How many grooves?
- Thread starter AndyW
- Start date
LOL, I resisted the urge to post on this thread because I wanted to see some responses first. Most of the points that have been accrued by all the shooters in the BR Hall of Fame,by a long shot), have been earned using 6 groove barrels,Hart and Shilen). The #1 barrel today on the line at BR matches is a 4 groove Krieger, and 4 groove Bartleins are seen in big numbers now also. IMHO, I don't really think it matters how many grooves a barrel has, when it comes to accuracy potential. I also see no evidence that a 3 groove, or 4 groove, or whatever will foul more or less than another, or that pressures will be any different with one versus the other. The key is an extremely uniform barrel with a concentric chamber job and crown.
I just made a big posting on this subject a couple of days ago on benchrest Central. Go over and take a look at it. It's too long winded to rewrite it here.
It's under forums and then under 1000 yard benchrest about half way down on the first page.
Later, Frank @ Bartlein Barrels
It's under forums and then under 1000 yard benchrest about half way down on the first page.
Later, Frank @ Bartlein Barrels
Frank, I was wondering if you would post on this subject. You and I traded emails on this subject recently, but the underlying theme had to do with tuning..do you remember? Anyhow its good to have one of the top barrel makers chime in with their expertise on these subjects. BTW guys, if you haven't tried Bartlein yet, you don't know what you are missing. I chambered 10 or 12 of them last year and couldn't be happier with them.
O.K. Tightneck this one is for you. It's a long one!!! I might bounce around a bit so bear with me. I will be talking about barrel life and accuracy both because they go hand in hand. That's why I will probably be bouncing around or have things in no particular order. I'm not a english major!
The number of grooves? To me the number of grooves has no real bearing on accuracy or barrel life! Some say if you want hard core accuracy go with conventional rifling vs. 5R type rifled barrel. Some say the 5R's copper foul less. I say B.S. I've seen 5R's copper foul with the best of them. Some say the 5R barrels will seal the bullet better in the bore and you get more velocity out of them. Again I haven't seen this either. Some say the 5R barrels don't leave a burr on the bullet and the bullet will drift less in the wind. I haven't seen this either.
99% of the barrels we make for short range bench shooters are 4 groove conventional rifling.
Across the course high powers shooters seems to be a 50/50 split.
Long range prone shooters seem to prefer the 5R.
Long range bench shooters I would say the preference is towards conventional rifling.
I've got a conventional 5 groove,not 5R) on my short range bench gun. Wanted to try it! The gun hammers!
I've shot 5R and a 4 groove in prone matches out to a 1000 and even compared both in the same match,two man team) and saw no difference. Our team came in 3rd for points. Same chambers, same loads! Both guns we're chambered in 6mm Rem. with a custom throat. In that match we shot 107 Sierra's,I've shot mostly Berger 105's after that). Both are 1-8 twist barrels. Velocity difference between the two was 30fps. The loads average 3155fps. between the two. We didn't use anymore or any less windage on one gun vs. the other!
Some will say the odd number of grooves will help with jacket failure? This is because the odd number of grooves vs. an even groove barrel will distort or upset the bullet jacket less. This is because the lands don't directly oppose one another. I believe this has some merit but it is hard to prove. Read the next paragraph though.
I compared a 5R and a 4 groove in the match at a 1000yds. the match I mentioned earlier. The 4 groove was the second barrel in a row that I had when I was at Krieger that would blow up one manufacturers bullets but not another. I stopped shooting them for awhile because I was to scared to use them.,Who the bullet makers are is not important. I still shoot they're bullets!) So I wanted to see what would happen. Bought some more of those one makers bullets and guess what. No failures in either one. So in away that kinda blows the theory!?
Both barrels we're made to the same bore and groove size and same twist. Same chamber and the same loads shot thru them. Why didn't the one barrel blow up anymore of the one makers bullets anymore? I chalk it up to a different lot. Maybe the lot of bullets I got had problems with the cores or jackets? Hard to say!
