honing of super-accurate rifle barrels

The proof will be in the targets.

There are a lot of assumptions being made, when you read the article, it sounds like that the current manufacturers are not already striving to eliminate as many anomolies as possible.

"Smootheness" seems to be the big selling point. The author is assuming a lot in that 'smoothness' will solve many problems, when in fact the entire concept might allow others to crop up.

That statement about an ordinary AR style Rifle having the same accuracy potential as a super precision Bolt Gun seems a little niave. Granted, the barrel is the heart of any extreme accuracy set-up, but there is a little more to it than that.

Like I said, the proof will be in the targets..........jackie
 
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I tend to agree with Jackie on this. I can see where the guy is headed, and it certainly is great marketing. However, all the honing in the world doesn't change the fact that when it's all done, you need to go back in there, rifle the barrel and lap it. So, you either need to cut more material, or swage it. But it's one or the other. Then, using the 150 grit lapping compound isn't exactly going to help that ~8 micro finish you have on the lands.

I'd be interested in knowing how honing is going to make a bore straighter. I know, honed holes are usually pretty straight. But I'd never heard of a honed hole that was 100x as long as its diameter. That's a bit of a stretch to assume you could remove a curve in that long a part if one should exist. Even if only removing part of it, I'm skeptical. So, unless this hone is a lot longer than I think it is, I think that claim may be exaggerated a bit. I don't know for sure though.

I'll admit the idea sounds cool, but I'm not sure I believe it will help in a practical sense. Furthermore, if someone thinks a barrel will make a 1 hole gun and that the projectile has no say in the group size, they've got another thing com'n. I like the statement about the Ruger Semi Auto 22 Mag at 50 yards shooting 'almost' one hole groups. Sad to say, but that's not gonna impress many here. Unless "near single hole" means, near shooting 0's. If near single hole means any two bullets not touching, then I might not have saved those targets.

If someone with one of these barrels all of the sudden starts trouncing the competition in the competitive BR world, this guy will have his door broke down, and price will be no object. (I'm thinking it might not be now)
 
Makes one wonder, how many shots before the super finish looks like any other good finish.
 
A reamer has a relatively short cutting area. When it finds a kink or abrupt turn in the barrel left from the gun drill it will tend to follow it. The hone has a longer cutting surface and will bridge across these areas making a straight hole. I have seen many posts on this forum about these kinks when indicating a barrel for chambering. Even with a abrasive length shorter than the barrel length the hone will start to remove any banana shape, but probably not all in the amount being honed from gun drill to rifling.

The hone will remove the kinks and make a straight (size end to end) round hole with a good finish. With those traits you will have consistently better barrels.
 
Now that I agree with.

Nothing is more aggravating than to have one of those "kinks" right where the throat forms.

I have never seen a custom barrel with a 'bannana' bend, that is, a constant curve. The runnout is alway attributed to several of thos 'kinks" that meander through the bore, some going the opposite way of ones before............jackie
 
it sounds good...and he has a track record.....so i'll do a wait and see.....(sounds expensive)


jackie..where did you see a reference to ar''s...i read it twice and did not see it....

i do have ar's that shoot well..in br terms....

mike in co
 
My mistake, Mike. He referred to 'inexpensive semi-autos shooting on the same level as expensive target rifles'. I see now he was referring to 22 rimfires, not AR Platformed centerfire Rifles........jackie
 
Because of so many factors that affect accuracy I doubt a semi auto rim fire will ever compete with a bolt action rim fire... to start with a rim fire's semi auto's chamber/throat can not be as tight as a bolt action... and a lot of accuracy is right there...

Hard to imagine the honing process in long little holes...
 
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why....
i have a supprise for you..i have three ar's with br type chambers....(ok, 2 1/2)....308 win br in an ar10, 223 min spec short throat in an ar15, and a 6beggs in an ar15.
my ar10 shoots under .2 and small group of 0.116.....
my problem is i cannot do five record shots with sighters in under 7 min...i'll get there.
so for now i shoot club matches.
mike in co

Dennis Sorensen said:
Because of so many factors that affect accuracy I doubt a semi auto rim fire will ever compete with a bolt action rim fire... to start with a semi auto's chamber/throat can not be as tight as a bolt action... and a lot of accuracy is right there...

Hard to imagine the honing process in long little holes...
Click to expand...
 
Honing is just the icing on the cake really. In my experience getting a barrel bore as true as possible has more to do with properly stress relieving a blank first, drilling it as straight as possible, rifling as evenly as possible, and then profiling the blank down to size at a modest enough feed that the mid-section is not bowing too much away from the cutter. It is the combination of all things resulting in a well-centred and symetrical barrel/bore, which will provide the results looking for if straightness is the main aim. Sure, a long-ish hone will help to remove anomalies before rifling and minimise cutter or button 'bumps', but i think the emphasis there may be more on honing there may be more of a promo for sunnen?

