PDA

View Full Version : Hard & Fast Barrel Rules



GPat
03-05-2014, 11:15 AM
Alright, I have more barrels sitting around here than I've had at one time my whole life. I've got two buttoned barrels and four cut barrels. I know to some guys this is nothing, but to me it's a glut of barrels.

It's been a while since I've had a button barrel and the last one I shot was before boat tails were as popular as they are today. Does ye olde hard and fast rule about flat base bullets in button barrels and boat tails in cut barrels still hold today? Or is this just a rule of thumb?

Pat

James M.
03-05-2014, 11:52 AM
In my opinion, good bullets of either type will shoot well in either cut or buttoned barrels. There has been a move to BT bullets in the last few years, but it may be a case of "monkey see, monkey do". I have a Bartlein (cut) barrel that prefers Bart's Ultra FB bullets, while a Krieger that I have loves the BT's from either Bart or Hottenstein. I have not tried BT bullets in my Hart barrels, but perhaps I need to. Does this small sample prove anything.....probably not. Good shooting, James

mwezell
03-05-2014, 11:56 AM
Alright, I have more barrels sitting around here than I've had at one time my whole life. I've got two buttoned barrels and four cut barrels. I know to some guys this is nothing, but to me it's a glut of barrels.

It's been a while since I've had a button barrel and the last one I shot was before boat tails were as popular as they are today. Does ye olde hard and fast rule about flat base bullets in button barrels and boat tails in cut barrels still hold today? Or is this just a rule of thumb?

Pat

I really doubt the bullet knows how the rifling was put in the barrel. Some may feel one is better than the other, but I don't think they can prove it. A good barrel is a good barrel, but they might not like all bullets...regardless of bt vs. fb. JMHO

skeetlee
03-05-2014, 09:25 PM
I hate bt bullets! LOL!!! FB bullets rule!!!! lee

Lee Martin
03-05-2014, 10:01 PM
I've used both button and cut as well as FB's and BT's in our 6 Norma BR. I'm no expert, but I can't tell much of a difference. As mentioned, there are too many variables to consider even if I tied to pin a preference on the gun.

-Lee
www.singleactions.com

GPat
03-06-2014, 09:32 AM
Thanks for the replies.

I've got plenty of both style bullets. I had planned on trying everything, but I want to start with the button barrel and flat bases. I have enough of them to burn out a barrel or two.

Pat

Andy Cross
03-07-2014, 06:03 PM
I really doubt the bullet knows how the rifling was put in the barrel. Some may feel one is better than the other, but I don't think they can prove it. A good barrel is a good barrel, but they might not like all bullets...regardless of bt vs. fb. JMHO

Barrels are a fickle thing. Slight variations in the steel composition, surface tensions, internal stresses will all play a part in how the barrel vibrates under fire which relates to its harmonics. Addressing the secondary harmonic and getting it to counter heterodyne as closely as possible with the primary would go a long way into turning it into a hummer no matter what quality bullet you fed it. Problem - testing for the secondary harmonic alters the result. So you would have to interpret what it looked like before you looked at it. Then from that establish cause and effect on what alterations to do to make it shoot better.
Andy.

mwezell
03-08-2014, 07:46 AM
Barrels are a fickle thing. Slight variations in the steel composition, surface tensions, internal stresses will all play a part in how the barrel vibrates under fire which relates to its harmonics. Addressing the secondary harmonic and getting it to counter heterodyne as closely as possible with the primary would go a long way into turning it into a hummer no matter what quality bullet you fed it. Problem - testing for the secondary harmonic alters the result. So you would have to interpret what it looked like before you looked at it. Then from that establish cause and effect on what alterations to do to make it shoot better.
Andy.

Easy...just move the tuner a little.:p

Andy Cross
03-08-2014, 07:18 PM
Easy...just move the tuner a little.:p

Not the same thing. Attaching a tuner modifies the primary harmonic and generates its own secondary being generated at the point of attachment.. Back to square one. If attaching a tuner was able to turn any barrel into a hummer you wouldn't see a BR rifle on the line that didn't have one.
Andy.

