Barrel Coning and Accuracy

[timM]

I am intrigued by the thought of barrel coning and can understand the loading advantages.  My question is, what are the before and after results in regards to accuracy after modifying the all important crown? 

Have any of you folks with coned barrels done a serious before and after test starting with an accurate rifle bagged up off the bench?  I don't discount the possibility of a rifle retaining its same accuracy, but I would be surprised if a guilt edge shooter (accurate rifle) could maintain that same accuracy after the coning procedure.  tim

[Nate McKenzie]

When I first started to cone barrels, I had four sighted in rifles with Getz barrels. I could detect no difference in group size or point of impact after coning. Of course this could have something to do with my 60+ year old eyes but I have done it for others and they were all happy.

[Longknife]

Tim, I have never noticed any accuracy loss after coning a barrel. Of course I was never a GREAT shot any way. I never did believe in hammering down bore sized or oversized balls, I thought the hammering would distort the perfectly round ball. If you are into this type of shooting then maybe coning is not for you, But if you are like most of us then I can tell you that you will not notice any decrease in accuracy, you can throw away the starter and ENJOY the sport!!!...Ed

(see my add for a great little coning tool in the "for sale" section here)

[Ken G]

I've coned a bunch of them and not seen any lose of accuracy but I'm sure not a serious target shooter.  I hate hammering a ball down the bore. 
I can say I saw one improve after coning.  It was a Cabela's Hawken,  it shot better groups after coning by about an inch @ 50 yards. 
If I was a serious target shooter or building a gun for a serious target shooter I don't think I would cone a barrel.  Why would you take a chance if all your shooting was at the range where pounding a ball down the bore wasn't an inconvenience. 
If you plan to shoot the gun in the field/hunting, then it makes for a much more enjoyable day. 
Ken

[Leatherbelly]

 I have one of Packdog's coned rifle barrels in a NE Tenn Mtn. B.Bean. I still use one of those non period correct short starters to start the ball. It shoots like a hotdamn!
Question to Ken. How deep did you cone this rifle in .40 cal.? I am guessing about 3/4 inch.
Tim M,
 I'm a trail walk,gong type shooter. Paper is not my forte. I can pick a spot on a gong and hit it out to fifty yards.Further out a hit is a hit. At first I was a little leery about coning but this rifle shows no loss of accuracy on any account.

[timM]

Gentlemen thank you for the input and replies.  I have a rifle that I will probably cone ......I feel better about it.

Someone once said "Only Accurate Rifles are Interesting" and as a life long shooter / hunter and competitor,  I have found that to be true.  I have always searched for a leg up on accuracy.  Every shooter I have seriously had any attachment to was special in the accuracy department.  Respectfully tim

[Daryl]

To cone, or not to cone - "THAT" is the question. whether t'is nobler - ah $#@*! - most people will see no change in accuracy with coning - great for them. Others, who are interested in the very best accuracy their barrel will produce, will not cone. That about sums it up. Using a starter is second natrue for us, we've always used staters.

 Oh yeah, mic'd LB's .022" patches yesterday and they were .012" wet and .013" dry. This just goes to show that the method used of measuring patches gives different results. One man's .020" is another's .015" - etc, so - when someone says he used a .020" patch, you have no idea what he's using.  Back to the subject at hand.

Some people think there is no changed in accuracy with coning, when indeed, they've never shot that barrel before it was coned, hense cannot make a comparrison of before and after,  the only way to tell if there was, indeed, a change.

I've coned and then removed the cone due to loss of accuracy. My .40 right now has a short 3/16" deep cone & it seems to work OK, but, I haven't benched it yet. It still needs a starter.

[Mike R]

intuitively, it seems that coning cannot help accuracy, only loading; so if you're going to use a short starter I see no reason to cone. If you are a reenactor of the 18th cent, there is little hard evidence that short starters were in use, so many have coned their rifles to ease loading [another 18th cent solution was to use a smaller ball].  I had only one coned rifle, a .40, and like Daryl said, I did not sight it in unconed, so cannot compare its accuracy before and after--it was "acceptable" after but who knows what it would have been?  As an old small bore competition shooter, I can only say that we did everything possible to keep our muzzles 'trued up'--to the point we never touched the muzzle with a cleaning rod. I guess a "perfect" cone might be OK, but otherwise I'll stick to a straight bore...

