Author Topic: Barrel Coning and Accuracy  (Read 34309 times)

Daryl

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Re: Barrel Coning and Accuracy
« Reply #25 on: April 08, 2009, 10:12:43 PM »
  if your rifle shoots a 3" group ["imprecise"] but the group exactly centers the bull, it is accurate.  

That statement is incorrect - a rifle that shoots a 3" group is not accurate.

As stated many times before, accuracy is in the eye of the shooter.  Remember the fellow with a .50 'italian or Spanish something' - he filed the rims off .30/30 range salvage brass, filled them with sand and a wax plug - hitting the 25 yard target several times out of 5 shots, he claimed excellent accuracy!

rdillon

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Re: Barrel Coning and Accuracy
« Reply #26 on: April 08, 2009, 10:54:25 PM »
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!!!!!!! ;D

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

Sounds Good!!!!!!!!!

Offline Blacksmoke

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Re: Barrel Coning and Accuracy
« Reply #27 on: April 09, 2009, 01:24:43 AM »
I am with Canute, Dan and Daryl on this one!  Maybe it's time to break out the "proofing bench" and settle ,once and for all, the question "does coning effect accuracy to the negative"? I have never shot a coned barrel- having said that- my barrel rifling savvy from29yrs. experience rifling RB barrels, tells me that it DOES effect accuracy to the negative- by how much I am not sure. I think the same principle is involved with trying to shoot an accurate group with "5" groove rifling.  Has anyone on this forum ever tried to shoot a barrel with "5" grooves?  It just doesn't work because  there are not enough lands to keep the ball centered and during the "transition period" the hot gasses will always go to one side of the ball and patch or the other- thus throwing the projectile off course !  But I do think that we have to differentiate between "survival" on the frontier and "competition bench rest" shooting at Friendship.       My thoughts,    Hugh Toenjes
« Last Edit: April 09, 2009, 04:14:14 AM by Blacksmoke »
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northmn

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Re: Barrel Coning and Accuracy
« Reply #28 on: April 09, 2009, 02:00:47 AM »
Technically speaking a rifle shooting a 3 inch group is not precise, not inaccurate.  It is accurate if it centers the bull.   Most use the term accuracy in referring to group size, which is not correct. Its a little technicality in some shops.   A scope is precise if every click moves the group the same distance.  It may not be accurate as far as saying the distance is 1/4" per click.  A rifle that is capable of 1" precision but shooting a foot to the left is inaccurate.  Its one of those things shooters have been doing for so long that we know what they mean anyway. 
As Dave G. pointed out his rifle with a coned muzzle shoots into a ragged hole at 50 yards off a bench, so that he has the precision to move the sights to any point he wants for accuracy.  Generally pretty fair precision can be obtained with a good ball and powder patch combination that may load a little easier. Also, with the accuracy of primitive fixed sights one may not be able to take advantage or know how precise the rifle is.  Those of you who work on getting very precise loads know that there is a point of diminishing returns where you are not cutting off inches but fractions of an inch by weighing ball, using tighter combinations and so forth.  Getting a 2" group at 100 yards may not be difficult, cutting it down may take a lot of adjustment.  It also requires better sights.  Bullseye shooting for score has given us the false muzzles, tight loads and some innovative "primitive" sights.  Some of the "primitive" matches where a target is scored if hit may not require that level of accuracy or precision.  I have shot more squirrels under 25 yards than over, and a lot of deer are shot under 75 yards. No one would argue that there is anything wrong with shooting a rifle with the precision capabilities of say 1" at 100 yards, its just that one may not really be taking advantage of it and may do as well with less. 

DP 

D. Bowman

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Re: Barrel Coning and Accuracy
« Reply #29 on: April 09, 2009, 03:12:18 AM »
I think we are all way over thinking this. Isn't a cone nothing more than long crown and if done with precision why would it be any less accurate than a conventional crown done with the same precision??

                                                      Duane Bowman

Mike R

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Re: Barrel Coning and Accuracy
« Reply #30 on: April 09, 2009, 03:21:41 PM »
  if your rifle shoots a 3" group ["imprecise"] but the group exactly centers the bull, it is accurate.  

That statement is incorrect - a rifle that shoots a 3" group is not accurate.

As stated many times before, accuracy is in the eye of the shooter.  Remember the fellow with a .50 'italian or Spanish something' - he filed the rims off .30/30 range salvage brass, filled them with sand and a wax plug - hitting the 25 yard target several times out of 5 shots, he claimed excellent accuracy!