Greyfox
03-08-2014, 08:38 PM
Not the same thing. Attaching a tuner modifies the primary harmonic and generates its own secondary being generated at the point of attachment.. Back to square one. If attaching a tuner was able to turn any barrel into a hummer you wouldn't see a BR rifle on the line that didn't have one.
Andy.

Just curious....do you use a tuner?

Rick

mwezell
03-08-2014, 09:59 PM
Not the same thing. Attaching a tuner modifies the primary harmonic and generates its own secondary being generated at the point of attachment.. Back to square one. If attaching a tuner was able to turn any barrel into a hummer you wouldn't see a BR rifle on the line that didn't have one.
Andy.
Andy, by all means, please continue. I'll read and do my best to understand while you explain your take on this subject, as it interests me a good bit. At the same time, I'll be shooting, trying to deal with the things that are within my control. Do you use a tuner? If so, I'd like to hear your take on them..in use. If not, why not?....Thanks

Andy Cross
03-08-2014, 11:23 PM
Andy, by all means, please continue. I'll read and do my best to understand while you explain your take on this subject, as it interests me a good bit. At the same time, I'll be shooting, trying to deal with the things that are within my control. Do you use a tuner? If so, I'd like to hear your take on them..in use. If not, why not?....Thanks




Andy, by all means, please continue. I'll read and do my best to understand while you explain your take on this subject, as it interests me a good bit. At the same time, I'll be shooting, trying to deal with the things that are within my control. Do you use a tuner? If so, I'd like to hear your take on them..in use. If not, why not?....Thanks

I used to use a tuner. I tried two barrels with one and two without. The net result after shooting all 4 barrels out was that one barrel with a tuner out agged one barrel without and one without a tuner out agged the other one with a tuner. How big were the differences about 42 thou. In other words not much. Consequently I don't bother with tuners any more.

Attaching tuners is just that attached. They are not a part of the barrel. This essentially adds a sub system to a system that already has many components in it. And thus with that its own set of variables. With each set of variables a event in physics known as moment occurs. Moment can be said to be the product of a force multiplied by the distance between the force and its point of application. When a moment occurs a primary and secondary harmonic will result. I'd sooner just adjust the load parameters to suit the conditions.
Andy

alinwa
03-09-2014, 12:24 AM
I used to use a tuner. I tried two barrels with one and two without. The net result after shooting all 4 barrels out was that one barrel with a tuner out agged one barrel without and one without a tuner out agged the other one with a tuner. How big were the differences about 42 thou. In other words not much. Consequently I don't bother with tuners any more.

Attaching tuners is just that attached. They are not a part of the barrel. This essentially adds a sub system to a system that already has many components in it. And thus with that its own set of variables. With each set of variables a event in physics known as moment occurs. Moment can be said to be the product of a force multiplied by the distance between the force and its point of application. When a moment occurs a primary and secondary harmonic will result. I'd sooner just adjust the load parameters to suit the conditions.
Andy

This is a complete and comprehensive answer, pithy.

al

mwezell
03-09-2014, 10:35 AM
I used to use a tuner. I tried two barrels with one and two without. The net result after shooting all 4 barrels out was that one barrel with a tuner out agged one barrel without and one without a tuner out agged the other one with a tuner. How big were the differences about 42 thou. In other words not much. Consequently I don't bother with tuners any more.

Attaching tuners is just that attached. They are not a part of the barrel. This essentially adds a sub system to a system that already has many components in it. And thus with that its own set of variables. With each set of variables a event in physics known as moment occurs. Moment can be said to be the product of a force multiplied by the distance between the force and its point of application. When a moment occurs a primary and secondary harmonic will result. I'd sooner just adjust the load parameters to suit the conditions.
Andy

This brings up a couple more questions. First, when using a tuner, did you use the tuner itself, change load, or both to maintain tune?
Also, it would seem that the force generated would have to be greater than that of the attachment, to "unload", if you will, creating the second "moment". Second, as I understand it, harmonics travel at the speed of sound. Is it possible for this second moment to occur when the bullet is traveling at roughly three times that speed, and the bullet still be in the barrel when it does?

