC makes, then use their stuff.

Do NOT buy a cheap Grendel barrel that uses AK bolts.

If Satern has a barrel you want IN STOCK then get it. Otherwise, don't bother, you can't effectively order anything custom from them. Krieger has a pretty quick turn around for semi-custom barrels though. And a vet discount if that's you. Lilja probably makes the best button rifle but it costs almost as much as the cut rifles do, still I'll mention 'em. There are others for sure but these guys are the usual culprits making the high end barrels.

For the best bolt and/or carrier group, get the JP FMOS, hands down. I firmly believe the JP FMOS to be the best BCG for the AR regardless of caliber. AA bolts ain't bad either and use a reinforced extractor. Satern comes with an AA bolt I think and I wanna say Krieger headspaces with a JP bolt and includes it for extra (it's worth it unless you plan to get the entire group from JP).

Or you can PM me and I can sell you one of my extra AA bolts if you need one and have a carrier already. I have extra and can probably let one go for a fair price or trade for other AR parts.

 

[Constructor]

I have decided to venture off into the 6.5 Grendel world. The more I read, the more confused I get.

Type 1 / Type 2 / 264 LBC chambers, - .125, .136 & 762x39 bolts - compound throat & tapered throat...I'm lost.

What the hell is the difference in the 6.5 Grendel & 264 LBC chambers? Does it matter at all? Do they will all shoot factory ammo?

Once I get the above mess sorted out, I'll need some help with finding a barrel please.

Any thoughts, suggestions and comments, snide and otherwise, are greatly appreciated.

Thanks

They both shoot factory ammo but some Hornady ammo has a bulge from being a compressed load, if the chamber is tight it can stick in the chamber.
Usually the 264LBC chamber uses the bolts with a .124 recess. Maxim makes very good bolts both in .124 and .136 recess.

Usually the Grendel chamber uses .136 recess bolts.

The 264LBC and Grendel II have a straight freebore, they can be very accurate depending on who makes the barrel.

The SAAMI Grendel has a compound angle throat, it's not really a freebore and does not align the bullet in the traditional way. It relies on a .5* angle in the throat to push the bullet to the center of the bore after it starts moving.

 

[Greg Langelius *]

I've been experimenting with the 6.5 Grendel over the past year or so. My barrels are both AR Stoner, and are both "2"s, and I'm glad I have them. But, I still managed to break off an extractor hook about a week ago. I was up about 2.0gr of powder beyond published max, and I got what was coming to me. I am satisfied that the Gen 2 bolt has all the reliability one would need, as long as one stays within published charge limits.

Pressure signs don't tell the whole story, as I found out. Trusting 'safe' pressure signs is what led me to believe that I could hotload. The cases held, the extractor didn't. There is a lot of anecdotal info about some pretty spunky loads out there, I believed it and paid a price.

About $50, and that does not consider potential injury. That's what the JP Enterprises 6.5 Grendel Improved Extractor sells for.

I also suspect that the added dwell time inherent in a 24" barrel may have played a part in the extractor failure. I've seen recommendations about +2" gas systems, and suspect that might have helped me with my extra long barrel.

I'm switching to my 20" barrel for further load testing with 120gr bullets, and keeping loads within published charge specs.

The Grendel is probably a different critter when handloaded for bolt guns, but the AR extractor was the weak link that helped me stumble.

I seem to be making all of the beginner mistakes.

Greg

 

[Smitty192]

Most common: If it's a 6.5G barrel and it does NOT say "SAAMI" on it, use the .136 Type 2 for compound chambers (which is actually the older one). This chamber is the desirable one but some folks claim bolts break easy. I've never had that problem in a Satern or Lilja barrel w/AA bolts. The Satern is the most accurate AR I have, 20" and prints .33MOA consistent with the proper handloads (Bill A. turned me onto these 120gr. Nosler BT's, all I use now).

IF it says "SAAMI" on the barrel, use the .125 Type 1. You only use this bolt with the SAAMI Type 1 straight chamber.

If you use whatever LBC makes, then use their stuff.

Do NOT buy a cheap Grendel barrel that uses AK bolts.

If Satern has a barrel you want IN STOCK then get it. Otherwise, don't bother, you can't effectively order anything custom from them. Krieger has a pretty quick turn around for semi-custom barrels though. And a vet discount if that's you. Lilja probably makes the best button rifle but it costs almost as much as the cut rifles do, still I'll mention 'em. There are others for sure but these guys are the usual culprits making the high end barrels.

For the best bolt and/or carrier group, get the JP FMOS, hands down. I firmly believe the JP FMOS to be the best BCG for the AR regardless of caliber. AA bolts ain't bad either and use a reinforced extractor. Satern comes with an AA bolt I think and I wanna say Krieger headspaces with a JP bolt and includes it for extra (it's worth it unless you plan to get the entire group from JP).

Or you can PM me and I can sell you one of my extra AA bolts if you need one and have a carrier already. I have extra and can probably let one go for a fair price or trade for other AR parts.

Thanks for the information and offer on the bolt. This is very helpful.

 

[Smitty192]

They both shoot factory ammo but some Hornady ammo has a bulge from being a compressed load, if the chamber is tight it can stick in the chamber.
Usually the 264LBC chamber uses the bolts with a .124 recess. Maxim makes very good bolts both in .124 and .136 recess.

Usually the Grendel chamber uses .136 recess bolts.

The 264LBC and Grendel II have a straight freebore, they can be very accurate depending on who makes the barrel.

The SAAMI Grendel has a compound angle throat, it's not really a freebore and does not align the bullet in the traditional way. It relies on a .5* angle in the throat to push the bullet to the center of the bore after it starts moving.

Is there any benefit in using either the SAAMI Grendal or the 264LBC / Grendal II chamber? Thanks for your insight.

 

[Smitty192]

Craddock Precision, 6.5 Grendel barrel with bolt that is headspaced for chamber.
You can get barrel dimensions you want (18", rifle gas, contoured as desired) and all the compatibility issues go away.
Will shoot factory ammo pretty darn good and custom / handloaded ammo even better.

Thanks - barrel length and gas system is another question all together. I am toying with the idea of a MK12 6.5 Grendal.

 

[Constructor]

Is there any benefit in using either the SAAMI Grendal or the 264LBC / Grendal II chamber? Thanks for your insight.

Not really, either can be accurate. Cheap barrels =disappointment 90% of the time.