4R rifling?

[InkedIan]

I bought a 7 twist .219-.224 barrel and to my surprise it has 4r rifling (like 5r) instead of conventional 4 groove. Has anyone seen or tried that before?

 

[butchlambert]

Is it a Shilen 4 groove ratchet rifling?

 

[PDS]

I have an Obermeyer 9 twist 6R on an Ar-15.

 

[Dusty Stevens]

Shilen or benchmark?

 

[watercam]

I have 3, 4, 5 and 6-groove barrels in calibers from .223 to 9.3. They all shoot great and clean as easily as any other custom barrel.

 

[InkedIan]

I've seen and used canted land button rifled barrels but hadn't seen or heard of 4R cut rifled. Just thought it was interesting.

 

[InkedIan]

I have 3, 4, 5 and 6-groove barrels in calibers from .223 to 9.3. They all shoot great and clean as easily as any other custom barrel.

Lol, I'm well aware there different number grooved barrels. I'm talking about the trapezoid shaped R style lands.

 

[Joe Maisto]

I have an Obermeyer 9 twist 6R on an Ar-15.

Did "Boots" use 4140 ?

 

[Alex Wheeler]

Broughton did a 4r he called it 4c. Rock creek does a 4h, it's a 4r on one side conventional on the driving side. They shoot.

 

[Will Henry]

I have a couple of four groove with trapezoidal lands barrels. These were hammer forged blanks from a Swiss manufacturer. These barrels shoot very well and clean easily. In other words, they work just like all of my other good barrels. Whether cut, buttoned, or hamered; whether four, five, six, or eight groove, a good barrel is a good barrel. WH

 

[FrankG]

We've made 4R style rifled barrels. Don't shoot any better.

Later, Frank
Bartlein Barrels

 

[InkedIan]

We've made 4R style rifled barrels. Don't shoot any better.

Later, Frank
Bartlein Barrels

Or any worse hopefully!

 

[johara1]

I tried a Muller 4R as an experiment and it was nothing special and was average at best..... jim

 

[InkedIan]

I tried a Muller 4R as an experiment and it was nothing special and was average at best..... jim

That's what this barrel is. Average at best huh? Just in accuracy or all around?

 

[InkedIan]

Excuse me it this sounds stupid... I believe the R stands for rounded (as in not square cut). Since the first thing to wear in a chamber are the edges of the rifling???? Why would you want to give land erosion a head start? Am I missing something?

I know barrel makers would be happier with barrels wearing out faster..... But as a shooter there is nothing worse than a screamer barrel going south faster.

Waiting to be shown the way??

I don't believe the top of the land is rounded. More so the edges with it being sloped towards the base. The slope on the Mueller is less gradual than the bartlein shown. Almost like a blend between conventional and R.

 

[johara1]

That's what this barrel is. Average at best huh? Just in accuracy or all around?

It was a experimental barrel HV. 8 twist wouldn't shoot in .2 at 100..... So what do you think, I have a 7 twist Kreiger 4 groove that shoots in .1 or less and a Brux that is better and two Lederersj that are super..... jim

 

[Whitehunter]

I have Shilen 4 groove ratchet in 30 caliber for my heavy gun. If we ever get to shoot matches again I will let you know how well it shoots. Also a 5R in Krieger. Just need some good bullets and brass. I beat they will shoot small with high scores.

 

[PDS]

Did "Boots" use 4140 ?

I don't know what alloy Boots used for his chrome-moly barrels but he did have them available. I asked for a stainless 5R barrel blank Boots said his .224 barrels were 6R rifling so that is what I got.
Back then in 1988 a 1-9 twist was good enough for the bullets available.

 

[InkedIan]

I'd put my money on it being a Pac-Nor polygonal. Pac-Nor polygonal rifling in larger calibers is really nothing but 6R, at least in appearance. The polygonal rifling I am familiar with typically had the entire land rounded and so was the groove, like a Glock. There is no corners and it looks like it is heavily "worn out".
The first time I barreled up a Pac-Nor barrel I stuck a bore scope in it and thought they sent the guy the wrong barrel. If in fact this is what you have...to answer your question, "anyone seen or tried that before?", yep a few times and it worked out just great without exception. The real question should be, "is there any advantage?? does it shoot more accurately or clean easier??" the answer to both of those is no.

It's a mullerworks cut rifle barrel. It wasn't a special order or anything that's why I was surprised to see the 4R. Didn't think that would be their go to land/groove choice.

 

[swd]

Brux has been canting lands on at least some of their 4 groove barrels for about the last year or so. As I understand they did it to help some of the newer long high bc bullets live in fast twist barrels.