Jackie, I have seen plenty of 'banana barrels'. If you cut a cross section off (in the middle) it is common to see the wall section of the barrel thicker on one side than the other. Some barrels i have found the bore off-center by as much as 0.030"-0.050". No kidding.
 
Kiwi, you can go 4 inches in either direction, and there is a good chance that the off center will not be in the same proportion, or even in the same plain.
I stand by what I said. I have done hundreds of custom barrels, and have never seen one that had a bannana curve that was consistant throughout the bore. All, however, exibit, to varying degrees, spots in the ID where the Gun drill, for what ever reason, meandered one way or the other.

If you think about the very nature of gun drilling and the way it works, one of the more improbable senarios would be a hole that was a constant curve. You would have to say, "how did it do that"? Not very likely.

In the current manufacturing of Rifle barrels that are not produced by a hammer forged method, everything is predicated on the initial gun drilling of the blank. No reaming, lapping, rifling, or anything else will correct any flaws in straightness that are a result of this proccess. The only thing that will correct it is either some type of single point boring, (obviously not practicle), or a honing proccess, which as the OP pointed out, can produce a perfectly straight hole. That is, if the technology has truly advanced to the point to where this type of honing is practicle in such small holes of such great length.

One problem is that in order to have stock for the hone to remove and accomplish it's purpose, the initial gun drill must produce a hole that is withing that .005 to .006 of being straight with its self for it's entire length. Any sopts outside that perameter will leave a shadow of different diameter. From my experience, this is no easy task unless you are willing to accept a rather high scrap rate.

I am intrigued by this. ........jackie
 
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Wasn't there a company (Blackstar ?) that promised super straight/micro polished bores that were going to revolutionize Bench Rest shooting? They came and went and nobody seemed to notice (or win with them)
 
Karl, they were just pouring perfume on the pig. All of their micropolishing and what ever still left the bore with those anomalies of unstraightness.

I could tell you a great story about that bunch, but I have to go to lunch right now.........jackie
 
I wonder if EDM could be used to produce straighter bores. I see that Butch Lambert asked the same question on Practical Machinist several years ago. In principle, it seems possible. The machining forces, in a traditional sense, are essentially zero, thus no deflection of the tool, though vibration induced by the sparks might cause some movement. Machining with the blank vertical would eliminate gravity from the equation. One could tip a lathe bed on its end to get enough vertical travel, and set up an experimental cut.
 
jackie schmidt said:
Kiwi, you can go 4 inches in either direction, and there is a good chance that the off center will not be in the same proportion, or even in the same plain.
I stand by what I said. I have done hundreds of custom barrels, and have never seen one that had a bannana curve that was consistant throughout the bore. All, however, exibit, to varying degrees, spots in the ID where the Gun drill, for what ever reason, meandered one way or the other.

If you think about the very nature of gun drilling and the way it works, one of the more improbable senarios would be a hole that was a constant curve. You would have to say, "how did it do that"? Not very likely.

In the current manufacturing of Rifle barrels that are not produced by a hammer forged method, everything is predicated on the initial gun drilling of the blank. No reaming, lapping, rifling, or anything else will correct any flaws in straightness that are a result of this proccess. The only thing that will correct it is either some type of single point boring, (obviously not practicle), or a honing proccess, which as the OP pointed out, can produce a perfectly straight hole. That is, if the technology has truly advanced to the point to where this type of honing is practicle in such small holes of such great length.

One problem is that in order to have stock for the hone to remove and accomplish it's purpose, the initial gun drill must produce a hole that is withing that .005 to .006 of being straight with its self for it's entire length. Any sopts outside that perameter will leave a shadow of different diameter. From my experience, this is no easy task unless you are willing to accept a rather high scrap rate.

I am intrigued by this. ........jackie
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I was told about a bad experience by one barrel maker - the steel blank stock that turned up was slightly bent in transit, or had been stressed. He found that after machining and making the first batch of (new steel) barrels they all looked good and straight, but after final 'stress' relieving they reverted back to their original shape. He then had some expensive long steel-banana souveniers - (or expensive scrap steel). After that he modified the process to include mulitple stress reliefs, as well as making a skim cut on the barrel OD once turning between centers. Steel 'memory' and also little hard spots can torment a barrel maker if the steel supplier drops their product quality or consistency.

P1000979.jpg

Attached is a cross section of a 'chinese' barrel being threaded for a silencer. The bores centerline was off by something insane like 0.050" from memory??
 
All were fired from 50 yards using a semiautomatic Ruger .22 magnum rifle equipped with one of his barrels. Shooters familiar with this rifle and cartridge know this accuracy is extraordinary,
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Yup, those 22RF Magnums are "reference" accurate.......Why do folks invest hundreds of thousands of $$, move entire factories, claim to be world leading experts, and then use something like this to validate it all?
 
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