Barrel life? Again I don't see a difference in the number of grooves effecting barrel life etc...One barrel maker who is making 3 groove barrels the last I heard was claiming they last longer. This might be true in a button rifled barrel because of the wider lands. On average I don't see a button rifled barrel lasting as long as a cut rifled barrel. Why?
Because the button rifling operation work hardens the bore. I'm not saying a button barrel will not go a long time or a cut barrel will not burn out early as I've seen both. It's just what we see as an average. Can I put a number on it. Not really but if I had to I would say about 20% longer on cut barrels but this all depends on the accuracy level each individual shooter wants/needs, how good they are not to mention a whole ton of other variables that effect barrel life. One guy shoots a powder that is more abrasive than another is an example. Not to mention the steel from one lot to another even if you are getting the steel from the same supplier can be a variable. The list doesn't stop almost.
When we we're at Krieger back around 2000 Tracy made the tooling for a 3 groove .30cal. palma barrels and we made a couple for Mid Tompkins. Mid told me that accuracy wise out to 800 yards they shot just fine compared to the 4 grooves. The only problem was both barrels we're a flat 100-150fps. slower than the 4 grooves so they wouldn't cut it at 900 and a 1000 yards. due to the velocity loss. Why? Maybe because of the wider lands? Different lot of steel? Hard to say sometimes but that is my guess the wider lands.
Also at Krieger right before we we're gone from they're we made a cut rifled barrel and a button rifled barrel in .224 cal. for John. He chambered them up in .22-250 and put them on some prairie dog guns that he took out west. They we're made out of the same lot of steel and got the same loads thru them. Accruacy wise both shot great but the button barrel was exhibiting more wear with the same round count on both. Both barrels we're being shot in the same conditions and the same loads we're being put thru them.
I've seen 2 groove, 3's, 4's, 5's,5R's) and 6 groove barrels all shoot excellent. So again I say there is no difference in in accuracy or barrel life but when you compare one or the other you should be comparing/testing the barrels made out of the same lot of steel and being made from the same maker and being shot in the same conditions. This is the only way to get good results but who has the time, money etc...to do this? This is the hard part.
Check out the thread records fall at Sacramento. Craig St.Clair shot a 1-8 twist, 4 groove, .237 bore at 600 yards chambered in 6BR. He won 7 out of 8 awards and has 2 pending records. It was smithed by Stu Harvey.
In the end to me it is more of the quality of the barrel blank. The straighter the barrel, the more uniform the bore and groove dimensions, and the more uniform the twist the more forgiving the barrel is going to be. The nicer the finish inside the less fouling it will have etc....
Keep in mind there are alot of variables beyond the barrel maker and gunsmiths control and even the shooters control. What chamber reamer was used. Different lot of bullets from one to the next, different lot of powders, primers, cases etc...all effect different things. Why is one barrel faster than one vs. another. Why does one barrel that looks glassy smooth foul bad and it shouldn't etc................
Talk to you all later, Frank @ Bartlein Barrels
The number of grooves? To me the number of grooves has no real bearing on accuracy or barrel life! Some say if you want hard core accuracy go with conventional rifling vs. 5R type rifled barrel. Some say the 5R's copper foul less. I say B.S. I've seen 5R's copper foul with the best of them. Some say the 5R barrels will seal the bullet better in the bore and you get more velocity out of them. Again I haven't seen this either. Some say the 5R barrels don't leave a burr on the bullet and the bullet will drift less in the wind. I haven't seen this either.
99% of the barrels we make for short range bench shooters are 4 groove conventional rifling.
Across the course high powers shooters seems to be a 50/50 split.
Long range prone shooters seem to prefer the 5R.
Long range bench shooters I would say the preference is towards conventional rifling.
I've got a conventional 5 groove,not 5R) on my short range bench gun. Wanted to try it! The gun hammers!