[Leatherbelly]

  Daryls,
 Are you going to go on and on about your righteousness or what? You are taking a measurement that covers about a quarter inch and cranking that micrometer down hard.Mine are spread over the width of my calipers. I think you are probably using 40 thou.LOL! I don't care what thickness you think I'm using, it works damnfine and we both shoot our rifles very accurately,nyet? No noticeable fouling and no wiping ad nauseum!

[Dphariss]

The last part of the barrel is the most important part, assuming the rest of the barrel is not screwed up. This is why some bench type RB rifles have false muzzles
Thus I distrust deep cones. Nor to I find then necessary for loading. A good smooth crown will load easily and not damage the patch is all that is needed.
If the ball/patch fit is loose enough to allow loading with just the rod a deep cone is not going change this.
If you have a tight fit its likely you will need a starter anyway. I see no gain over a good crown.
But some like them.
I tend to cone pistols deeper than rifles, I use the coning tools I have made to cut a "cone" about 1/8" long on the lands as a finish to the crown which I feel works better when cut with 2-3 angles somewhat blended together. Though with the right angle a single angle will work too. Pistols I will cone deeper *if they load hard* if not there is no reason to cone.
Talking is circles. Yes. There is no absolute answer.  When the ball starts without damaging the patch the crown is pretty much right.
When we start talking about the cones on original rifles we need to remember that they did not have modern rifling forms in most cases. The very narrow groove and very wide lands, often flat lands forming  6-7-8 sided bores, made for a different rifle than we shoot today. So the "crown" was also different. I also very much doubt they used tight ball/patch fits.
Later rifles (some any way) with different land groove ratios and more "modern" looking bores were also coned it would seem but then we must ask was it from necessity or habit? We we get into how the old timers did things we need to ask if its something that is desirable today or something they did to overcome some problem that existed, in this case, due to how they were making the barrels.
Below are photos of an apparently unfired Leman "Conestoga Rifle Works" rifle from 1840. The width of the lands would make this rifle very hard to load with anything but a loost ball/patch fit. Coned or otherwise.
Dan

[Daryl]

Good post, Dan - about those 6 and 8 sided bore shapes.  I might add, I've seen many pictures of muzzles that indeed had grooves in the corners of the flats that were redundant - not needed at all due to the hexagonal and octagon shaped bores.  In them, a loose ball patch combo would follow more readily than in a modern made, round-with-grooves, bore. In just a few shots, the grooves would be full of fouling and perhaps this was their purpose in those faceted bores- just as some later guns were made.

[Canute Rex]

Indulge me while I theorize for a moment.

A critical moment in the travel of a patched round ball is when it makes the transition between barrel and free air. One microsecond it is compressed in a patch and guided by the barrel - the next it is in free air with the patch falling away behind it. Obvious enough.

But what happens at that transition, when the band of contact around the equator of that ball is emerging from the bore? In a perfect world the ball, patch, and barrel are all absolutely symmetrical, and a flawless ring-shaped blast of hot gas emerges like an expanding doughnut behind the ball.

In an imperfect world, the patch is a bit uneven in thickness, weave, and lubrication. The ball is slightly out of round, as is the bore. That ring of gas behind the ball will be lumpy. The gas will start escaping sooner on one side than the other, or perhaps at several places. The ball will acquire a slight rotation or skew.

The more symmetrical the elements and the shorter that period of transition time, the smaller this effect will be. That's why people measure their patching material, use swaged balls, and use false muzzles to prevent wear. The perfect muzzle would be a sharp 90 degree cut, but try to load into that without a false muzzle.

Coning spreads out that transition, giving more time for any asymmetries to affect the flight of the ball. In a perfect world there would be no difference between a coned muzzle and a 90 degree muzzle, but that is not where we live. Of course, it is a continuum between a crown and a cone. How deep does a crown have to be before you call it a cone?

A shooter with consistently accurate components and a well coned barrel may never notice the effects of coning. A bench rest shooter undoubtedly would, because the margin of error is smaller in that competition.

