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.
I have an Obermeyer 9 twist 6R on an Ar-15.
We've made 4R style rifled barrels. Don't shoot any better.
Later, Frank
Bartlein Barrels
I tried a Muller 4R as an experiment and it was nothing special and was average at best..... jim
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??
That's what this barrel is. Average at best huh? Just in accuracy or all around?
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.Did "Boots" use 4140 ?
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.