Thoughts on preferred barrel blanks barrels with 5 r rifling

Coyote Shadow Tracker

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Interesting. I have went through PBB website and their barrels are "Button Stress Relieved" They describe their drilling, but not much on the rifling process or # lands/grooves. 5R is a 5-groove rifling pattern with sloped or angled sides to the lands. All rifling has a certain amount of angle to the sides of the lands as a natural effect of the rifling process. The sides of the grooves are parallel, but the sides of the lands are not and the 5R Cut carries this to an extreme. Manufacturers are using the "5R" label on both hammer-forged and button-rifled barrels.

The ”R” comes from Russian origin.

5R is an improvement over conventional rifling by changing the shape and configuration of the lands and grooves. Conventional rifling, while effective, can be improved upon in two ways.

  • 1. Conventional rifling has sharp 90-degree corners from the top of the land to the bottom of the groove.
  • 2.Conventional rifling has lands and grooves opposing one another.
5R rifling improves upon this by using 5 lands and grooves over the even numbers which puts lands opposite of grooves. Further, the transition from the top of the land to the groove is sloped.

5R reduces projectile deformation as it passes through the bore during the firing sequence. By placing the lands opposite of the grooves, the bullets are no longer squeezed on opposite sides ensuring the projectile stays uniform instead of squeezing material into the grooves. More uniform projectile means better accuracy.

Secondly, by sloping the transition to the groove, the barrels become much easier to clean. In a conventionally rifled platform, these corners become depositories for lead and superheated materials left after shooting. Cleaning supplies have a hard time reaching these corners as they are incredibly small. By sloping it, cleaning supplies are easily able to get to the deposits.

Does this mean conventional rifling is no good or which is better?

Absolutely not! Conventional rifling has been slinging projectiles accurately for over 200 years and will continue to be used in match and hunting rifles.
 

Muddyboots

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All I look at is their barrels shoot well for me. 5R is well just a feature and I would have older barrels from them that are 6 groove and they shoot well. Is it better? Just another campfire session.
 

JWgroups

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Yep, you will be impressed! I have Bartlien 5R barrels on 308, 6.5 CM, 6 BR, 223 Rem. When it's time to clean, they just don't get as dirty and clean with less effort IMO than the button barrels. Accuracy has been great in all of my 5R barrels.
 

RAGGED EDGE

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In the fall of last year "GUNS" magazine carried a good article on 5R and how Boots Obermeyer brought it to the forefront of barrel making. Article was written by John Krieger. Search "What Is 5R Rifling?"
 

tim_w

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In the fall of last year "GUNS" magazine carried a good article on 5R and how Boots Obermeyer brought it to the forefront of barrel making. Article was written by John Krieger. Search "What Is 5R Rifling?"
Thats because Boots sold all his equipment (Whitney Pratt machines etc) a few years back to Krieger as he had a number of health issues including a stroke. He mainly filled gov contracts for many years and reg consumers got their orders filled if he had spare time which meant very long waits. Sometimes over a year. He was a one man shop and kept his orders in emails. Quite informal by normal and certainly current standards. His main caliber built was 308 11 twist for 308 W chamber. If you were wanting that it usually had the best chance of a turn around. Anything else in a dif caliber could be a painful wait.
 

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