Grendel and 5R Rifling (Haters gonna Hate)

[Tedward]

Notice the Saturn/Libery Muzzle Breaks are the exact 6.5mm Grendel AR Soner Muzzle breaks. Here's the thread where Steve Saturn said they make the barrels.

Oh sweet, I made history, I knew it would pay off...

[XcountryRider]

I can't wait for your to get your AR Stoner (US Made) Libery barrel cronyed Tedward. We'll call it the 2650fps club those that have a barrel that can send out a factory 123 Amax at 2650 fps or above

[rickOshay]

My 24" Satern cut rifled 5R barrel gets normal velocities. So I am leaning toward the tight bore theory to explain the AR Stoner results, not because of the 5R rifling.

[bwaites]

Thanks guys! We've wondered about those barrels for a while. That does explain, to some extent, why people have been so happy with those barrels.

[XcountryRider]

My 24" Satern cut rifled 5R barrel gets normal velocities. So I am leaning toward the tight bore theory to explain the AR Stoner results, not because of the 5R rifling.

Your Saturn is of course using cut 5R vs button 5R if that makes a difference.

[Ridgerider]

My 24" Satern cut rifled 5R barrel gets normal velocities. So I am leaning toward the tight bore theory to explain the AR Stoner results, not because of the 5R rifling.

Think you will find your Saturn barrel is a cut rifled 5 groove barrel and not 5 R rifling. It will be marked 5R on the barrel if it is.

[rickOshay]

Here's the stamp on my Satern barrel:

[Nukes]

...AR Stoner barrels are the Midwayusa brand and are made by liberty barrels and come with 5R button rifling.

Our Grendel has a Krieger 1-8.5" 5R.

[joker31]

bill saturn i thought the owner of Satern was Steve Satern?

Actually the owner is Deb Satern, Steven's Wife. I know almost everyone at the company, talked to deb last week.

And not all Satern's are marked with the specs, Mine is a custom 1 off and is only marked with Satern and a serial number on underside and 6.5 Grendel 1-8.75 on top But the Machinist Print I have says 1-8.75 5R Cut Rifling.

I was always told that the reason a 5R barrel is a little "Faster" is because the bullet seals a little better due to the unopposed Lands. (Lands are 180deg from grooves, not half land half groove like in 4 twist barrels) at least thats what it said in my Forensics text book, it said that the reason its superior and used by Marksmen is due to the fact that it seals the bullet without deforming the core like conventional rifling. Or something like that. Will look for my text book if anyone really cares. Was a class in Applied Forensic Ballistics. Basically how to recreate the origin of projectiles from very far away. now I guess they use computer models.

[kamrr4437]

Well they are married so both own the company lol. But yes you are correct Deb is the owner. I love there company. They make a fine product. They are good people.

[woohoo]

This conversation has been spread out over a couple threads so i decided to consolidate the conversation. To sum up 5R rifling is providing higher velocities with the grendel. 5R rifling doen't have the 90 degree angles which means higher velocities and less copper fouling.





Hornady 123 Amax measured from my and a friends 24in AR-Stoner barrels has a MV of 2650fps vs 2580fps quoted by Hornady. Out of my 18in AR Stoner i'm getting 2560fps. Thats about what you would expect from a typical Grendel with a 22in barrel.

One of the main criticisms of the Grendel usually levied by the 6.8SPC crowd is lower MV but as you see the 5R rifling gives the Grendel at least a 80fps boost. Now you can both get good muzzle velocities and long legs and good accuracy. The faster the load the more performance boost you'll notice. When your shooting the lower grain pills like the 100gr and 95gr fast you can see as much a 150fps boost. I've cronyed 3 AR Stoner rifles now with factory Amax and all three are shooting much faster than other Grendels with the same ammo. 6.5mm pills are longer and have larger surface area that contacts the rifling. Therefore 5R rifling is going to benefit the Grendel more so than shorter fatter calibers like the 6.8SPC.

AR Stoner barrels are the Midwayusa brand and are made by liberty barrels and come with 5R button rifling.

What load are you using to push a 123 to 2650fps out of a 16" barrel?
The photo of the button you posted is really a Hybrid 5R like we use. An Obermyer or Rock has a different land shape, angled but different than shown.
On the same page you took that photo from but further down the page-
.
I have not bore scoped a Satern to see if it is like the Obermyer or if it is a Hybrid. There were posts on the old Grendel forum as far back as 2007 showing the velocities possible with 5R barrels but it is more than just the shape. Bore area, groove diameter and land to groove ratio all play a part in accuracy, pressure produced and velocity. Tweaking all of those can get you a barrel that is much faster but not so accurate or super accurate and a little higher pressure, just depends on what is more important to the person designing the button.
Maybe Bill A. can chime in but it looked to me like the less expensive AA barrels may be a 6R. I didn't spend a lot of time with it or video it but through the borescope the lands looked like they had sloped sides.
These are MAX loads in my 264 5R barrel with a .100 freebore. Some of the max loads shoot 1 MOA easy enough if that is good enough to hunt with. To find 1/2 MOA most need to be dropped 1/2 -1 gr.

123AM 2.3 748.. 31.5 2643 CCI450 20" max charge
123AM 2.3 335.. 29.5 2672 CCI450 20" max charge
123AM 2.3 4895 29.5 2650 CCI450 20" max charge
123AM 2.3 530.. 28 2682 CCI450 20" max charge
123AM 2520 31 2660 BR ........20" max charge

[Dan]

Customer service at Satern told me that Steve doesn't do anything but 5R rifling.

[XcountryRider]

What load are you using to push a 123 to 2650fps out of a 16" barrel?
The photo of the button you posted is really a Hybrid 5R like we use. An Obermyer or Rock has a different land shape, angled but different than shown. I have not bore scoped a Satern to see if it is like the Obermyer or if it is a Hybrid. There were posts on the old Grendel forum as far back as 2007 showing the velocities possible with 5R barrels but it is more than just the shape. Bore area, groove diameter and land to groove ratio all play a part in accuracy, pressure produced and velocity. Tweaking all of those can get you a barrel that is much faster but not so accurate or super accurate and a little higher pressure, just depends on what is more important to the person designing the button.
Maybe Bill A. can chime in but it looked to me like the less expensive AA barrels may be a 6R. I didn't spend a lot of time with it or video it but through the borescope the lands looked like they had sloped sides.
These are MAX loads in my 264 5R barrel with a .100 freebore. Some of the max loads shoot 1 MOA easy enough if that is good enough to hunt with. To find 1/2 MOA most need to be dropped 1/2 -1 gr.

123AM 2.3 748.. 31.5 2643 CCI450 20" max charge
123AM 2.3 335.. 29.5 2672 CCI450 20" max charge
123AM 2.3 4895 29.5 2650 CCI450 20" max charge
123AM 2.3 530.. 28 2682 CCI450 20" max charge
123AM 2520 31 2660 BR ........20" max charge

You missed something those are factory Amax out of 24in barrels.

[woohoo]

You missed something those are factory Amax out of 24in barrels.

oh, I thought you said you were getting the same velocity with handloads as they were getting with 6.8 handloads.

[XcountryRider]

oh, I thought you said you were getting the same velocity with handloads as they were getting with 6.8 handloads.

Awe no the 6.8 folks are still beating us at MV just with these AR Stoner/liberty barrels we are doing pretty decent in the MV department with 80 to 100fps more with factory ammo for the 123gr Amax. We can also get handload 140gr pills going at 2450fps as well.