It comes down to 1) the precision and symmetry of the coning, and 2) the consistency of the ball and patch. A coned bore would be more sensitive to variations.

Personally, I am going to stick with a crown and allow myself greater variability of components.

Canute

[hanshi]

[quote author=Canute

Coning spreads out that transition, giving more time for any asymmetries to affect the flight of the ball. In a perfect world there would be no difference between a coned muzzle and a 90 degree muzzle, but that is not where we live. Of course, it is a continuum between a crown and a cone. How deep does a crown have to be before you call it a cone?

Canute
[/quote]

Canute, I thought about this some and I'm afraid I'll have to disagree on this transition thing.   Seems to me a patched ball is either in contact with the bore or it's not.  At some point contact will be lost and the ball/patch combo will be free to mosey along on it's merry way toward the target.  Such a scenario (as you present) would appear to give the gases more opportunity, not less, to impinge on the ball.  Once the ball clears an undamaged muzzle the gases are free to scatter away from the ball.  With more room between ball and bore surface (short of freedom), the gases would have nowhere to go and would be forced back against the ball.  For this reason I believe coning to be an aid to loading, only, and not to accuracy.  If anything it would tend to hinder accuracy.  Any reports of improved accuracy after coning are anecdotal and probably due to the removal of barrel imperfections near the muzzle.

[Robby]

I will never, gulp, do it again. The directions Daryl has given on "crowning" are more than adaquite for starting a ball, plus it increases accuracy, because you can use a tighter ball patch combination.

[Daryl]

Canute - you kit the "ball" on the head wit your post- much more precisely than I could - I've posted similar, but less detailed info in the past, then tried coning myself- in two different barrels. Suffice to say that the closest one can come to the 90 degree crown, the better we are off, accuracy wise.

That is about guilt accuracy - few who shoot casually, tho, are interested in guilt accuracy - some won't use a load that seals as a stater is needed, while some use similar loads and declare all loads are as loose and therefore need a wad - some just don't care at all and as long as the ball comes out the muzzle and hits the target somewhere, they are happy. 

One need only needs to try deliberate shooting for accuracy to see the difference - that means a bench with proper bench techniques which is yet another leaning curve in this shooting game.

Some don't need it and coned barrels work just fine for them. They are not interested in hearing their rifles might not be as accurate as one without a cone, or that their ball/patch combo is a bit loose.  Some just can't seem to generate the force needed to seat a tight combination, even though it's more technique than force.  Some don't mind they have to wipe betweens hots or every #? of shots - some want to wipe - so be it. What we're trying to do is to steer those who want to improve their accuracy, to get the best their rifles can produce & for me, coning doesn't cut it.  Of coruse, 3 barrels isn't much of a test, especially when only 2 were shot before and after & the testing may have been slanted due to technique or lack of experimentation.

One thing I noticed concerning a cone on another man's rifle, is that it necessarily doesn't make loading a tight combination any easier than a short radiused crown even though a lighter patch combo was being used, when indeed, the opposite was the case.

[Dphariss]

Indulge me while I theorize for a moment.

A critical moment in the travel of a patched round ball is when it makes the transition between barrel and free air. One microsecond it is compressed in a patch and guided by the barrel - the next it is in free air with the patch falling away behind it. Obvious enough.

But what happens at that transition, when the band of contact around the equator of that ball is emerging from the bore? In a perfect world the ball, patch, and barrel are all absolutely symmetrical, and a flawless ring-shaped blast of hot gas emerges like an expanding doughnut behind the ball.

In an imperfect world, the patch is a bit uneven in thickness, weave, and lubrication. The ball is slightly out of round, as is the bore. That ring of gas behind the ball will be lumpy. The gas will start escaping sooner on one side than the other, or perhaps at several places. The ball will acquire a slight rotation or skew.

The more symmetrical the elements and the shorter that period of transition time, the smaller this effect will be. That's why people measure their patching material, use swaged balls, and use false muzzles to prevent wear. The perfect muzzle would be a sharp 90 degree cut, but try to load into that without a false muzzle.

Coning spreads out that transition, giving more time for any asymmetries to affect the flight of the ball. In a perfect world there would be no difference between a coned muzzle and a 90 degree muzzle, but that is not where we live. Of course, it is a continuum between a crown and a cone. How deep does a crown have to be before you call it a cone?

