6.5 Grendel II barrel???

[se3388]

I have read a lot of the posts about it but I was wondering is there anything bad about the Grendel II chambering. Now I don't like it or dislike it but it seems like it's design allows you to seat bullets out farther and that would not take up powder space and seems like it would keep pressures lower. I was looking at the Stoner/Midway barrel but read about problems and then have read that the problems were fixed now. Why was the II chambering invented?

Steve.............

[NugginFutz]

Search is your friend...

[KentuckyBuddha]

https://www.google.com/cse/home?cx=016368947416500061353:paqd_0xcu1o&hl=en

This is a dandy link to put in your favorites!

[se3388]

I used the search feature as well as using Google and am still confused, it looks like a good thing but a lot of people don't see it that way. Is this just a case of you love it or hate it thing? Has the problems with Stoner/Midway barrels been fixed, are the barrels any good?

Steve............

[Bwild97]

The "Grendel II" designation will only cause more confusion as individuals take interest and look for rifles and barrels chambered in 6.5 Grendel. A chamber that allows loading COAL beyond 2.300" is not advantageous, since most magazines limit COAL to 2.265 - 2.310. If chamber leade is excessive the rifle will exhibit signs of being "Shot Out". So the only good thing about the "Grendel II" designation is that there should be no more short chambered barrels sold from Midway and Liberty.

[bwaites]

There is nothing inherently bad about the chamber. If it were in a bolt gun, it might allow longer bullets to be loaded, freeing up some case capacity for powder.

However, in the AR15, the longer throat isn't really useable because the overall cartridge length is determined by the magazine. Many of the longer bullets, which would probably see an advantage if they could be seated out longer, like being closer to the lands. Since you can't load them long because of the magazine, you can't get them close to the lands to make them accurate, either.
The chamber of the Grendel is fairly unique in designs used in the AR15, in that it has 2 angles into the caliber sized, engraved barrel. The first angle serves to help center the bullet, while the second eases the centered bullet into the bore. This design was used to allow the use of many different bullet designs and weights with the cartridge. Since all those bullets had different ogives, they all shot differently from standard chambers because of the great variation in length and amount of freebore in comparison to that length.

The chamber was a compromise, allowing bullets all the way from 85 grains to 140 grains to shoot well. Some spectacularly well. Some manufacturers have called it a "machine gun chamber" because it seemed so loose compared to conventional wisdom regarding accurate chambers. This tends to directly contradict what some seem to be experiencing with their barrels. However, it does seem to have achieved its design, allow good accuracy with all bullets in the weight group mentioned. Seldom do you hear anyone say, "I can't get this barrel to shoot anything well!"

Les Baer chose to go the other way, making a chamber with a somewhat tighter neck, (though still able to chamber factory ammo without difficulty when properly machined), and with a conventional throat. He wanted ultimate accuracy with either of 2 bullets, the 123 AMAX or the 123 Sierra HPBT. By all accounts, he achieved this with his chamber, so much so that he offers an accuracy guarantee shooting factory ammunition. Many others have used this chamber with good results as well.

The problem with the Grendel II chamber is that it doesn't use either method to effectively center the bullet, a tight neck OR a compound throat.

[nincomp]

edited to add: Dagnabit! Bwaites has again posted excellent info while I was slowly typing away. Rats.

. I was looking at the Stoner/Midway barrel but read about problems and then have read that the problems were fixed now. Why was the II chambering invented?

Steve.............

I will provide a bit of information, since the original threads have been moved twice and are long, tedious, and contentious. My old links do not work anymore, so the search function may be confusedas well.

If you have read about the Stoner/Midway issue, you will realize that a number of members feel cheated and lied to. In short, some people bought new barrels marked "Grendel" and discovered that some factory ammo would not fit. They were assured that the chambers and throats were within spec. Nevertheless, many had to pay to have the throat reamed enough to take factory ammo. I will, of course, not publicly say that I agree with them. No sir, not me. These "Grendel" barrels disappeared from Midway and before long "Grendel II" barrels, with a larger reamed throats, suddenly appeared. This does not generate a warm, fuzzy feeling about Stoner, Saturn (the actual manufacturer), or Midway, for that matter.

Technical stuff:
First of all, Grendel II is a bit of a misnomer. Its leade/throat combination was tried then rejected by the Grendel design team. A true Grendel has an unusual 2-angle "compound throat." This feature was created to allow more bullet shapes, in particular those of some match or competition bullets, to shoot well , given the cartridge length constraints of the AR15 magazine. The "Grendel II" chamber has a more typical straight section (leade) followed by single angle throat. It is in fact more closely related to the .264 LBC chamber than the Grendel one.

"Why was the Grendel II chambering invented?" As noted above, it uses a more typical leade-throat configuration. As it turns out, the reamers are easier to make and easier to resharpen. The second reason, which is the sore point with many in this forum, is that the "Grendel II" leade-throat is shaped so that Grendel throats, undersized or not, will be completely removed by the new reamer. It is generally believed that some of the original "Grendel" chambers were flawed, as were some of the cambers in unsold barrels. Some believe that the unsold barrels were recalled, reamed with the "Grendel II" reamer, relabeled then returned for sale.

When all is said and done, rifles with the "Grendel/LBC II" can be accurate. Loads that perform well in a .264 LBC barrel will likely do well in them. The section of one of the older threads that I suggest you read are pages 7 and 8 of the following:

http://www.65grendel.com/forum/showthread.php?8330-Grendel-II-chamber/page7

If you are a true masochist, read all of the related threads. Don't say that I did not warn you!

