Types of rifling in BR competition?

3

338lm

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Are conventionally rifled barrels (with the 90° land wall) still the mainstay in BR competition or are there shooters out there using 5R barrels? Can the premium grade cut rifled 5R barrels shoot as well as the conventionally rifled barrels? Any advantages/disadvantages to staying with the 90° land wall versus an angled wall or a wall with a radius blending into it?

Is the jury still out on the advantages/disadvantages of even versus odd number of lands? Any kind of knowledge on even versus odd number of lands will be appreciated also.
 
You might find Kreiger's analysis interesting.

http://www.kriegerbarrels.com/5_R_Rifling-c1246-wp6676.htm

Could be TIm North (current owner of Broughton) might dispute some statements, you'd have to ask him.

FWIW, we have had a couple Broughton (Tim North) 5-R barrels that let us shoot higher velocities at what appeared to be the same pressure. This in big stuff, 6 Ackley.
And one that didn't, in .30. One of the most accurate barrels I ever had was a 3-groove PacNor (.30), which while not having a "5-R" pattern, did had a different land profile. Finally, A Shilen Ratchet rifled 6.5 let me use more powder, with a bit higher velocity, than the previous barrel.

One guy, very few barrels. Sample size way to small to mean much. If there are any advantages, they are so small as to be overshadowed by other factors -- some of which we obviously don't even know yet.
 
While canted land, five groove barrels have an excellent reputation for applications where longer, heavier bullets are used, my experience with two, for my 6PPC, one and one buttoned, has led me to conclude that I will not purchase another for this application. It comes down to this. I believe that the most common powder in use for light bullet 6PPCs is 133, which seems to like some pressure build just as the powder starts to burn. It has been my very unscientific observation that on these barrels the force needed to start a patch is less than my other barrels. Guessing that this may reduce the peak pressure generated by engraving bullets,,and after some frustration trying to shoot loads that were in the range that my conventionally rifled barrels respond to, I decided to try upping the pressure the old fashion way, by tipping the powder can (increasing the charge). This seemed to work (on the cut barrel), but getting the charges in the cases is a pain, and I can see no offsetting advantage to specifying this rifling form for this application. These results are not unique. The cut barreled manufacturer has developed a more conventional rifling for this use, based on feedback that they have gotten that was consistent with that that I gave them. I should also mention that for .30 BRs they make one of the hotter barrels currently in production, and I think they are 5R, but we are talking a different caliber and different propellants. The buttoned barrel was furnished with a .2432 groove diameter, which did not make me very happy and the feel of the patch changes in front half of the barrel, feeling slightly looser for a bit. A phone call to the maker about the groove diameter produced no satisfaction. Not going there again. On the other hand, if I decide to try a 30 BR, I will definitely give the cut maker a call, based on the excellent results others have had.
 
There was serious research done on evenvsodd numbers of grooves during the Black Powder days.

After extensive testing the odd number bores proved more accurate than any even numbers except the 6 groove bores.
Multiples of three proved the most accurate either in even numbered like the six grooves or odd number like the three and nine grooves.
Fives and Sevens were very close in performance to the six and nine, and noticably more accurate than a four groove.
I think seven grooves were fairly common for Kentucky rifles. The larger bore sizes received more benefit from a larger number of grooves. Too many grooves led to quicker wear of the bore of smaller bore rifles.

I would figure six grooves to be the practical limit for .30 caliber or smaller if you want a long barrel life.

Three groove barrels worked well and the broad lands were less sensitive to cleaning rod damage. I've seen an old trapdoor breech loader US Army rifle with three grooves, I can't remember which model it was. It may have been a 50-70.
 
Barrel makers make different number of grooves and different land shapes to make you the shooter happy, no other reason. If I am wrong, show me scientific proof. I don't want anecdotal drivel. Tell me, if I were a barrel maker and I knew scientifically that one land and groove or whatever was the best, the only reason to make the others are for sales.
Read Kreiger's message on 5R barrels. They are being truthful and I respect that.
Butch
 
Butch, I generally agree with you about anecdotal drivel, but there are times it is all we have.

