Grendel II chamber

[VASCAR2]

If it were me I'd pass with this barrel fiasco from the last batch. These barrels may be from that batch and had the chambers reamed.

I have two friends buy 6.5 Grendel Barrels from Brownell's which are $289.99 and currently out of stock but you can back order. I checked both these barrels and bolts. Both were in spec and from the way the first shoot's I'd say the second will also be a shooter. Another option for a cheaper 6.5 Grendel barrel would be J&T Dist. Or maybe Blackhole weaponry which uses polygonal rifling and 264 LBC chamber.

[heinz57grendel]

All of your loads charges and their seating depths will have to be adjusted according to the length of your chamber. I am dealing with this same issue and after talking to mark at precision firearms this weekend at the nra convention, I am going to send my satern barrel off to him to have the throat fixed. My powder charges and seating depths are different from most of all the other info on here. You will be doing your own R&D just as I am doing now. Buy a true grendel chamber.

[Whelenon]

I don't like what Saturn is doing with the Grendel II and I would think twice about buying one of their barrels. That said, for hunter it should be fine but I would highly recommend measuring the chamber for each bullet to determine your max COL. Even without all the Grendel II BS, I've been measuring my chamber as part of my reloading SOP.

[zbay]

Please pardon my ignorance on this subject I've never really got into the technical details of chambers, and throats. I understand that different guns like different ammo and perform better with said ammo. In your opinion will the Grendel II not run factory ammo as advertised? Do you think the modifications made by Saturn will effect accuracy or long range capabilities?

[JASmith]

This should at least partly help answer your question:

stokesrj, whose opinion I deeply respect, has shot both chambers extensively, and if I recall his old posts correctly, he has found that both chambers shoot well, provided you select the best bullet for that rifle.

If you want ULTIMATE accuracy with any barrel, you have to work the load and bullet correctly.

I believe that the compound throat allows you to shoot more bullets with reasonable accuracy, as LR1955 has pointed out. Bill Alexander and Arne Brennan did a lot of work to find that chamber and for good reason. At one point I shot every single factory load into sub MOA groups with a SAAMI chamber. I suspect that I could repeat that with my SAAMI Grendels now.

I already know that I can't do that with the LBC 264 Black Hole barrel I have, but it does shoot factory Hornady into sub MOA groups and my handloaded Hornady into .75 MOA groups as well. I doesn't like my handloaded 107 Sierras, or 100 grain Bergers. It also won't shoot 123 Lapua Scenars, but that fits what Arne stated above.

Note that the lighter, shorter bullets don't do as well in the LBC and we can infer the same will be true of the "Grendel II" because both have the parallel freebore. That is part of the reason the compound throat exists -- to shoot ALL bullets reasonably well. That 0.5 degree taper in what would normally be a parallel freebore makes a big difference in accuracy when shorter bullets are loaded while still doing very well with the heavier bullets.

These differences mean very little if one is looking for minute of deer.

In the end, know what you are buying or have already bought and develop your expectations accordingly.

[Bwild97]

zbay

In your opinion will the Grendel II not run factory ammo as advertised?

Factory Ammo "should" operate normally in this sub-standard chamber according to the descriptions provided by Saturn.

Do you think the modifications made by Saturn will effect accuracy or long range capabilities?

I would not believe this chamber to be a boon nor a deficit to the 6.5 Grendel cartridge in terms of performance. Quality materials and manufacturing practices are key elements in long range accuracy.

[NugginFutz]

The Geetoo should perform on par with the .264 LBC, and be able to digest any factory ammo. How well it shots depends on what ammo you run through it. My .264 LBC had to be worked fairly hard to get the 123 AMax happy, which eventually ended up shooting well. As I'd previously described, the margin of error was rather small. I recall bwaites having a similar experience with his.

Bottom line is that if you want to eek out the best performance from one, you may have to work at it, as I have. Am I satisfied with my shooter? Absolutely. This BHW polygonal barrel has proven very accurate and stupid easy to clean. Will a Geetoo do as well? I'll never know, but that is another story. Is my .264 better than a Grendel? Perhaps with one or two pills, but I would have to work it, whereas most of the Grendel factory ammo just shoots well through a Grendel's compound throat with little fuss.

