6 groove vs. 5 groove Old 6.5cm vs new 6.5cm

[MisterYuck]

6 groove vs. 5 groove Old 6.5cm vs new 6.5cm
I was going over the spec sheets for the Ruger American Predator in 6.5 creedmore, trying to decide should I get the older one with the rotary mag that has a solid reputation for accuracy, or get the newer model with the AI style mag. In the specs, I noticed that the older model has 6 groove rifling and the new model has 5 groove rifling.... Hmmmmmm... What is the difference I thought. So I sent an e-mail to Ruger last week, hoping for an answer to that question, pros and cons to the 6 groove (older) vs. the 5 groove (newer) but alas a week has gone by with no response. So, I am asking you fine people. What if any, are the advantages. I was so ready to pull the trigger on a new Ruger American Predator in 6.5 creedmore but I want to get the potentially better unit. Any thoughts? I don't really care about the magazine. I have a rotary mag in my Ruger American .30-06 and have never had a single issue with it. Speaking of .30-06 Ruger has a new American line in "Go Wild Camo". This .30-06 in the "Go Wild Camo" has a heavier threaded barrel like the predator line and instead of the 6 groove rifling like my "plain ol'" American .30-06, it has the 5 groove rifling. My 6 groove gun is (at least in my opinion) very accurate.
Thoughts anyone?

[taylorce1]

Honestly it doesn't matter how many grooves a barrel has. The military has often used two groove barrels, and I have a Pac-nor Super Match that's very accurate and only has three grooves. The last custom barrel I ordered I went with a 1:7 5R twist barrel, I did this because of how well my 5R barrel shot in a cheap T/C Venture rifle.

I think going to the Accuracy International style magazines was a good move by Ruger, but their smartest move was using AR15 magazines for .223 and others. I never had a problem with my American in .300 BLK, but there have been many reports of issues with that cartridge.

[bedlamite]

I had a link to a study on this a while back, but it's lost in my bookmarks somewhere. Basically 5 or 3 grooves requires less force to obturate the bullet than 6 or 4 grooves does, producing less drag in the barrel and consistently higher velocities.

[fourbore]

I believe the idea is that an odd number of lands is better than even. That way as the bullet is deformed going down the barrel the bullet gets engraved by a land directly opposite where is can flow into a groove.

That would make 5 better than either 4 or 6. I can see the logic. How it would actually relate to a Ruger barrel, I dont believe it matters. Not on a Ruger. Hey, "5 R" sounds cools, right? Why not, how could it hurt?

The accuracy will be a based on the quality of the barrel, not the number grooves. If you get into some multi $1000 super duper barrel, sure, the theory sounds reasonable. But for Ruger - no way it will make any measurable difference. I don't believe.

Bottom line, dont be afraid of 5 grooves.

[old roper]

This is what 5R means

These barrels have 5 grooves, and the lands have angular sides.

[Tallest]

FWIW - I have Ruger American 7mm-08 with a 6 groove barrel and a Ruger American Predator 223 with a 5 groove barrel. Shooting the same brand a line of ammo (Federal Fusion), both are very accurate. If I do my part 100%, I can put 3 of 5 shots on a 1" bulls eye at 100 yds wit the other 2 mickey mousing the circumference of the 1".

[std7mag]

No grooves..
Like polygonal...

[MisterYuck]

Thanks for the thoughts and input guys. My son and I have a 5 groove Ruger American Predator in 6.5 Creedmoore on layaway now... Now, to decide what glass to go with. Been looking ar Nikon Black in 6-24X50 or Nikon Prostaff 5 in 4.5-18X40.... I have already decided to go with a Warne steel 20 moa base and Warne Maxima rings.

[Woodsbum]

Bought a T/C compass in 6.5 cm, has the 5 r rifling. Most accurate rifle I have.

[taylorce1]

Originally Posted by MisterYuck

I have already decided to go with a Warne steel 20 moa base and Warne Maxima rings.

Not that I'm against using Warne, it's a great product. I'd save some money and buy some Burris Signature Tactical rings, they will give you up 40 MOA of cant with the ring inserts alone.That way you can use the factory base that comes on the Predator rifle.

[BeeShooter]

It doesn't matter how many grooves you have. 3 to 6 will work the same. On my 6.5cm I've got a 5r. The 5r is supposed to be easier to clean but I can't tell the difference.

[RC20]

Its all in the barrel quality not the groves.

A good 4 grove is as good as a good 5R grove, Polygonal or Pentagonal barrel (that has to be next) .

All the stuff about forces and bearing and pressure is hype.

If you have a quality process you get a quality barrel.

Even the two grove barrels were accurate enough.

[old roper]

I don't think anyone claimed better accurate, even Boot Obermeyer has never said that and he owned 5R name.

I have 2-30-06 one has Bartlein 5R other has Shilen 4 groove Ratchet twist.

http://www.shilen.com/ratchetRifle.html

[RC20]

Whats the point of more work and no more accurate?

[old roper]

RC20, who you posting to.

[RC20]

Old Roper, thought it was obvious

[old roper]

RC20, I sure didn't know loading for couple 30-06 was considered work. I really have no idea what your posting about.

[MisterYuck]

Okay, Sorry for the delay, but I finally got a reply from Ruger on what was the difference between 5 groove and 6 groove rifling.... Here is their responce:

"Mr. Knapp,

We apologize for the delay. These are both product updates for 2018. 5 groove rifling causes less bullet deformation increasing accuracy potential and generally is easier to clean. The AI magazine provides our customers a new option, but both 6973 and 26973 are available to serve all preferences.

Thank you for your interest in Ruger.

Ruger Customer Service "

Thoughts anyone. We ended up getting the newer rifle, by the way and it shoots good.

[old roper]

Boots Obermeyer been saying pretty close same thing for years.

http://obermeyerbarrels.com/faq.html


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What does it mean when a barrel is said to be a "5R"?