adk hunter
Well-Known Member
At least we haven't heard from a Colonel...lol
My barrel needs to go on a Diet!
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At least we haven't heard from a Colonel...lol
25WSM
Well-Known Member
Well I have a fancy piece of paper that says I'm a master gunsmith. So now I declare the new. Master25wsm.
I say just flute the darn thing Already.
Shep
I say just flute the darn thing Already.
Shep
Sam Summey
Well-Known Member
Anything you do to the outside will affect the harmonics of the barrel. Of the things you do that will have the least affect is fluting, however removing the barrel from the action and reinstalling it will have an affect too.
25WSM
Well-Known Member
Well I install and replace barrels on my match rifles all the time. I use 4 on my 17 pound light gun and I can tell you that nothing changes between them. The tune stays the same. After 3 foul shots the impact point is back to the same. And every short range bench rest competitor will tell you the same. And these are all done on small barrel vices at the range. Nothing fancy. You are correct that any weight taken off the barrel will change the harmonics. Cutting just the threads for a brake will affect your tune. Adding the brake on will change it again. Take it off and put a thread protector on it will change your tune. But once you retune all will be back to normal again.
Shep
Shep
HaroldNRAEndowment
Well-Known Member
I have not specialized in machining or building rifles, and I have been a Mechanical Designer over a span on 35 years and an NRA Member since 1978. To help with the terminology with cutting rifling versus using a button, I will use as many synonyms as possible and may not indicate a complete process but relative to stress. All steel has internal stress just sitting on the table not being used and I will get into that at the end. Cutting the rifling involves pulling a metal cutter in a spiraling motion through the barrel to create the rifling. Through articles read generally it cuts one groove at a time and then the start point is indexed to start cutting the next rifled groove until all the grooves are cut. The metal cutter is hardened steel and has a sharp edge that cuts/shaves the metal away from it's current position and does not push the metal to another position or deform the metal, it is just removing the metal. The button type rifling Uses a shape like a button and the cross sectional profile is the same as the rifling similar to a spline, but the leading edge as it is pulled through the barrel does not cut. It starts with a taper/chamfer with a smaller than final diameter(lead in) and gradually increased in size to the final rifling size. A Button is elongated similar to a bullet but is hardened and usually made of carbide and of has the rifling shape on the surface. The old world term is the button irons the rifling into the steel. I do not exactly like that term but it is pressing the rifling form into the steel as the button is pulled down the pilot bore in a spiraling motion. In order to press the rifling into the steel, that is displacing/moving the steel somewhere else which is essentially deforming the barrel radially. That is a lot of stress. I have read an article to where the end of the barrel's outside diameter was made too small, exit end, to where the great amount of force actually allowed the outside diameter to increase and caused the end of the bore to essentially go cone shaped(oversized bore) and resulted in horrible accuracy. In other words the bullet would lose a good solid contact with the barrel and start bouncing around upon exiting. So why does that not happen all the way down. When the thickness of the barrel's wall is strong enough due to proper sizing of the outside diameter, during button rifling, the steel is strong enough to resist deformation, even after the rifling has been pressed into the steel. The result is the rifling stress in the steel is there but the strength of the outer part of a properly sized barrel is higher than the deformation stress of the rifling so the barrels outside diameter does not change, thus holding the rifled bore to the intended dimension of the shape of the button. That strength is somewhat stable in the short term but over a span of time the barrel will start to stress relieve. A symptom is one can sight in the rifle and the point of impact is were it is expected plus accuracy. Then after the rifle has been sitting for a while then when one decides to pick up the rifle and shoot again, some length of time later, the point of impact has changed and then it can be very frustrating knowing it was shooting as expected the last time the rifle was stored. Another article pertaining to shooters that run high volumes of ammunition(target shooters) say one has to adjust the sights on a regular basis from session to shooting session(we are not talking about due to heating up during a shooting session). 1) Steel always has stress resident in it. 2) The existing stresses promotes stress relieving just sitting on a shelf. 