I've shot 5R and a 4 groove in prone matches out to a 1000 and even compared both in the same match,two man team) and saw no difference. Our team came in 3rd for points. Same chambers, same loads! Both guns we're chambered in 6mm Rem. with a custom throat. In that match we shot 107 Sierra's,I've shot mostly Berger 105's after that). Both are 1-8 twist barrels. Velocity difference between the two was 30fps. The loads average 3155fps. between the two. We didn't use anymore or any less windage on one gun vs. the other!
Some will say the odd number of grooves will help with jacket failure? This is because the odd number of grooves vs. an even groove barrel will distort or upset the bullet jacket less. This is because the lands don't directly oppose one another. I believe this has some merit but it is hard to prove. Read the next paragraph though.
I compared a 5R and a 4 groove in the match at a 1000yds. the match I mentioned earlier. The 4 groove was the second barrel in a row that I had when I was at Krieger that would blow up one manufacturers bullets but not another. I stopped shooting them for awhile because I was to scared to use them.,Who the bullet makers are is not important. I still shoot they're bullets!) So I wanted to see what would happen. Bought some more of those one makers bullets and guess what. No failures in either one. So in away that kinda blows the theory!?
Both barrels we're made to the same bore and groove size and same twist. Same chamber and the same loads shot thru them. Why didn't the one barrel blow up anymore of the one makers bullets anymore? I chalk it up to a different lot. Maybe the lot of bullets I got had problems with the cores or jackets? Hard to say!
Barrel life? Again I don't see a difference in the number of grooves effecting barrel life etc...One barrel maker who is making 3 groove barrels the last I heard was claiming they last longer. This might be true in a button rifled barrel because of the wider lands. On average I don't see a button rifled barrel lasting as long as a cut rifled barrel. Why?
Because the button rifling operation work hardens the bore. I'm not saying a button barrel will not go a long time or a cut barrel will not burn out early as I've seen both. It's just what we see as an average. Can I put a number on it. Not really but if I had to I would say about 20% longer on cut barrels but this all depends on the accuracy level each individual shooter wants/needs, how good they are not to mention a whole ton of other variables that effect barrel life. One guy shoots a powder that is more abrasive than another is an example. Not to mention the steel from one lot to another even if you are getting the steel from the same supplier can be a variable. The list doesn't stop almost.
When we we're at Krieger back around 2000 Tracy made the tooling for a 3 groove .30cal. palma barrels and we made a couple for Mid Tompkins. Mid told me that accuracy wise out to 800 yards they shot just fine compared to the 4 grooves. The only problem was both barrels we're a flat 100-150fps. slower than the 4 grooves so they wouldn't cut it at 900 and a 1000 yards. due to the velocity loss. Why? Maybe because of the wider lands? Different lot of steel? Hard to say sometimes but that is my guess the wider lands.
Also at Krieger right before we we're gone from they're we made a cut rifled barrel and a button rifled barrel in .224 cal. for John. He chambered them up in .22-250 and put them on some prairie dog guns that he took out west. They we're made out of the same lot of steel and got the same loads thru them. Accruacy wise both shot great but the button barrel was exhibiting more wear with the same round count on both. Both barrels we're being shot in the same conditions and the same loads we're being put thru them.
I've seen 2 groove, 3's, 4's, 5's,5R's) and 6 groove barrels all shoot excellent. So again I say there is no difference in in accuracy or barrel life but when you compare one or the other you should be comparing/testing the barrels made out of the same lot of steel and being made from the same maker and being shot in the same conditions. This is the only way to get good results but who has the time, money etc...to do this? This is the hard part.
Check out the thread records fall at Sacramento. Craig St.Clair shot a 1-8 twist, 4 groove, .237 bore at 600 yards chambered in 6BR. He won 7 out of 8 awards and has 2 pending records. It was smithed by Stu Harvey.
In the end to me it is more of the quality of the barrel blank. The straighter the barrel, the more uniform the bore and groove dimensions, and the more uniform the twist the more forgiving the barrel is going to be. The nicer the finish inside the less fouling it will have etc....