My experience with tuners has not been that they will improve accuracy potential, but that the tune window becomes wider, which will yield better aggs...unless you are capable of equal or better tuning by traditional methods. Myself, and most of us are not capable of adjusting powder charge/etc.,for tune at that high level, consistently. I admire those of you that can and feel that this is a big factor in what separates the best shooters from the rest of us. Tuners keep me from missing the tune badly, and shooting BIG, and can be adjusted at the bench. That's why I use a tuner. As I read it, you are very proficient in keeping your rifle in tune by traditional methods, or possibly not using a tuner to it's full potential. That's the reason for my first question. All in all, if a shooter never misses the tune, they don't need a tuner, but for those of us that do, the ability to find that tune, at the bench, is worth it, IMHO, particularly if the variable of the attachment creating a second moment is so small that you really found no great difference with or without one. That seems to nullify worrying about the second moment...if it happens while the bullet is still in the barrel. That's the reason for my second question.

Thanks for your time answering, Andy. This is good information that may help with tuner design and attachment, or even not using them at all.--Mike

Andy Cross
03-09-2014, 06:44 PM
I usually adjusted the load for the conditions then fine tuned it with the tuner. Trying to find the sweet spot with the tuner alone was more problematic for me than using a load I know worked in the conditions. Of cause none of this was worth a damn when you had a barrel that wasn't going to shoot any way.

Both the primary and secondary harmonic would travel at the speed of sound in air but in media like water or steel where the molecules are a lot closer together they travel a lot faster. The first shock wave occurs when the firing pin reaches the end of its travel before the priming mixture detonates. The cross hairs will still do that little wiggle you see that happens when you dry fire it. That's why I get the thing to return to battery when its being dry fired before I start a group. Get it settled on the rest and bags.

The secondary harmonic that is generated would be travelling back along the barrel while the bullet is still in it. Imagine playing one of those steel guitars they use in country music. Place the block in the middle and pluck a string on the right side of the block. Move the block to the right essentially shortening the dtring. The primary harmonic changes. Is the string vibrating on the opposite side of the block. You bet ya. Secondary harmonic which goes through the amp along with the primary. Now play the same note by plucking the string on the left side of the block and move the block to the left. You won't get the same note. Different secondary harmonic. That's because the string is anchored at one end and simply tightened the other. A barrel is like a string but only anchored at one end. The bullet is the sliding block. A heavier barrel does not alter the frequency of the burn. Just the amplitude of the primary and secondary harmonic. Thus a heavy barrel is essentially harder to tune but has the potential to shoot smaller groups when the nodes are found. It's really just the laws of physics. When you take into account all the intervening variables it is a miracle we can shoot groups as small as we do.
Andy

blades
03-12-2014, 04:24 PM
Very nice Andy, within your last couple posts you have dissipated a whole lot of smoke and stripped the silver-nitrate off the back side of the looking glass.

Andy Cross
03-13-2014, 05:10 AM
Very nice Andy, within your last couple posts you have dissipated a whole lot of smoke and stripped the silver-nitrate off the back side of the looking glass.

The way I interpret the myths revolving around the hummer barrel are this. Most BR quality barrels have hummer potential. It's a matter of getting all the variables going terribly right. The harmonics both primary and secondary, bullet batch concentricity etc all working together. But getting closer to a hummer would mean getting that final tweak of barrel profile, length and addressing both harmonics before anything else. It would take an exhaustive amount of R&D for a barrel maker to achieve those results and then pass on to the riflesmiths what to do and how to do it to achieve the same results. I can't see that happening even if the science to achieve it exists.
Andy.

mwezell
03-13-2014, 07:07 AM
The way I interpret the myths revolving around the hummer barrel are this. Most BR quality barrels have hummer potential. It's a matter of getting all the variables going terribly right. The harmonics both primary and secondary, bullet batch concentricity etc all working together. But getting closer to a hummer would mean getting that final tweak of barrel profile, length and addressing both harmonics before anything else. It would take an exhaustive amount of R&D for a barrel maker to achieve those results and then pass on to the riflesmiths what to do and how to do it to achieve the same results. I can't see that happening even if the science to achieve it exists.
Andy.