As I and northmn stated, technically [and in scientific circles] accuracy and precision are two different concepts--it involves statistical thinking.  a gun can be precise if it groups its bullets tightly, but be inaccurate if the sights are off and the tight group is off to one side or low, etc.  A gun can be accurate yet imprecise if its bullets group so as that the center of the group is the x ring, even if its group is scattered.  Informally, many riflemen use accuracy to mean precision, but technically it does not.  A shotgun can be an accurate weapon even though it is not precise in its spread of shot--a rifle needs to be both precise and accurate to be acceptable.  In the case of a rifle, accuracy is a function of sight alignment and ability of the shooter.  Precision is a function of the bore and load.   

Daryl

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Re: Barrel Coning and Accuracy
« Reply #31 on: April 09, 2009, 05:08:33 PM »
Uh huh - I like to have the precision to be able to accurately put the bullets in the centre of the target. Without both, one stands few opportunities to be in the winner's circle.  The odd time, someone lucks into that spot with neither precision nor accuracy, but it takes both precision and accuracy to be consistant.

The X ring on a deer, elk or moose his huge - lucky for most hunters I've had the pleasure, sometimes displeasure of seeing and hunting with.

Mike R

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Re: Barrel Coning and Accuracy
« Reply #32 on: April 09, 2009, 05:52:35 PM »
Uh huh - I like to have the precision to be able to accurately put the bullets in the centre of the target. Without both, one stands few opportunities to be in the winner's circle.  The odd time, someone lucks into that spot with neither precision nor accuracy, but it takes both precision and accuracy to be consistant.

The X ring on a deer, elk or moose his huge - lucky for most hunters I've had the pleasure, sometimes displeasure of seeing and hunting with.

Exactly. :)

Offline Blacksmoke

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Re: Barrel Coning and Accuracy
« Reply #33 on: April 09, 2009, 05:59:28 PM »
Hey Guys - NON of these barrels were CONED! ;D       Hugh Toenjes
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Offline hanshi

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Re: Barrel Coning and Accuracy
« Reply #34 on: April 09, 2009, 06:46:39 PM »
After thinking about it, I mostly agree with the accuracy/precision concepts described and discussed.  I would speculate that my question, then, is more philosophical than technical; ergo, does a rifle become less/more accurate when passed from one shooter to another?
!Jozai Senjo! "always present on the battlefield"
Young guys should hang out with old guys; old guys know stuff.

Offline Blacksmoke

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Re: Barrel Coning and Accuracy
« Reply #35 on: April 09, 2009, 07:10:32 PM »
Flintr-   There are some barrels on the firing line that just won't shoot accurately no mater who's pulling the trigger!  I have proven this time and time again.   Not all barrels are created equal-- Even from my rifling bench--some are more accurate than others!  If an improperly rifled barrel won't hold a group on the proofing bench then it will not matter who tries to shoot it. The result will be the same--no group.   The problem lies with the "rifler" not the shooter!  When I "proof" a barrel the "shooter" has been eliminated from the equation.  The skill of the "rifler" is being tested!        Hugh Toenjes
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Offline hanshi

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Re: Barrel Coning and Accuracy
« Reply #36 on: April 09, 2009, 09:42:22 PM »
Blacksmoke, I like your answer.  When I talk about an accurate rifle I'm referring to what the gun can do sans the human element.  Practice can make a shooter "more accurate" but the gun can't do that.  I may not be technically correct in this but "mechanical" accuracy is what I mean when I speak of rifle accuracy.
!Jozai Senjo! "always present on the battlefield"
Young guys should hang out with old guys; old guys know stuff.

Offline D. Taylor Sapergia

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Re: Barrel Coning and Accuracy
« Reply #37 on: April 09, 2009, 10:13:26 PM »
Hugh, this is your golden opportunity to do a scientific (mechanical) test - of coning.  Take a barrel that produces a ragged hole at 100 yds.,  cone it, and shoot it again.  Post the results.  Many of us would be most interested.
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northmn