[waveslayer]

I had bad Grendel throat from.... they took care of it, but I lost about 70 fps once it was returned to me. It's accuracy didn't suffer just the fact that is not like my other Grendel and the restriction of the OAL because of the msgs, annoys me. There is no benefit to you or anyone with the longer throat. Unless it's a bolt gun, which defeats the whole purpose of the Grendel.

[se3388]

After reading the link from nincomp and bwaites post it is a little more clear, thanks everyone for their input. I have the 'original' Grendel chamber in my Mini Mauser and it shoots fantastic so I am satisfied with it. Thanks again Guys.

Steve...........

[se3388]

I think I have it figured out after reading both sides of the arguement. The 6.5 Grendel II is a fine cartridge, it is a variant of the 6.5 Grendel another fine cartridge. The original 6.5 Grendel was designed a certain way and that is what was approved. I like the 6.5 Grendel, I like the 6.5 Grendel II also, I have both. Nothing to get mad about it's just a different design, ever how slight. I'm sure I'll enjoy both of mine for years to come. I apologize in advance if I offend anyone.

Steve............

[rickOshay]

I think I have it figured out after reading both sides of the arguement. The 6.5 Grendel II is a fine cartridge, it is a variant of the 6.5 Grendel another fine cartridge. The original 6.5 Grendel was designed a certain way and that is what was approved. I like the 6.5 Grendel, I like the 6.5 Grendel II also, I have both. Nothing to get mad about it's just a different design, ever how slight. I'm sure I'll enjoy both of mine for years to come. I apologize in advance if I offend anyone.

Steve............

At least we finally all agree that the Grendel II is a variant and not a SAAMI 6.5 Grendel.

I would say that your statement of the GII being a fine chamber has yet to be demonstrated. This claim about longer seating of certain bullets was being made before the chamber was even available. While many of us have doubts about the performance of the GII, I understand a group buy was done, and people are getting them. So lets see the range reports before we pass any judgements - good or bad.

Many have doubts that the GII will demonstrate the claimed advantages over the SAAMI Grendel for long bullets. Here are some posts about what the Grendel chamber can do.

The SAAMI Grendel can handle long bullets with the right powder:

http://www.65grendel.com/forum/showthread.php?8543-N530-and-long-bullets

The SAAMI 6.5 Grendel is accurate over a wide range of bullets:

http://www.65grendel.com/forum/showthread.php?8555-Accuracy-of-a-wide-range-of-bullets

And what can we expect from gaining longer seating depth? (Post #23):

http://www.65grendel.com/forum/showthread.php?8330-Grendel-II-chamber&p=91209#post91209

And finally, the rifle used in those posts was made by Satern. So now Satern claims that the chamber in that barrel is faulty, and introduces a new chamber. To me, that sounds like pure marketing - given the original chamber does pretty well.

But lets wait for the range reports. NINCOMP started a thread for posting range data for this chamber.

http://www.65grendel.com/forum/showthread.php?8476-Grendel-II-Accuracy-and-preferred-loads

No data yet.

[waveslayer]

But lets wait for the range reports. NINCOMP started a thread for posting range data for this chamber.

http://www.65grendel.com/forum/showthread.php?8476-Grendel-II-Accuracy-and-preferred-loads

No data yet.[/QUOTE]

There has been data posted. I posted my results the week after I had my throat scraped. I had pressure sings at 31.4 grains of CFE with the 123 SST bullet. After scraping I was able to go up to 31.9 before in had any pressure signs. Same seating depth. The velocity had very little change. I settled on 31.2 grains of CFE and shrunk my groups from .516 to .388. So the results are in.

I'm not a fan of the new chamber but stating that the results will speak for themselves has already been proven awhile ago.

Would I ordered a Grendel II? No, I will stick the the normal Grendel. Am I upset, I was until they fixed it and now I'm a happy camper.

[JASmith]

There has been data posted. I posted my results the week after I had my throat scraped. I had pressure sings at 31.4 grains of CFE with the 123 SST bullet. After scraping I was able to go up to 31.9 before in had any pressure signs. Same seating depth. The velocity had very little change. I settled on 31.2 grains of CFE and shrunk my groups from .516 to .388. So the results are in.

I'm not a fan of the new chamber but stating that the results will speak for themselves has already been proven awhile ago.

Would I ordered a Grendel II? No, I will stick the the normal Grendel. Am I upset, I was until they fixed it and now I'm a happy camper.[/QUOTE]

Is there a possibility you could copy your comments into Nincomp's thread? Others will likely follow, and we should then get a better feel about how well this variant works.

Thanks!

[JASmith]

But lets wait for the range reports. NINCOMP started a thread for posting range data for this chamber.

http://www.65grendel.com/forum/showthread.php?8476-Grendel-II-Accuracy-and-preferred-loads

No data yet.

There has been data posted. I posted my results the week after I had my throat scraped. I had pressure sings at 31.4 grains of CFE with the 123 SST bullet. After scraping I was able to go up to 31.9 before in had any pressure signs. Same seating depth. The velocity had very little change. I settled on 31.2 grains of CFE and shrunk my groups from .516 to .388. So the results are in.

I'm not a fan of the new chamber but stating that the results will speak for themselves has already been proven awhile ago.

Would I ordered a Grendel II? No, I will stick the the normal Grendel. Am I upset, I was until they fixed it and now I'm a happy camper.

Can you copy this note to Nincomp's thread. That should get the pumped primed and we might get a better idea of how well this variant works.

Thanks!

[se3388]

It seems that the Stoner/Midway Grendel II barrels (or at least some) are marked
6.5 Grendel 1-8 5R.
Still something to further muddy the water.

Steve............