I agree, Andy. One of the best barrels I've had was one that I bought used and set back. The previous owner said it wouldn't shoot. I didn't do anything magical to it, but it came ALIVE and lasted longer than it should, too.

Frank Green
03-13-2014, 02:33 PM
Alright, I have more barrels sitting around here than I've had at one time my whole life. I've got two buttoned barrels and four cut barrels. I know to some guys this is nothing, but to me it's a glut of barrels.

It's been a while since I've had a button barrel and the last one I shot was before boat tails were as popular as they are today. Does ye olde hard and fast rule about flat base bullets in button barrels and boat tails in cut barrels still hold today? Or is this just a rule of thumb?

Pat

Total BS, flat out myth!

The straighter the barrel blank, the more uniform the twist and the more uniform the bore and groove sizes over the whole length of the barrel the more forgiving the barrel is going to be!

Later, Frank
Bartlein Barrels

Frank Green
03-13-2014, 02:39 PM
I agree, Andy. One of the best barrels I've had was one that I bought used and set back. The previous owner said it wouldn't shoot. I didn't do anything magical to it, but it came ALIVE and lasted longer than it should, too.

Seen a lot of stupid stuff in the years and a lot has been blamed on barrels regardless of the maker! Some of the things that we've seen and continue to see......

Damage to muzzle crowns. Weather from cleaning or from when the barrel was initially installed! Just repaired a .30-06 tactical rifle. The gunsmith who installed it damaged the last 1/2" of rifling. The customer had some bullets going thru the target sideways at a 100 yards. He sent the rifle to us for us to look at. That's what we found. We cut off the 1/2" of the barrel. Rethreaded the muzzle and recrowned it. The rifle is now shooting 1/3moa or less with box ammo.

Not enough bolt clearance to the breech face of the barrel. Last barrel we had went from shooting mid .2xx's to now shooting mid .1xx's.

Barrels not tight enough on the actions!

Damage from cleaning!

Bullets vary from lot to lot!

The list can go on!

Later, Frank
Bartlein Barrels

mwezell
03-13-2014, 03:48 PM
Seen a lot of stupid stuff in the years and a lot has been blamed on barrels regardless of the maker! Some of the things that we've seen and continue to see......

Damage to muzzle crowns. Weather from cleaning or from when the barrel was initially installed! Just repaired a .30-06 tactical rifle. The gunsmith who installed it damaged the last 1/2" of rifling. The customer had some bullets going thru the target sideways at a 100 yards. He sent the rifle to us for us to look at. That's what we found. We cut off the 1/2" of the barrel. Rethreaded the muzzle and recrowned it. The rifle is not shooting 1/3moa or less with box ammo.

Not enough bolt clearance to the breech face of the barrel. Last barrel we had went from shooting mid .2xx's to now shooting mid .1xx's.

Barrels not tight enough on the actions!

Damage from cleaning!

Bullets vary from lot to lot!

The list can go on!

Later, Frank
Bartlein Barrels

I agree, Frank. Lots of reasons why a gun will or won't shoot...not just good or bad barrels. We know you guys do a great job. Keep it up !

GPat
03-13-2014, 06:11 PM
Thanks Frank, The last barrels I had from you guys shot flat base bullets best, but I really kept thinking it was because the boattail bullets I had were suspect. Now I have a quality supply of both types of bullets and plenty of barrels to work with.

skeetlee
03-14-2014, 09:42 PM
frank
why would someone send a barrel back in that was shooting .2xx's? seems a bit selfish, lol!!! Thanks for sharing. Lee