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Re: Barrel Coning and Accuracy
« Reply #38 on: April 09, 2009, 10:20:16 PM »
Look at it this way.  You are shooting at a target with a 1" ten ring so you want an accurate enough rifle to hit a 1 inch circle with all shots.  To do so a rifle that averages 1 inch groups will fall short.  First, the 1 inch groups are an "average" and will include larger groups so that the rifle/load will have to be able to group tighter than one inch to do so.  If the high is 1 1/4 inch in the average then you will need a 3/4 inch group to allow for deviation.  Also sights do not always permit a dead center sight in.  You may have a group slightly off center.  All in all to get an accuracy level of 1 inch to hit a one inch circle you may need a precision level of less than 3/4 inch.  Kind of an elaboration of Daryl's point.  One reason to look at them as two different entities.  To the best of my knowledge no one has ever been thrown out of a shooting club using the term accuracy for precision, but it helps to understand a difference.    As to a coned barrel, how loose do they shoot compared to a regular target barrel, or a barrel that is not loaded for targets.  I am reminded of a Douglas barrel I had that had 10 ring capabilities at the ranges I shot, but was mismarked for run out and would shoot to one side at 25 yards and another at 100 if sighted in for 50 yards.  Precise enough but not accurate.

DP

Offline Canute Rex

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Re: Barrel Coning and Accuracy
« Reply #39 on: April 09, 2009, 10:35:22 PM »
Hugh, D. Taylor S. took the words out of my mouth, er, off of my keyboard. I was thinking of building a proofing stand and buying a barrel to do it myself, but you have the right setup already.

It would be interesting to see the results for a variety of powder loads and patch/ball combinations. Does a coned bore start to open up faster with heavier loads than a crowned muzzle? Or with lighter loads? Thick patch vs. thin? Hmm, sounds more like a career than an experiment.

I'll stick with my initial theory. In a perfect world where everything is flawless and perfectly symmetrical, cone and crown would be equal. In the real world of variable patches and balls, a coned bore will be more susceptible to those variations. If a shooter with an accurately coned barrel uses good swaged or accurately cast balls and tight, fine, uniform patching, those variations may get lost in the variables of the shooter/environment/rifle and never get noticed. But they may show up with the barrel in a proofing stand, or if the shooter gets careless.

Canute

Offline hanshi

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Re: Barrel Coning and Accuracy
« Reply #40 on: April 10, 2009, 12:33:18 AM »
Given the sights on most muzzleloaders you can expect the guns to outshoot the shooters the majority of the time.  If I can shoot well enough, let's say, to hold all shots in a 2" circle, and my rifle is capable of holding all shots in a 1" circle, then, I'll have better scores than if my rifle can only hold 3" groups.  I'll know that all shots will be 2" or under.  At the distances I shoot I sight my rifles to shoot above poa.  I don't think this makes them inaccurate.  Now, this is just MY idea of accuracy as I don't split the accuracy/precision hair.   It's not a technical definition, of course, but a sort of "everyday" definition.  I would guess that this is the way most folks would think of accuracy.  I'm not an engineer, just a hunter and field shooter.  I agree that determining the effect of coning on accuracy (precision, if you will) would be to design the experiment to remove all (possible) variables and use the number of bbls to get a statistically significant result, if there is one.
!Jozai Senjo! "always present on the battlefield"
Young guys should hang out with old guys; old guys know stuff.

Offline Don Getz

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Re: Barrel Coning and Accuracy
« Reply #41 on: April 10, 2009, 01:30:12 AM »
Shouldn't these two terms be considered the same.   I don't think one normally uses the term "precise" to describe how
well this gun shoots.  Usually it is an accurate gun or it isn't.  On the other hand, if it is a so called "precise" gun, it is also
an accurate gun, unless someone is so stupid that he can't adjust the sights.  If you must use the term, if a person can
shoot a gun "precisely", he can also shoot it "accurately"..........Don

timM

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Re: Barrel Coning and Accuracy
« Reply #42 on: April 10, 2009, 01:39:08 AM »
Great comments all around, with most of what I've read concerning precision and accuracy is regarded as fact in my world. The terms "Precision and Accuracy" do seem to over lap (look it up).  So..........a "Precision Rifle and Ammunition" gives greater opportunity to do accurate shooting!

This is all comparative, but I think that most serious ML shooters could probably agree on basic bench marks for a muzzle loading rifle to be considered "accurate"

So IF the "Coning" procedure took a rifle capable of 4 MOA repeatability @ 100 yards and turned it into a 6 MOA shooter (not saying it would) and now a joy to load and shoot.........I think a Squirrel at 20 yards or a Whitetail at 70 yards would not know the difference.

There remains application for uncompromising accuracy from ones shooter.  Competition and hunting immediately comes to mind.  Personal Deer hunting experience, (Rocky's to the West Coast) longer shots are the norm and to be a successful ML hunter a precision rifle and ammunition combined with good range estimation = success.