Just my .02

[Agshooter]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

[JASmith]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

If you are referring to current factory loads with 120 grain and heavier bullets, then you got the gist of it!

One more time, the challenge will be getting the same tight groups with 100 gr and lighter bullets with the "GeeTo" as one gets with the SAAMI chamber. There seems to be plenty of evidence to form and support that conclusion.

[rickOshay]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

It will be interesting to see if the GeeToo will meet the accuracy of the LBC - given the difference in neck diameter.

My understanding is that one of the reasons the LBC is accurate is because of the tighter neck (@ 0.295) versus the SAAMI 6.5 Grendel (@0.300). The GeeToo has BOTH the wider neck and the parallel lead. So centering the bullet on the bore will be challenging. Again, my understanding is that you would need a high quality barrel to make up for mis-aligned bullets in the chamber. Not going to get that for $200.

Again - it will be interesting to see range reports once people finally get them and shoot them. So far, there's been a great deal of "keyboard claims".

Likely it will be a decent shooter and let people seat long projectiles further out as claimed. And they will likely get another 50 fps higher velocity - see my Post #23 of this thread.

But lesson learned is that if you want a 6.5 Grendel - check with the barrel supplier to confirm that it's SAAMI spec, including the throat. If you want something else, specify that too. People thought they were ordering a SAAMI Grendel, and got something else instead.

[bwaites]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

The 6.5 caliber has a huge range of bullets available, all the way from 85 grain varmint bullets to 160 grain round nose bullets. AR's are almost unique in that they can be extremely accurate, but are gas operated. To find a chamber that would allow the tolerances necessary for semi-auto action (or even full auto!) and still be extremely accurate was the challenge. Bill Alexander ran into accuracy issues trying to make a wide variety of bullets work, until it was suggested that some of the older military chambers had a compound throat and seemed to shoot a variety of bullets well. That compound throat angle apparently centered the bullet, allowing improved accuracy from a chamber that was otherwise tolerant of the necessities of gas operation. The compound throat was developed for the Grendel and by all accounts solved the problem that they had run into with that wide range of bullets. At one point I was able to shoot every factory load, from 90 grain varmint bullets to 130 grain hunting bullets, into sub MOA groups from my first Grendel. That is extremely rare, and led me to believe that Alexander had indeed succeeded. Others have found similar results.

I was able to shoot 2 different handloads into .25 MOA groups with that same barrel. My current 28" Grendel will shoot the 107 Sierra into sub .25 MOA groups, with my best 5 shot group at .18 inches. It will shoot the 123 Factory Amax load sub MOA all the way out to 1000 yards. In fact, I actually shot that rifle in an F Class match at 1000 yards when my usual F Open rifle's barrel dumped on me. On a very windy day, I was the only F Class shooter (in a small field, admittedly) with X's.

You will find very few, if any, traditional chambers that will shoot bullets of such wide range in weight that well.

Given my choice, I would always pick the SAAMI chamber in a gas gun. 2nd choice would be the LBC chamber, which has proven to be accurate with more than one bullet, though it was designed around the 123 Sierra and 123 Amax. The tighter neck (.295) most likely allows for better centering of the bullet in the bore. I actually just finished running a test on a 16" barrel in that chamber and it shot the 123 AMAX well. The last I would choose would be the GII, because it gives away the tighter neck AND the centering effect of the compound throat. Comparing the 3, the I can't find a single advantage in comparison to the other 2.

[ThatRandomGuy]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

As for the actual chamber, I believe bwaites said it best.

For the uproar, it was because a company was putting out non-SAAMI spec barrels, still calling them Grendels, and continued to even after it was shown in several cases they were not. These barrels caused issues with factory ammo (especially the 120ish grain it seemed). Said company blamed the ammo manufacture, and offered to "scrape" the barrels to a wider chamber to accept all types without issue. That scraped chamber is (to my understanding) what they now call the Grendel II. So it was basically people ordered X chamber, got Y as you said, with the main furor being how the situation was put off on others instead of accepted and fixed to the standard originally desired.