3) Stress relieving is accelerated with each heat and/or vibration(impacts) thus the more the firearm is shot the more often the sights need to be adjusted. And finally talking about metallurgy. Each type steel's molecules have a geometric pattern and when the specific type of steel molecules connects to another molecule of the same, there are specific connection points that make a crystal. Yes even steels structure uses the term crystals as in gems, but refers to it's normal geometric shape and the natural connection points to make the crystal of steel also know and cells. Ideally it would be great if steel would form into one steel cell(crystal) as it solidified from molten to solid. What actually happens is think of a vat of steel that you pull out of the oven in a container and let it start cooling. It will not start cooling molecule by molecule from 1 point outwards. What happens is the steel will start solidifying at billions of points separated. Then a cell(crystal) will start growing, but as this happens there is also a cell growing next to it. With 1 cell it could be said you have a perfect crystal with all the molecules connecting at the perfect connection points. As it grows, what happens is the cell next to it is also growing, But the position is such that the perfect connection points are misaligned and at the same time there is a forced connection going from molten to solid. Now what happen, the molecules, in one cell(crystal) are pushing against the adjacent cell(crystal) for the perfectly relaxed position. It is like a jagged boundary. Between cells there will be a lot of connections that are correct and there will be a lot of molecules that cannot reach the other molecule connection points. All this stress is at the pressures that exemplifies how strong steel is. Over time the imperfect connection points can be dislodged by a point on one molecule trying to find a connection and would be a more perfect connection point. Heat weakens connection point and impacts jar connection points, through shear force can dislodge a imperfect connection point to where it moves out the way for an ideal connection point that was never connected. All this happens by the force of the orbits of electrons trying to pull them selves to the stronger perfect connection, not a lot different action than a magnet pulling itself to steel. This information is the basics. Maybe a qualified metallurgist will have more correct terms and more insight. The overall picture is metal changes shape due to stress relieving as in warping, and the harmonic frequency as in matching loads to barrel can change. Best Regards.
Possum Cop
Well-Known Member
Proof research makes light stiff barrels to use with the switch lug for around $900.
I have a switch lug on a MPA rifle and have been very happy with it and the ability to change barrels as needed.
Just my 2 cents.
Best of luck with your decision.
I have a switch lug on a MPA rifle and have been very happy with it and the ability to change barrels as needed.
Just my 2 cents.
Best of luck with your decision.
BigJohnH
Well-Known Member
First off I will say this I have a 17lb .308 Savage action, it has a 28" Heavy SSS barrel and a Choate Ultimate Sniper stock and I carry it in the woods hunting. I am 60 yrs old and have no issues with the weight. The issue may not be with the weapon. Having said that I would do nothing to the weapon as it seems according to you it shoot fines to quote and old adage " it ain't broke don't fix it.
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25WSM
Well-Known Member
Hey guys hold this thread. I'm going to go get a college degree so I can actually read that post here. I'll be back in 4 yrs.were mere mortals
Harold take it easy on us man. I just wish my barrel guys were on here to make it easy for us to understand. I'm not even sure what the questions are now. As far as fluting barrels go this has been on here before. Some manufacturers say they will flute their own barrel for you. So right off a barrel company says they will do it. I'm sure some say no. I texted my barrel guy and I will let you know what he says. Actually just heard back. He said fluting will not hurt a barrel..
Shep
Harold take it easy on us man. I just wish my barrel guys were on here to make it easy for us to understand. I'm not even sure what the questions are now. As far as fluting barrels go this has been on here before. Some manufacturers say they will flute their own barrel for you. So right off a barrel company says they will do it. I'm sure some say no. I texted my barrel guy and I will let you know what he says. Actually just heard back. He said fluting will not hurt a barrel..
Shep
HaroldNRAEndowment
Well-Known Member
The reason I went down this path was it seems no one answered a question as what is the difference between cutting rifling and using a Button rifling method relating to stress. Just trying to help.
HaroldNRAEndowment
Well-Known Member
Due to post #23 on page 2. Best Regards
You properly stress relieve a button barrel and there is no difference.
Key word is properly not all stress relieving is the same.
PredatorSlayer
Well-Known Member
bigngreen
Well-Known Member
I think that's the key, the reputation of button being worse has come from ghetto in house, Billy Bob heat treating or not paying attention to the steel chemistry lot to lot and just throwing on the same process and putting out some poor steel. I've had both button and cut move on fluting, to the point a proven barrel was scraped.
25WSM
Well-Known Member
Ok guys I'm going to put up what my guy said to me in my text. His shop is one of the top manufacturers of match grade barrels but ask me to not drag his name in the forum battles.
Shep
Shep