Iron sights and accuracy is a confidence game.  I think a lot of casual shooters might be surprised at what is possible with iron sights.  Consider the 600 yard prone aspect of a NRA High power  or Military rifle match.  The 36" bull is typically hiding behind about half the width of the front sight.  tim
« Last Edit: April 10, 2009, 01:40:58 AM by timM »

Daryl

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Re: Barrel Coning and Accuracy
« Reply #43 on: April 10, 2009, 04:51:49 AM »
Taylor's suggestion certainly has merit - however - to establish if coning hurts the accuracy, one must start again and work up a new load for the coned barrel.  Merely using the previous load won't cut it - various patches, ball sizes and powder charges plus different granulation's must also be tried for it to be a fair trial.  My trials weren't quite fair to the coned bores.  I was happy with the speed ie: powder charge and patch thickness thus loading prior to coning the barrel's muzzle approximately 3/8" deep - it wasn't deeply coned.  There were coned evenly.  I changed only the muzzle and obtained roughly double the group size using the existing 'accuracy' load.  Had I raised the charge or dropped the charge, I may have obtained the original accuracy/precision - thus making both muzzle shapes equal in their precision/accuracy.  I'll just call it accuracy from now on.  You know now or is it now know I also mean precision. ;)  Now, the accuracy I achieved with the coned muzzle was more than necessary to hit any targets we have, right to 100 yards, and indeed, was still fairly good - opening to from 1" to 1 1/8" at 50 yards, in both the .40 and .45.  I wasn't going to do this with the .40 after the .45's failure to maintain accuracy, but thought I'd give it a whirl.  Test loads were shot off the bags over a period of several months to test repeatability.

As I said, reducing nor increasing powder charges was tried.  With my original loads, I didn't find any easier loading, either as after the patched ball is seated 3/4" down the tube, it is swaged to groove diameter and thus loading is virtually identical, before and after.  It still took a punch of the rod to get the ball down into the rifling.  I was able to seat the ball flush with the muzzle with my thumb, but the short starter was still required to punch it into the lands and down 6" for the wiping stick to seat it the rest of the way, onto the powder.

Offline Dphariss

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Re: Barrel Coning and Accuracy
« Reply #44 on: April 10, 2009, 07:11:00 AM »
Shouldn't these two terms be considered the same.   I don't think one normally uses the term "precise" to describe how
well this gun shoots.  Usually it is an accurate gun or it isn't.  On the other hand, if it is a so called "precise" gun, it is also
an accurate gun, unless someone is so stupid that he can't adjust the sights.  If you must use the term, if a person can
shoot a gun "precisely", he can also shoot it "accurately"..........Don

Exactly.
Any attempt to make a distinction between accurate and precise as related to a barrels ability to group shots is a play on words.

Dan
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northmn

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Re: Barrel Coning and Accuracy
« Reply #45 on: April 10, 2009, 04:24:51 PM »
I have a neighbor works in a machine shop that is very aware of the difference between the two terms.  A measuring device readings is considered precise, but its accuracy is in terms if variance off a standard, say within .0001 of an inch.  If the variance is maintained through out its range of use it is precise.  As I stated, I had a barrel that grouped well, precise, but had a runout such that it wanted to shoot to one side at close range and another at longer range. It was not accurate barrel except at one range.  It is kind of like calling an adjustable wrench a Crescent wrench.  In some shops you will be called on it.  Most of us use the terms intercheangeably and get by fine.  Common usage has given the term accuracy to mean the same, but there is a difference in meaning.  As to adjusting sights, you rarely will get sights adjusted to dead center of a group on target, such that a one inch group will fit exactly in a one inch circle.  Close, but rarely exactly.  Thats why good quality adjustable sights cost what they do.  I have had fun with this concept and even thought about introducing it as a thread but did not because I really did not see the differences as all that important.  Its relevance mostly lies with the mit-picking rest type target shooting where a gain of a quarter of an inch in group is something celbrate over lobster and fine wine.  As the late Frank Marshall stated about deer rifles, "you only need to hit a deer, not cockroaches at 100 yards".