A shooter with consistently accurate components and a well coned barrel may never notice the effects of coning. A bench rest shooter undoubtedly would, because the margin of error is smaller in that competition.

It comes down to 1) the precision and symmetry of the coning, and 2) the consistency of the ball and patch. A coned bore would be more sensitive to variations.

Personally, I am going to stick with a crown and allow myself greater variability of components.

Canute

Like I said the people REALLY CONCERNED WITH ACCURACY use false muzzles and no crown on the barrel.
Bullet guns will shoot best with NO crown at all.
But this will not work with a ML unless it has a false muzzle.

Dan

[northmn]

Generally the type of crowning is related to the ability to load the most accurate loads.  The vast majority of loads used in rest matches on paper, such as X sticks or bench use a ball that either will just fit in the lands or slightly larger and the use of heavier patching.  They have to be short started, period.  Whether coning would be as accurate with a short started load of that nature, I do not know.  Part of the reason a false muzzle is used is to prolong the barrels life as it takes the muzzle wear and not the muzzle.  They also permit more aggressive loading practices to achieve their very precise groups.  There has been discussion of the historical use of loading blocks and when they may have come into use.  A revolutionary war rifleman for instance,  may have had a coned muzzle to permit faster loading with less fumbling.   You meet quite a few shooters that do not like short starters, as they are an extra step in loading.  A coned muzzle may permit a tighter patch combination than a standard muzzle and be in between.  Mostly this type of loading, either loading blocks or coned muzzle, requires a smaller ball than a short started one, which is by nature slightly less accurate.  In my 54, I use a 535 ball with a short starter but have to use a 530 in blocks or if I want to just use the ramrod and the seater installed on my knife handle. 

DP

[dave gross]

Why is it that we spend energy in an almost anal quest to make these rifles resemble as closely as is possible their ancestors and then tote around a short starter (seldom if ever found in old acoutrement collections) to shoot the things.  If one hole accuracy is your thing then go with a false muzzle, if not cone the !@*%&@ muzzle and enjoy ease of loading.  All the results posted here are for the most part anecdotal, both pro and con, so I will add mine.  My 45 Getz with a deep cone in the muzzle, using my hunting load of a .433 ball and .015 patch shoots one ragged hole at 50 yards off a bench under ideal conditions.  I can never equal this offhand but find this to be acceptable accuracy for hunting.  $#*!, my brother with his 264 Remington 700 and a Leupold scope can't tack drive offhand. 

Dave Gross
Way down east in Maine

[Mike R]

Why is it that we spend energy in an almost anal quest to make these rifles resemble as closely as is possible their ancestors and then tote around a short starter (seldom if ever found in old acoutrement collections) to shoot the things.  If one hole accuracy is your thing then go with a false muzzle, if not cone the !@*%&@ muzzle and enjoy ease of loading.  All the results posted here are for the most part anecdotal, both pro and con, so I will add mine.  My 45 Getz with a deep cone in the muzzle, using my hunting load of a .433 ball and .015 patch shoots one ragged hole at 50 yards off a bench under ideal conditions.  I can never equal this offhand but find this to be acceptable accuracy for hunting.  $#*!, my brother with his 264 Remington 700 and a Leupold scope can't tack drive offhand. 

Dave Gross
Way down east in Maine

can't deny anything you said....when I was 'raised up' as we say down south, it happened to be in Penna...in the 50s/60s when one hole precision was the ultimate goal of all riflemen I knew--from a bench of course, that is how one tests precision of the gun.  This has nothing to do with accuracy offhand--accuracy is the ability to hit the target, precision is how close the bullets space on target. IF your gun is precise and sighted in, then any inaccuracy is the shooters fault [or maybe a high wind gust, etc.] . The desire for precision is so that parameter is removed from the accuracy equation.  The question becomes how imprecise is acceptable?  When I was a small bore competitor we tried for X's all the time [no bench]--ANYTHING that could upset precision was avoided.  Clearly in the MLing community there are varied opinions and uses of our guns.  Each to his own as my 'ol pappy used to say...