[Drifter]

...the main furor being how the situation was put off on others instead of accepted and fixed to the standard originally desired.

Yep.

[babaganoush]

Given my choice, I would always pick the SAAMI chamber in a gas gun. 2nd choice would be the LBC chamber, which has proven to be accurate with more than one bullet, though it was designed around the 123 Sierra and 123 Amax. The tighter neck (.295) most likely allows for better centering of the bullet in the bore. I actually just finished running a test on a 16" barrel in that chamber and it shot the 123 AMAX well. The last I would choose would be the GII, because it gives away the tighter neck AND the centering effect of the compound throat. Comparing the 3, the I can't find a single advantage in comparison to the other 2.

I agree, for the most part, Bill. Where the Grendel opted for a compound throat to keep (all) bullets better aligned to the bore, the LBC went to a slightly tighter throat to aid in bullet alignment. This reminded me of something I read in the not too distant past.

The throat of a rifle barrel is often an overlooked part of the chamber. The throat, however, is very important, especially as related to accuracy. The bullet engages the rifling in the throat. It's critical that the bullet make the transition from case neck to rifling without losing its axial alignment. It's possible for a bullet that is concentric with the bore while in the case neck to enter the barrel misaligned because of a sloppy throat. An oversized throat can allow the bullet to become distorted or canted as it enters the rifling. As a result the bullet will not be spinning around its center of form and has yaw while still in the barrel. When the bullet leaves the muzzle it will yaw even more, causing greater dispersion on the target than would otherwise be seen.

This information, not surprisingly, is found on one of the country's most respected barrel maker's site, Lilja Precision.

http://www.riflebarrels.com/articles/50c...50_bmg.htm

While written in the context of the 50, the fundamentals are the same.

Where I disagree with you is on the cause/effect relationship between the chamber and case neck. While I acknowledge your use of the words "most likely", I believe that without the Grendel's compound throat, it is more likely the case shoulders which provide bore alignment. The tighter throat will allow less deformation or off-axis movement on the part of the bullet.

The other benefit to the LBC's tighter neck is that the brass is worked less during resizing, though not a concern to those who shoot factory ammo, exclusively.

So, either way you look at it, the LBC has the potential to be more accurate than a similar chamber with a sloppier neck, the Grendel and its compound throat not withstanding.

[cory]

So it sounds like the GII is no worse or better than the Grendel chamber, and similar to LBC. So why all the uproar? If it was "I bought a barrel expecting X chamber and received Y" I get that.

Other than that, i dont see the issue. Am I missing something?

To put it simply, a company was producing non SAAMI barrels and advertising them as SAAMI spec Grendels.

Now for the kicker. It was found that some of these barrels were potentially catastrophically hazardous to the user. When the company became aware of this, they denied all fault and blamed the ammunition manufacturers. (Hell if the POTUS can just blame someone else then why can't they?)

Per MIL-STD-882E
Catastrophic: Could result in one or more of the following: death, permanent total disability, irreversible significant environmental impact, or monetary loss equal to or exceeding $10M.

[tango29]

Good deal, wave, and that's what it's all about! Hope the rest can finally move on as well.

John

Amen to that. It is getting old. We as group have in my estimation proffered at least 1000
posts on this topic and all we have done is agreed to do disagree. My suggestion is to only
deal with ethical companies that supply exactly what you ordered and are expecting.


Let the buyer beware.


Lets hope people can move forward and discuss other more interesting aspects of the Grendel. We have beat this topic to death. May I suggest the moderator lock any
current and future posts that refer to the bad throats. This topic is making me throw up.




Just my .02 worth

[NugginFutz]

Lock this thread! Lock this thread! Attica! Attica!

[tango29]

Lock this thread! Lock this thread! Attica! Attica!

10-4 Good buddy.

[LR1955]

OK Guys:

Enough of this one for now. I will see Bill Waites tonight and if he wants to unlock the thread, he can.

LR1955