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skeetlee
07-29-2009, 06:06 PM
I hope this is an accuracy related topic!! When i bought my Bartlein 30cal 17 twist barrel blank i noticed it was marked 4groove. I have read very little pertaining to why one would want a 3 groove or a 5 grove or 6 or what ever it may be. Whats to gain or loose with the different groove ratings? I understand that a 5 grove has more grooves in the rifling than a 3 groove, but what does this have to do with anything. I also read that for a 30br most folks want a 3 groove. Why?? I was hoping someone could help me understand why one might be better than another. Thanks guys!! Lee

greg
07-29-2009, 06:23 PM
I hope this is an accuracy related topic!! When i bought my Bartlein 30cal 17 twist barrel blank i noticed it was marked 4groove. I have read very little pertaining to why one would want a 3 groove or a 5 grove or 6 or what ever it may be. Whats to gain or loose with the different groove ratings? I understand that a 5 grove has more grooves in the rifling than a 3 groove, but what does this have to do with anything. I also read that for a 30br most folks want a 3 groove. Why?? I was hoping someone could help me understand why one might be better than another. Thanks guys!! Lee

I don't think its accurate to say "that for a 30br most folks want a 3 groove." I defy you to find anyone who has empirical evidence that 3 is better than 4 is better than 5 is better than is better than 7.....A good barrel is where you find it. Stick with a major supplier and you generally won't be disappointed. I have had 7, 6, 4 and 3 groove and have had good barrels in all groove configs. My best barrel happened to be a 3 groove, but that's probably not because it was a 3 groove. You'll get tons of opinions on the subject but not much else to help you.

Butch Lambert
07-29-2009, 06:36 PM
Lee,
Don't confuse yourself with grooves. Just shoot the damn thing! Do a search if you want to read about grooves. If a barrel is good it don't matter how many grooves it has.
Butch

Big Al
07-29-2009, 07:21 PM
Does it make you wonder how all of the two grove barrels ever shot made by the thousands of .30 cal barrel made for WWII? I have never seen a good or great barrel because of the number of groves. Good is good. End of story.:D

skeetlee
07-29-2009, 07:30 PM
thanks Lynn thats the kind of answer i was looking for. When i am looking for a barrel the groove count is the last thing i am looking at so i dont worry about it and then i just shoot the dam thing!! I was just simply trying to educate myself on why one would want one over the other, thats all!! I didnt know if i was missing out on something. I enjoy discussing these type of things simply because it intrests me. If anyone else has something to add i would enjoy reading it. Thanks Lee

Butch Lambert
07-29-2009, 08:24 PM
The barrel maker will make what ever configuration that sells.
Butch

Dick Grosbier
07-29-2009, 08:42 PM
I just counted up in my head and so far I have owned eight 30 cal barrels in past 5 or 6 years . I can tell you which was good and which was great and even a couple that so far seem poor to mediocre. I cannot tell you how many grooves any of them had.

Dick

jackie schmidt
07-29-2009, 08:58 PM
Thert is a great interview with Tony Boyer in the Aug Precision Shooting.

He has not changed his attitude toward barrels at all. Really great barrels are few and far between. All you can hope to do is get one by pure chance.

In the mean time, we all settle for what are really good barrels. They will be competitive, and will win matches.

It will probably shock most shooters to here Mr. Boyer say that most barrels loose their best at as few as 600 rounds. Sure, you can keep shooting it, but that doesn't change the reality of the situation.

As for the groove thing, I like 4-groove barrels because they are so darned easy to true up in a chuck with a 4 adjustment feature, whether it's a 4-jaw independent or a 3-jaw set true, which features 4 adjustments opposite each other.........jackie

upandcoming
07-30-2009, 02:35 AM
It will probably shock most shooters to here Mr. Boyer say that most barrels loose their best at as few as 600 rounds.

But if the accuracy peak at this level, can we at all have any chance of quantifying by "how much"? I assume every barrel has a different story but the rate of decrease in accuracy, is this only by feeling? Not that I question his comment at all, but on what level do we need to be to know for sure? Being a rookie like me I assume I would never recognise that the barrel peak at that amount of rounds, however knowing that it might happen can surely twist my mind ...

Secondly, and I know this is perhaps not a wise thing to hunt at all, it might not even be cost effective, but could there by anything we can do to breath some extra life into the barrel again? Or said in other words - what is the weak point of the barrel that makes the peak occur around xx numbers of rounds? Do we know or is this also one barrel one story?

Butch Lambert
07-30-2009, 07:20 AM
You might consider having your barrel Melonite QPQ treated.
Butch

mbp
07-30-2009, 08:48 AM
maybe, possibly, a barrel with less grooves, has fewer edges (land to groove angles) .....(which can collect copper,carbon, etc.) and such a barrel MAY be easier to keep clean??? however, all custom barrels I have shoot better than I can, and I clean them all the same, and they all look great in the borescope, and I would not ever turn my nose up at any groove #.

caroby
07-30-2009, 09:09 AM
As for the groove thing, I like 4-groove barrels because they are so darned easy to true up in a chuck with a 4 adjustment feature, whether it's a 4-jaw independent or a 3-jaw set true, which features 4 adjustments opposite each other.........jackie

Yes Jackie, this I too have discovered... Just easier to adjust and get running true.