DP

Daryl

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Re: Barrel Coning and Accuracy
« Reply #46 on: April 10, 2009, 05:54:29 PM »

DP- have you not shot the flybuster Bench Rest target?  That's a target with 6 house flys on it - 5 for a head, 3 for a body and 1 for a wing or leg? The one in the centre of the target is the sighter for checking wind drift.  Put a scope on that old .69 I had and it would get a 5 every time - off the bags - they'd have to give a 5 (or 8? ;D) for the gaping hole where the fly used to be.  That's accuracy - or is that precision?  :-\

Offline Blacksmoke

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Re: Barrel Coning and Accuracy
« Reply #47 on: April 10, 2009, 08:13:42 PM »
Hey Guys,  I've just been reading the last number of postings on the thread of the effects of coning and
precision versus accuracy - my head hurts?!  ???  What amazes me are the opinions of people who have never rifled a barrel let alone proofed it on a proofing bench.  I know that I said "maybe I should break out the proofing bench and settle this controversy once and for all".  But why should I ruin one of my perfectly good "premium" barrels by coning it when I already know what effect it will have on its accuracy?!  It will make it less accurate.  Yes, it will load easier, but then so will a .050" under size ball and no patch!!  So for me to conduct the suggested experiment would be a waste of time on my part.  And why would you believe the posted results any more than you believe the presently posted results of my proofing?  However, if someone or a group wanted to purchase one of my premium barrels at the going price and pay me $20 per hour to do the experiment, I might change my mind.  As to the "golden opportunity", I already have that opportunity when I do my five table displays at the major gun shows such as Denver, Los Vegas, and Reno.  Also being accepted into the American Custom Gunmaker's Guild was very golden indeed!  You can also look for an article in one of the Nation' foremost gun magazines this summer.  These are all golden opportunities.  Having said that, I remind everyone that I am semi retired now and not in any kind of mass production.  What I do in my shop is a hobby and not a viable source of income.  But that does not diminish my craftsmanship one iota!             Hugh Toenjes
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northmn

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Re: Barrel Coning and Accuracy
« Reply #48 on: April 10, 2009, 08:25:24 PM »
Thats accuracy, you are hitting what you are shooting at.  To get that accuracy requires precision or the ability to move the sights where you can hit something.  In a machine shop the maching tools have to have an in built precision.  They can machine a doo dad to a certain specification, say within .0004 of an inch.  However, if a customer wants a doo dad 1/4 inch in diameter, the doo dad had better be 1/4 inch in diameter (accuracy).  24.9 inches give or take .0004 may not cut it.  In my lab, they have very expensive weights to check the scales to see taht 5 pounds is five pounds, again accuracy, even though the scales read at .01 of a pound.  PH of liquids is checked to see that the meters are registering what they say they do with a given chemical.  I have a 222 with a scope.  Currently the group is not quite centered on the x ring.  If I move it one click it centers on the other side.  It's obviously not that good a scope but for shooting it works out to say 300 yards depending upon the target.  That is an example of why you may need a precision of say a 7/8 inch group to have the accuracy to say you can keep your shots in a one inch target.  Very fine distinction, but the two really are not the same.  

DP

DP- have you not shot the flybuster Bench Rest target?  That's a target with 6 house flys on it - 5 for a head, 3 for a body and 1 for a wing or leg? The one in the centre of the target is the sighter for checking wind drift.  Put a scope on that old .69 I had and it would get a 5 every time - off the bags - they'd have to give a 5 (or 8? ;D) for the gaping hole where the fly used to be.  That's accuracy - or is that precision?  :-\
« Last Edit: April 10, 2009, 08:27:02 PM by northmn »

northmn

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Re: Barrel Coning and Accuracy
« Reply #49 on: April 10, 2009, 11:47:01 PM »
Another final point on the issue of precision vs accuracy.  The differentiation is made because a rifle and hence its accuracy is a component of precision entities.  If I put a scope on a rifle to test loads and find one that groups 1" and then take it off and sight in with fixed iron sights and get a 3 inch group, the precision of the grouping ability of the rifle hasn't changed just the sights.  A rifle may have its ability to precicely group and its sights the ability to be adjusted by say 1/2 inch clicks at 100 yards (another point of precsion).  It is these component units that permit a level of accuracy.
The precision of a rifle is the same if it groups in the 7 ring or the 10 ring.  that is what Blacksmoke showed with his targets as they had good groups but some were not in the 10 ring.  I beat an individual in pistol once.  He used a 6 o'clock hold to hit the center of a bullseye target, I use dead on hold.  They used a novelty buffalo target.  I scattered my shots in the scoring ring and had all 5 shots in.  He had a beautiful group, better than mine,  high on the target with 2 not scoring.  He was more precise I was more accurate.  Also accuracy is defined as where you sight in those tight groups.  A person that has a hunting rifle sighted in 2 inches high has placed that group accurately where he wanted it.

DP