Keep in mind there are alot of variables beyond the barrel maker and gunsmiths control and even the shooters control. What chamber reamer was used. Different lot of bullets from one to the next, different lot of powders, primers, cases etc...all effect different things. Why is one barrel faster than one vs. another. Why does one barrel that looks glassy smooth foul bad and it shouldn't etc................
Talk to you all later, Frank @ Bartlein Barrels
butchlambert
Site $$ Sponsor
Frank, Ed Shilen mirrored what you have said about the lands and grooves. Their ratchet barrel is similar to the 5R I believe.
Didn't those bullets only blow up on cutrifled barrels?
Butch
Didn't those bullets only blow up on cutrifled barrels?
Butch
butchlambert said:
Butch, bullets can blow up in a cut or a button barrel. I think it has more to do with thin jackets and twist than any other reason. I chambered a PacNor 7 twist,think it is a 3 groove)for a buddy in 6mmAI that 115 Bergers just wont hold up in. Its the J4's and the 7 twist that are the culprit I'm sure. If you check with Berger, they will say that a 7 is needed to stabilize the 115gr bullets. Even when these bullets were slowed down to 2850, the rifle would still blow them up periodically.
Butch, Not all of the barrels have been blowing up bullets have been cut rifled. I know of some 6.5's that have been blowing up bullets and they are button rifled just in the last few months.
Some people have said it's because the barrels have tight bores vs. standard bores. Those two 6mm's I listed in the earlier post we're both tight bore,.236 vs. .237) 6mm's. But I agree that a tight bore barrel might not be helping anything but in my case both we're tight and why did one lot of bullets fail and the next lot didn't? I was getting 1-2 out of every 20 that would fail!
I suggest this. If a guy wants conventional style rifling I try and steer them towards a standard bore size. The tight bore isn't going to shoot anymore accurately or last longer. If they insists on going tight and doesn't have a preference for the number of grooves than I try and steer him towards the 5R. I'm just trying to help so a guy doesn't have jacket failures.
I have customers who insist on using the tight bore 6's in a 4 groove and have never had a bullet failure problem. So go figure.
What do I think causes it? Hell I don't exactly know. I here so many different things it's unbelievable.
When I tested both guns side by side at the time my thought was this. Maybe it's a combination of things! One was velocity. My loads in the one gun average 3180fps. So I was thinking it was velocity, thin bullet jacket and the tight bore just wasn't a good combination and we're all working against one another. But then after shooting a couple of match's with them and getting two new lots of bullets to try from the one maker and shooting them up until they we're all gone,one supplied and one I bought myself) I didn't have a single failure! Go figure! In the one barrel that did blow them up at one time, I even shot it again early this last summer in a 4 man team match in the long range regionals. We won our class and came in 3rd overall. No failures!
When the last barrel started blowing up bullets on me it had less than 40 rounds on it. So the throat was nice and not all chewed up like the throat was burned out or anything. The barrel before it I pulled off because it had a lot of rounds on it and the throat was getting rough. So that's what I chalked it up to,but the old barrel still wouldn't blow up another makers bullets). So put a new stick on. To my horror in the next match I shot it and my 18th round for record the bullet never made it to the target! I ended up with a 187 - 12x's with a scored miss at a 1000yds! Talk about bummed out!
Another thing I've been hearing is that bullets,again I'm not saying or listing manuf. because it doesn't matter at this point because I cannot prove anything either way)in barrels longer than 28" the failure rate goes up. This is supposedly due to the bullet being in the bore for a fraction of second longer and are still generating heat which is stressing the jacket/core. I can't prove this but what I hear.
Talk to you all later,Frank
Some people have said it's because the barrels have tight bores vs. standard bores. Those two 6mm's I listed in the earlier post we're both tight bore,.236 vs. .237) 6mm's. But I agree that a tight bore barrel might not be helping anything but in my case both we're tight and why did one lot of bullets fail and the next lot didn't? I was getting 1-2 out of every 20 that would fail!