As far as barrel makers are concerned...

The Button rifler dosen't care. Just one pass of the button and a 2 - 8 groove barrel is rifled.... Now making (grinding) a button with "alot" of grooves is probably more time consuming than one with just two...Stands to reason.

The Cut rifler has A LOT more time in set-up and actual rifleing the barrel when the number of grooves increases.
This is one of the primary reasons why the cut rifled barrel makers stick to 4 groove barrels... They shoot fine and keep the manufacturing process time reasonable.

Good ones are just that.... Great ones are....!:) ... Still looking.

cale

JonE
07-30-2009, 09:27 AM
I probably should keep out of this as I no longer have my reference books, but, one of the early big name barrel makers, I think it was Pope but dont remember for sure said that he felt an odd number of grooves was more forgiving to bullet imperfections. In other words, an odd number barrel was no more accurate than an even number, all other things being equal, but an odd number barrel would shoot less than perfect bullets slightly better than an even number barrel. If his theory was true I would tend to think that with our near perfect bullets today in comparison to his day the number of grooves does not matter

skeetlee
07-30-2009, 02:36 PM
Good read guys i appreciate your response. I still dont know how a certain number of grooves effects the potential accuracy. All in all it sounds like i dont need to know!! LOL!! Man i Love this stuff!!! Lee

JohnVm
07-31-2009, 02:00 PM
I have heard from a few that have tried some two groove barrels that they seamed to be exceptional if you could ream a straight chamber in them as this seemed to be next to impossible without a special button.

Butch Lambert
07-31-2009, 04:03 PM
John,
What does the amount of grooves have to do with a straight chamber? A good chambering method will allow a straight chamber regardless of grooves.
Butch

Kim Merrill
07-31-2009, 06:23 PM
Does the number of grooves effect the velocity? Will 28g of 133 produce the same fps in different barrels?

Mike Bryant
07-31-2009, 08:22 PM
You'll find that the majority of cut rifled barrels such as Krieger and Bartlein are 4 groove barrels. The button rifled barrels will be where you see more or less grooves offered. Krieger and I'm sure Bartlein will make barrels with more grooves. I know Krieger offers 6 groove barrels, but you'll pay more for a 6 groove barrel than for a 4 groove. I've never bought or installed a cut rifled barrel that was anything but a 4 groove. All a button rifle maker has to do to make a certain number of grooves is have a button with that number of grooves and either pull or push it through the reamed hole that matches that button. To go from a 4 groove barrel to a 6 groove barrel, it takes a lot more passes of the cutter down the barrel to cut the extra two grooves. Every groove on a cut rifled barrel is a large number of passes of the cutter down the barrel. A 3 groove barrel would take a wider cutter and probably a lot of retooling. But, when you can sell as many of the 4 groove barrels as you can make and shooters win with them, there's not much incentive to make 3 groove barrels.

Jackie, if you want to see a barrel that's hard to indicate in, try a 9 groove barrel. I had some Harold Broughton .22 barrels that were 9 groove. Tim North still has the button and will make them. I chambered the first barrel and won the 100, 200 and grand with it at the first match I shot it at Luther, then the next month just about did the same thing winning the 200 and grand. I thought I had stumbled on the holy grail. The second barrel never shot as well as the first. Both barrels were made at the same time, both out of the same lot of steel, both were heat treated at the same time, one shot and the other didn't.

Frank Green
08-01-2009, 07:24 AM
This subject has been talked about before and I will recap some and give some of my opinions here.

I've shot two groove barrels thru 6 groove in standard calibers up to .30. I don't see the number of grooves for the most part having any real impact on barrel life or accuracy or in how they clean.

One comment made about a 3 groove barrel lasting longer. This might be true in a button rifled barrels as stated because the lands are wider. I would agree with this only in a button rifled barrel. Button rifling work hardens the bore where cut rifling does not. The wider lands might hold up better in a button rifled barrel.

We've been making most of the match rifle barrels and ammunition test barrels for Norma ammunition for the last few years. On they're match rifle barrels they are getting 4 groove barrels with a 50/50 land to groove ratio. They also get special bore and groove sizes. When I asked why the land to groove ratio and special dimensions (being 50/50 they have a wider land than a standard 4 groove) the comment back was because they are trying to get longer barrel life. These are barrels being chambered in 6XC. So far I've seen or heard nothing to prove they are getting anything longer than a standard 4 groove. They shoot great though.

