Grendel and 5R Rifling (Haters gonna Hate)

[XcountryRider]

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.

[LRRPF52]

I've been doing research to look further into who is making 5R button-rifled pipes. The only ones I have owned or heard of are always a single-point cut-rifled process. Bore tightness is another variable that has more to do with building pressure and velocity than others.

The MV between 6.5 Grendel and 6.8 SPC is actually a lot closer than has been advertised. When you compare a 16" Grendel to a 16" SPC with factory loads for both, they are the same. We have been told that we need 24" barrels to get any kind of velocity with the Grendel that will compare with the 6.8 SPC, but that line of thought has been proven false. Even if you do start 150fps slower, the BC catches up to the 6.8 quickly. For example, you need an 18" 6.8 to be competitive with a 14.5" Grendel for maximum effective range (twice what 95% of all hunters are capable of anyway).

[XcountryRider]

You maybe on to something with the bore tightness combined with the button 5R.

[Tedward]

You maybe on to something with the bore tightness combined with the button 5R.

Now you guys saying this it seems almost obvious that there is a better seal for added pressure.

If you think about the angle of the land to the bore, it is more sloped, less angle. With that the bullet can seal better. Think of a balloon in a square box. When you blow it up the inside corners don't touch the balloon. If it were in an Octagon shape the slopped edges would let he balloon get closer in the corners and have more surface and less gap.

Just a thought if the bullet seals in the barrel and lands better causing more pressure to build up, I guess more velocity with the 5R..

[bwaites]

Why do you think the AR Stoner barrels are 5R barrels?

The only true 5R barrels I've ever seen advertised were cut barrels, but it would be interesting if someone is making buttoned 5R barrels. Midway doesn't mention that they are 5R, and if they were I'd think it would be a great advertising!

Stoner barrels have been made by at least 2 manufacturers according to internet sources, first by ER Shaw, then by Liberty, which is Satern Manufacturings line of button rifles barrels. No one knows who is making them now, but it has been rumored that they've gone offshore.

[Ridgerider]

Why do you think the AR Stoner barrels are 5R barrels?

The only true 5R barrels I've ever seen advertised were cut barrels, but it would be interesting if someone is making buttoned 5R barrels. Midway doesn't mention that they are 5R, and if they were I'd think it would be a great advertising!

Stoner barrels have been made by at least 2 manufacturers according to internet sources, first by ER Shaw, then by Liberty, which is Satern Manufacturings line of button rifles barrels. No one knows who is making them now, but it has been rumored that they've gone offshore.

Lets not go down that road again most of those informed members have a very good idea where they are coming from and its not offshore and those that have used the AR Stoner barrels of late are well aware of the 5R rifeling. Also have a 300 blackout barrel from one of the mentioned companies and that also is 5R rifling

[Tedward]

Why do you think the AR Stoner barrels are 5R barrels?

The only true 5R barrels I've ever seen advertised were cut barrels, but it would be interesting if someone is making buttoned 5R barrels. Midway doesn't mention that they are 5R, and if they were I'd think it would be a great advertising!

Stoner barrels have been made by at least 2 manufacturers according to internet sources, first by ER Shaw, then by Liberty, which is Satern Manufacturings line of button rifles barrels. No one knows who is making them now, but it has been rumored that they've gone offshore.

It is pretty easy to read, its stamped into the barrel.

[XcountryRider]

Why do you think the AR Stoner barrels are 5R barrels?

The only true 5R barrels I've ever seen advertised were cut barrels, but it would be interesting if someone is making buttoned 5R barrels. Midway doesn't mention that they are 5R, and if they were I'd think it would be a great advertising!

Stoner barrels have been made by at least 2 manufacturers according to internet sources, first by ER Shaw, then by Liberty, which is Satern Manufacturings line of button rifles barrels. No one knows who is making them now, but it has been rumored that they've gone offshore.

They are made by liberty barrels and probably never were ER Shaw. The admin at beyond556.com taked to Steve Saturn who called him about erroneous posts saying they were made my ER Shaw and asked him to correct the info on his forum. That was just a couple months ago. They are clearly stamped 5R right on the barrel so no mystery.

[XcountryRider]

These AR Stoner barrels really love the 120g Barnes. You can get 2700fps from a 24in barrel with 28.8 to 29.1gr of AA2520. I'm using 29.3 to to get my gas system working in good order on my 18in barrel but for velocity sake i could be down at 28.8gr of AA2520. The extra velocity really puts the 140gr pills into play as well. They are a little on the porky side and not as accurate at the high end custom rifles but do pretty darn good for the price tag.

[kamrr4437]

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

[XcountryRider]

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

You are correct i edited my post.

[kamrr4437]

lol im just yanking your chain man. I liked your video on youtube for ya. I posted a question on there though. In your comparison are both barrels the same twist rates?

[XcountryRider]

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

[XcountryRider]

lol im just yanking your chain man. I liked your video on youtube for ya. I posted a question on there though. In your comparison are both barrels the same twist rates?

Yes all three AR Stoner barrels chronyed are 1/8 twist.

[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.

I buy Beowulf Barrels from a guy who works for Liberty and are 12.7x42, the same as the AR-Stoner 12.7x42 Beowulf. Also the same Heli-Port Muzzle Breaks for $40, but they call them blems because they have a few pits.