What barrel profile has the best accuracy potential.

[Alex Wheeler]

Heres some good reading if you havent seen it yet.
http://www.varmintal.com/atune.htm

 

[seymour fish]

Is it safe to say that short-range barrels (short fat relatively Stiff) with higher vibratory frequency are optimal as 1) there is no need for positive compensation a la Varmint Al at point-blank range 2) With nodes so close together, they shoot well dumping powder, inaccurately by long-range standards, without seeming to be slaves to ES/SD, just running at a speed range where the system is known to be happy given atmospherics ? Perhaps it follows that longrange barrels though fat, are of necessity long, thus less stiff relatively, and operate at sufficiently low frequency to allow tuning into those wide nodes that Mike mentions, to benefit from positive compensation ? Seems a fair synopsis of expert opinion. Seymour

 

[jlow]

Heres some good reading if you havent seen it yet.
http://www.varmintal.com/atune.htm

I’ve looked through that write up before and honestly most of it is over my head even though I have an advanced science degree. :

Part of the problem here is the authors makes a lot of assumptions in terms of knowledge of the reader and so does not explain carefully what he is talking about even early on. In my own experience doing this type of technical article, this is a bit deadly as if you loose your audience early, you loose them period. The author I am sure knows his stuff but you only have to go to the third paragraph to run into things like “FEA” results – what is that?

The second problem is the article is about tuners and not comparing different barrel profiles or even thickness for that matter.
Still, there are some gems in there. For example, he clearly says “The additional mass reduce the amplitude of the vibrations” this would be consistent with less amplitude with a heavier barrel?

 

[Alex Wheeler]

Is it safe to say that short-range barrels (short fat relatively Stiff) with higher vibratory frequency are optimal as 1) there is no need for positive compensation a la Varmint Al at point-blank range 2) With nodes so close together, they shoot well dumping powder, inaccurately by long-range standards, without seeming to be slaves to ES/SD, just running at a speed range where the system is known to be happy given atmospherics ? Perhaps it follows that longrange barrels though fat, are of necessity long, thus less stiff relatively, and operate at sufficiently low frequency to allow tuning into those wide nodes that Mike mentions, to benefit from positive compensation ? Seems a fair synopsis of expert opinion. Seymour

Yes, stiffness of a barrel/rifle is directly related to positive compensation. Stiff works at short range, at long range you need some flex to get that possitive compensation. stiff, low profile rifles seem popular, but they are not ideal in long range.

Jlow, yes that correct.

 

[dkhunt14]

Is it safe to say that short-range barrels (short fat relatively Stiff) with higher vibratory frequency are optimal as 1) there is no need for positive compensation a la Varmint Al at point-blank range 2) With nodes so close together, they shoot well dumping powder, inaccurately by long-range standards, without seeming to be slaves to ES/SD, just running at a speed range where the system is known to be happy given atmospherics ? Perhaps it follows that longrange barrels though fat, are of necessity long, thus less stiff relatively, and operate at sufficiently low frequency to allow tuning into those wide nodes that Mike mentions, to benefit from positive compensation ? Seems a fair synopsis of expert opinion. Seymour

Yes, stiffness of a barrel/rifle is directly related to positive compensation. Stiff works at short range, at long range you need some flex to get that possitive compensation. stiff, low profile rifles seem popular, but they are not ideal in long range.

Jlow, yes that correct

What are you meaning by a stiff barrel? A 1.250 straight or a 1.450 straight. Some of the best knots and groups I ever saw were shot with 1.450 straight barrels at 30 inches glued into 9 inch blocks. I would think that is about as stiff as it gets. Unless you are Eddie and use 2 inch barrels. These barrels including Eddies have shot extremely small. Maybe they are harder to tune but I seen them shoot really small and consistently do it. Matt

 

[Alex Wheeler]

Is it safe to say that short-range barrels (short fat relatively Stiff) with higher vibratory frequency are optimal as 1) there is no need for positive compensation a la Varmint Al at point-blank range 2) With nodes so close together, they shoot well dumping powder, inaccurately by long-range standards, without seeming to be slaves to ES/SD, just running at a speed range where the system is known to be happy given atmospherics ? Perhaps it follows that longrange barrels though fat, are of necessity long, thus less stiff relatively, and operate at sufficiently low frequency to allow tuning into those wide nodes that Mike mentions, to benefit from positive compensation ? Seems a fair synopsis of expert opinion. Seymour

Yes, stiffness of a barrel/rifle is directly related to positive compensation. Stiff works at short range, at long range you need some flex to get that possitive compensation. stiff, low profile rifles seem popular, but they are not ideal in long range.