For example, I have several chamerings where, as I go up in powder charge, shots don't scatter. What, then, is the maximum load? When I start getting ejector marks on the case head. (And yes, then back off a bit 'till they disappear.)

No sane manufacturer would test this way. With a large, strong, tight-tolerance BAT action and RWS brass, I'm comfortable. I couldn't recommend the procedue, though, and cerainly not in a public forum.

The results of any testing done this way are anecdotal, but may be relevant for the BR community.
 
This is from the Krieger web site, part of the page that the link given above leads to. ** NO twist slower than 1-9 for 6mm barrels are available. Good authority has shown that short, light, 6mm bullets do not perform well in most 5-R™ barrels. We have no knowledge as to why, but do not want to risk an inacurate Krieger Barrel being on the market.

It would seem that their assessment of this land profile, with regard to its suitability for short range Benchrest, is in agreement with my previous post. How many others posting here have actual experience with this rifling form in a 6PPC? The person who started the thread asked a question in an area that I have experience, and I related some information that have cost me several hundred dollars to obtain. Of course I would be glad to hear from anyone that has had different results. Perhaps I can learn how to get better results from my two barrels. In the mean time, I will continue to agree with Krieger.

 
Charles,
I have 2 5R barrels purchased from the same manufacture at the same time. One is as close to a hummer as I have ever had and the other is mediocore. I did not specify 5R and didn't know that they were until putting a borescope to them. I did that after noticing dialing in the grooves was doing funny things.
I think it is back to some barrels for some reason are good and some not so good.
Butch
 
I agree, Butch. As I said in my original post, if there are any advantages, they are down on the list of important things (always shooting real good).

In deference to Boyd, I should note that the barrels I mentioned are for long-range benchrest. I figured since this was the General Discussion, that was good enough.

Specifics, for those who care: Two 6.5 barrels, chambered in 6.5/06 AI, using 140 grain bullets. One mine, (Shilen ratched rifled), one Joel Pendergraft's (Broughton). Both allowed higher velocity than any of our previous 6.5/06 AI barrels. The Shilen shot OK -- I had a 6th at the 2005 Nationals in the 2-gun overall, where this barrel was on my LG. I don't remember Joel's performance. Two .30 barrels, chambered in a case equal to a .308 Norma Mag, shooting 187 grain BIBs flatbase (long bearing surface), both mine, one a PacNor 3-groove (different land profile) that allowed higher velocity, and one a Broughton that didn't. Both are good, but not great barrels.

Small sample size, and used with bullets having a long bearing surface.

FWIW
 
How many lands would you guys recommend for each of the (3) bullets weights? Caliber 6.5x47

1) 120/123 Bergers and Scenars
2) 130 Bergers and Norma's
3) 139/140/142 Scenars, Bergers, Matchkings

I am most likely going to shoot 130's out of this next build. Would a 4 groove or a 6 groove be better with long 6.5 bullets or a 3 groove or 5 groove?
 
I know of no reliable data that shows the number of groves has an effect, for good or ill, with jacketed bullets. That's a different question that the profile of the lands -- though come to think on it, I guess I've never heard of a 5-groove with a "normal" profile. Probably is, though.

There was a bullet maker who lives in Iowa that remarked, with respect to small .30s shooting short bullets, that his experience was 3-groove barrels shot best with hot loads, 5 groove shot fine with hot or mild. I've never herd anyone else offer this comment. And I doubt he'd bet the homestead on it.

In the long-range game, 4-groove barrels win. As do five groove and six groove. And I'd bet if someone had an old .30 two-groove that was hot, it would win too.

If you want "advice'" go look at match equipment lists, and see what barrels the winners are using. Then get one of those. It will likely show fashion rather than feature or quality, but, hey, it can't hurt.

Same goes with land profile. No proof. The only negative seems to be the short bullets. And oh yes, I had some issues with bullet choice with a 6.5 ratchet rifled barrel. I couldn't jam the 140 GTBs, any significant land contact and I got the complete throat "ring" around the bullet. So I used a different bullet.

I use to just keep getting different barrels until I got one that would shoot "my" bullet. Then Lou Murdica pointed out it is cheaper to have several kinds of bullets & test to see which your barrel likes. Smart man.
 
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