[northmn]

 This has nothing to do with accuracy offhand--accuracy is the ability to hit the target, precision is how close the bullets space on target. IF your gun is precise and sighted in, then any inaccuracy is the shooters fault [or maybe a high wind gust, etc.] . The desire for precision is so that parameter is removed from the accuracy equation.  The question becomes how imprecise is acceptable?  When I was a small bore competitor we tried for X's all the time [no bench]--ANYTHING that could upset precision was avoided.  Clearly in the MLing community there are varied opinions and uses of our guns.  Each to his own as my 'ol pappy used to say...
[/quote]

Always wondered if someone would bring that up.  Technically accuracy is in the sights and precision in in the load/ barrel as stated.  Considering that most ML's are shot with open iron sights, most are as precise as needed with that sighting equipment.  To get the most out of a target rifle off X sticks you need sophisticated peep sights (as you do for long range BPC) .   A lot of our use today is on the target range where precision is necessary, even in off hand.  Also there is the theory that the precision capabilities of the rifle compound the accuracy problems of the shooter (in actual practice they may upon occaision compensate)   Most target matches have an aggregate of 25, 50 and 100 yard scores.  About any rifle will shoot well at out to 50 yards with a reasonable combination.  At 100 very few shooters can take advantage of the precision capabilities of the rifle.  I used to win aggregates because I practiced at 100 yards.  To stay on track for this thread, I am willing to bet that a coned muzzle will outshoot most offhand shots at 100 yards.  At 50&100 yard X-sticks you had better use a short started load.  If you are shooting a 1 1/8 inch barreled heavy over the log gun, then the coned muzzle may not be for you, but using a 13/16 40 or 45 you may not see much difference.

DP

[Daryl]

BUT - without precision, there can be no accuracy.  If a rifle is only capable of shooting a 3" group, and you have 3" accuracy capability, you will not shoot a 3" or even 6" group, you will shoot up to a 9" group.

[Dphariss]

BUT - without precision, there can be no accuracy.  If a rifle is only capable of shooting a 3" group, and you have 3" accuracy capability, you will not shoot a 3" or even 6" group, you will shoot up to a 9" group.

Exactly.
Assuming the owners cannot shoot accurately is not a reason to produce inaccurate firearms "since they will never know the difference".

To expound somewhat on Daryl's points.
2 rifles.
#1 shoots 6" groups at 100 yards. 3" radius from the point the barrel is aimed at.
 #2 shoots 1" groups. 1/2" radius.
If the shooter breaks the trigger with #1 pointed 3" from center the ball will strike some place between center and 6" from the center.  If he breaks it center it will strike somewhere within 3" of the aiming point.
#2 will place the 1st shot within 1/2" of where the barrel is aimed. It will hit the center on the second shot.
The poor rifle has a *chance* to hit the "X" even if the shooter is off somewhat. So sometimes the less accurate shooter will get an "X" when he was actually 2-3" off target.
The good rifle will only hit the point its is aimed at or very near too it. It is entirely possible for the shooter of the poor rifle (with luck)  to beat the shooter of the good rifle in a contest of 1-2 shots. This does not make the 6" group rifle better than the 1" group rifle. It just tells me that the shooter of #1 is lucky.

I have never heard a shooter bragging about how inaccurate his rifle was. There is a reason for this. Inaccurate rifles are an abomination to a serious shooter.

Dan

[rdillon]

OH MY GOD!  This is primitave black powder shooting, isn't it???

Why must we get so techinial on this subject.

My head hurts now!!!!!!!

[Mike R]

BUT - without precision, there can be no accuracy.  If a rifle is only capable of shooting a 3" group, and you have 3" accuracy capability, you will not shoot a 3" or even 6" group, you will shoot up to a 9" group.

that is incorrect strictly speaking from a statistical viewpoint:  if your rifle shoots a 3" group ["imprecise"] but the group exactly centers the bull, it is accurate.  If that same accuracy is obtained with a 1/2" group it is both accurate and precise. 

[Mike R]

OH MY GOD!  This is primitave black powder shooting, isn't it???

Why must we get so techinial on this subject.

My head hurts now!!!!!!!

the cure for that is about three fingers of kentucky joy juice.