I do lean towards a odd number groove barrel like a 5 groove (or 5R style) but I feel it is more to do with the odd number of grooves might distort the bullet jacket less. I believe this will help fight bullet failures (this is more of problem with a long range shooter than a short range shooter). Sometimes bullets fail due to problems with the barrel and also the bullets themselves can be a problem. Whey do they fail is a another subject but it might go along with what was said earlier that it helps a bullet with defects or poorer quality shoot better. I've got a conventional 5 groove barrel (not 5R) on my short range bench gun and it is a hammer. I don't see it shooting any better than a 4 or 6 groove. We made a small run of them at the request of some of the bench shooters and I kept one for myself for shooting and testing.

Does it take more time to make a 6 groove vs. a 4 groove etc....for a cut rifled barrel maker? For some cut rifled barrel makers it does take longer in terms of set up than it does us. Places like Krieger etc...in order for them to make a 6 groove they have to add or remove spacers from the indexing plate for the number of grooves they need to make in a barrel. This could take anywhere from a 1/2 hour or longer depending on how smooth the change over goes. Also they need to have a machine that has the proper indexing plate. This isn't a problem for us. We just enter into the machines computer how many grooves we want.

Tooling still can play a part. Normally we and other cut rifled barrel makers use a different tool for a 4 groove vs. a 6 groove etc....but for us if the tool is already made we can just pop it in and go.

From a pure standpoint of rifling time. Yes it takes us longer to rifle. You are cutting 2 more grooves so the barrel is in the machine for a longer period of time.

Number of grooves for the most part shouldn't have any real effect on velocity. I had guys bring this up before and I don't see any difference. I've had guys try and tell me that a 5R rifled barrel vs. a 4 groove you get 200 - 400 more fps. Well we made a 5R barrel with the same bore dimensions as my 4 groove used the same chamber reamer, ran the same loads and bullets thru both of them and the barrels where the same 30" finish length (for a 1000 yard prone gun). Guess what the difference in velocity between the two was 30fps. That small of a velocity difference does not really show anything and to me is just the individuality between two barrels. Also I've seen no real difference between a two groove and 4 groove .30cal. barrel or any real difference between a 4 groove and a conventional 5 groove barrel in 6PPC chamber.

Later for now, Frank
Bartlein Barrels

jackie schmidt
08-01-2009, 09:19 AM
Remember back when I shot that 25 BR in the 90's. Well, the best barrel I had for that project was a 13 twist 8 groove Shilen. I had got that barrel blank from Glen Newick, I think he had bought it back in the 80's.

That was still one of the best barrels I ever owned, period. I gave it to a friend, and he still has it screwed onto a Remington Action. Gosh knows how many rounds went down it........jackie

caroby
08-01-2009, 10:11 AM
Great reads..Hu Lee..!
Thanks Frank ..!
Still just amazes me how the Top barrel makers lap there barrels SO consistently..... BY HAND and Feel...! LOTTSA experience and toil..!;)

cale

skeetlee
08-01-2009, 11:19 AM
Thanks Frank for your time!! I am glad i have one of your barreles for my 30br adventure. I am really pumped about this build. More so than any others i had done up to this point. Again, thanks fellas i always enjoy reading what you guys have to say. Lee

Big Al
08-01-2009, 04:55 PM
I thought long and hard on the number of match grade Springfield and sniper rifles that had two grove barrels. Now I'm pretty sure they were mounted on these WWII receivers because they tested to be accurate?

I don't know, but one of the HART brothers worked for Remington during WWII where they made the first buttoned rifle barrels. I always figured Hart made button rifled barrels after the war because of what was learned at Remington?

I don't think that any maker makes and sells a two grove today, lack of demand from the public, I suppose. But the ones I've shot were not but anything but good barrels.

Kent Owens
08-01-2009, 05:35 PM
Benchmark makes 2 groove rimfire barrels. I put one on a 40X rimfire rifle a couple of weeks ago. I don't know if they make them in other calibers or not. They make great rimfire barrels and are great folks to deal with as well.

JohnVm
08-02-2009, 07:23 PM
John,
What does the amount of grooves have to do with a straight chamber? A good chambering method will allow a straight chamber regardless of grooves.
Butch

Butch, my understanding of it was that with only 2 lands there was little support for the reamer button where the grooves where. I can picture it better than I can describe it, but 3 or more grooves should be much more supportive in holding the button centered if the bore is concentric or perfectly round. Sort of like a three legged stool or a 2 legged stool.:)

Butch Lambert
08-02-2009, 09:30 PM
Johnvm,
If your setup is good you don't need a button.
Butch

Kent Owens
08-02-2009, 09:36 PM
JohnVM
2-groove chamber- With a reamer with the proper sized pilot and the barrel dialed in to run true it's not as hard as one would think. It'd not an issue, but some folks can screw up most anything if given a chance.
However, if the barrel was running out and the reamer was held rigidly in a holder of sorts, it'd be possible to screw it up, just as is the case with any other chamber.