I suggest this. If a guy wants conventional style rifling I try and steer them towards a standard bore size. The tight bore isn't going to shoot anymore accurately or last longer. If they insists on going tight and doesn't have a preference for the number of grooves than I try and steer him towards the 5R. I'm just trying to help so a guy doesn't have jacket failures.
I have customers who insist on using the tight bore 6's in a 4 groove and have never had a bullet failure problem. So go figure.
What do I think causes it? Hell I don't exactly know. I here so many different things it's unbelievable.
When I tested both guns side by side at the time my thought was this. Maybe it's a combination of things! One was velocity. My loads in the one gun average 3180fps. So I was thinking it was velocity, thin bullet jacket and the tight bore just wasn't a good combination and we're all working against one another. But then after shooting a couple of match's with them and getting two new lots of bullets to try from the one maker and shooting them up until they we're all gone,one supplied and one I bought myself) I didn't have a single failure! Go figure! In the one barrel that did blow them up at one time, I even shot it again early this last summer in a 4 man team match in the long range regionals. We won our class and came in 3rd overall. No failures!
When the last barrel started blowing up bullets on me it had less than 40 rounds on it. So the throat was nice and not all chewed up like the throat was burned out or anything. The barrel before it I pulled off because it had a lot of rounds on it and the throat was getting rough. So that's what I chalked it up to,but the old barrel still wouldn't blow up another makers bullets). So put a new stick on. To my horror in the next match I shot it and my 18th round for record the bullet never made it to the target! I ended up with a 187 - 12x's with a scored miss at a 1000yds! Talk about bummed out!
Another thing I've been hearing is that bullets,again I'm not saying or listing manuf. because it doesn't matter at this point because I cannot prove anything either way)in barrels longer than 28" the failure rate goes up. This is supposedly due to the bullet being in the bore for a fraction of second longer and are still generating heat which is stressing the jacket/core. I can't prove this but what I hear.
Talk to you all later,Frank
butchlambert
Site $$ Sponsor
It is remarkable that some people swear that a .236 is the only thing that will shoot and the other half say they would only use a .237. I can't document that either has an advantage. Basically you are only looking at .0005 difference in land height between the two. Maybe some of those fat 6mm bullets that I use to have with a .2438 pressure ring might not like the tight bore.
A barrelmaker can buy the best steel that he can find, drill and ream the straightest hole possible. He can then rifle it the best he is capable. The barrel maker has to deal with a smith that may or may not do a good job, then he has to deal with a shooter that may or may not be a capable shooter. The barrel is the first thing we blame when we have a problem.
Case in point. I had a barrel on a Panda a few years ago that didn't shoot to my satisfaction. I gave it to Al Flores and he proceeded to shoot 2 .090s during 1 aggregete at the Buffalo Shoot in Midland. Go figure.
Thanks for your contribution Frank. You've been around the block and heard all the stories.
Butch
A barrelmaker can buy the best steel that he can find, drill and ream the straightest hole possible. He can then rifle it the best he is capable. The barrel maker has to deal with a smith that may or may not do a good job, then he has to deal with a shooter that may or may not be a capable shooter. The barrel is the first thing we blame when we have a problem.
Case in point. I had a barrel on a Panda a few years ago that didn't shoot to my satisfaction. I gave it to Al Flores and he proceeded to shoot 2 .090s during 1 aggregete at the Buffalo Shoot in Midland. Go figure.
Thanks for your contribution Frank. You've been around the block and heard all the stories.
Butch
Butch, Well said in your last post!
Good shooting to all! Frank
Good shooting to all! Frank
Well when Berger came out with a 55gr 20 caliber bullet I screwed on a 8 twist in which what was recommended an got one bullet on target an the rest blew up about 20 yards away at 3700 fps they didn't work screwed a 9 twist on problem solved.
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