Jlow, yes that correct

What are you meaning by a stiff barrel? A 1.250 straight or a 1.450 straight. Some of the best knots and groups I ever saw were shot with 1.450 straight barrels at 30 inches glued into 9 inch blocks. I would think that is about as stiff as it gets. Unless you are Eddie and use 2 inch barrels. These barrels including Eddies have shot extremely small. Maybe they are harder to tune but I seen them shoot really small and consistently do it. Matt

Matt, its relative. The stiffer the setup the narrower the nodes and harder to tune because the dont compensate so they depend on ES. At some point the gun would become un tunable if it was stiff enough. In the short range the trend has been moving to stiffer. But a hall of fame shooter I know says the guns are harder to keep in tune than they used to be. He believes they have gotten a little too stiff. I built a fiberglass stock and glued a panda in it for Tom. It was kind of a test, this stock has a high bore line, low center of gravity, and is like a noodle. It is shooting very well for him. I dont know if he feels like it tuned easier or has a wider node. Maybe he'll comment.

 

[jim_k]

I would bet I have had chambered over 100 barrels in various calibers from .223 all the way to a .358 S.T.A. In all those barrels I have had 2 for sure and maybe 3, that would be considered R-E-A-L "hummers". One was a .257 Roberts A.I. , one was a 6.5 x 47 and the "possible" was a .308. They were all 26" with various contours. Two of them were Rock Creeks and one was a Krieger. It mattered not what you put down the bore, as far as projectiles were concerned, they all just hammered, with almost no tuning! I think you could have run stones down those barrels and they would have hammered!

Having said the above, I do not believe that contour or length (that is length within reason) has very much to do with the accuracy potential of a given barrel. How the barrel steel was made, drilled, rifling cut and straightness of the barrel has more to do with the potential for accuracy than contour does.

This^^^

 

[M14AMU]

Heavy!!

 

[johara1]

I found the HV. @ 28" seems best and have no trouble with getting velocity and repeatable accuracy. Barrel quality is the key, and a hummer is the answer…. jim

 

[cdparker]

One thing that has come to mind is when designing the weight if a barrel; do you cut it with a taper or like some of the European designers do is to step the barrel from straight to straight. I have wondered if there was an advantage in doing it either way? As an example look at the Mauser 98K. Then The Browning Safari Rifles and some of the Anschutz barrels. Many years ago, Jack Davis lightened my magnum prone gun barrel for me and he did a step down rather than taper it. That gun got me lots of Perry trinkets, so I couldn't fault it. The last twenty years or so I have had tapered contour barrels that shot equally as well. My F-class barrel is a straight pipe. I am just wondering if there is any hard information on doing a taper contour compared to using a step down contour.
Just wondering
Craig

 

[M14AMU]

Screw the stepped taper!

Straight taper IMO only!!

 

[hogan]

Look at what the benchresters shoot! About 21.5" oal for best resonance. About 1.25" w/minimum taper

 

[mikegaiz]

The only thing I can add of any value here is my personal experience at shooting IBS 1000 yd. competition. I have shot 4 different cartridges in both Light gun and Heavy gun classifications. Meaning I shot the same cartridge in both classes with different taper barrels to make weight. The cartridges were, starting with 6.5/06 Ackley, 6.5/284, 300 WSM and latest 6.5/47 Lapua. All barrels were 30 in. finished length. All Light guns were 1.25 in. tapered to .90 in. All Heavy guns were 1.45 in straight no taper. Bottom line is that none of my Light gun barrels ever out shot my Heavy guns. 5 or 10 shot groups. :

 

[DennisH]

Over the last year or so I've listened to some who say that "XXX" is the best "profile" for accuracy in a given caliber.

My question revolves around the .308 using a 175 gr bullet (SMK, TMK, or even 178 A-Max).

One of the most accurate 308's I have is 26" long, 10 twist, Heavy Varmint (.90 @ the muzzle). I had them all the way to 31". A 28" barrel runs a close second.