Coning a barrel

[zimmerstutzen]

For those with a choked bore at the Muzzle a cone muzzle WILL ruin all semblance of accuracy. My best rifle barrel was an h&h with a choke at the muzzle. With proper sights it would shoot one hole at 100 yds from the bench. Coning would have opened that to a 5 shot cloverleaf.

 

[Vaino]

In spite of the fact that "coning a muzzle" mught not be HC, my Hawken elk rifle will be coned because of easier loading w/ a tight fitting PRB.

IT will be coned w/ a Woods coning tool that uses various grades of grit paper...definitely not w/ a reamer which can cause chatter marks because of the intermitent rifling.

Why a tight fitting PRB combination? Just don't like "blowby" through the grooves w/ a loose fitting patch. Don't know if the my tight PRB combo completely eliminates the "blowby, but it surely would minimize it.....Fred

 

[Artificer]

To Fred and everyone,

My post above was aimed at the historic period and was not meant to be for or against muzzle coning today. I mentioned a reamer and pilot in the previous post, because they did make reamers and other cutting tools by hand filing cutting edges/flutes into Iron and/or Steel.

I deliberately did not mention a tool that would be like the modern coning tools that use Emory Cloth instead of cutting flutes. The closest thing they had to Emory Cloth was what they called “Glass Paper.” Glass Paper was made by crushing glass into powder and gluing it on linen paper, so while it was “sorta/kinda” close to modern Emory Cloth, it was a very different animal. However, using Glass Paper was also something that cannot be documented on early guns outside a small number of very expensive guns that were sent to period “Varnishers” for a very high gloss finish on the wood. Those guns would have been the kind primarily made for the Nobility and Royal Customers, though an extremely rich person (and not of those Social Classes) may have owned such a gun.

Gus

 

[Scota4570]

I'd prefer to do this in a lathe. What is the taper, in degrees, that works best.

 

[BrownBear]

For those with a choked bore at the Muzzle a cone muzzle WILL ruin all semblance of accuracy.

I suppose it depends on how (and where) the bore is "choked." While I might refer to the bore on my GRRW 58 caliber Hawken as choked, in fact it's a long taper from breech to muzzle, and I sincerely doubt coning would affect accuracy much.

Having said that, even though I've coned several other bores, I haven't and won't cone the GRRW. I've worked around the challenges of loading it, so I simply don't need to cone it for happy use.

To illuminate that decision, consider this. The taper is so great that a bare .575 rests in the crown without dropping. If there's the slightest irregularity on a bare .570 ball it hangs too. I've had to drop to a .562 ball with .018 ticking patches for loading. Still a little starchy to get moving, but once it's in, the ball moves with not much more than the weight of the ramrod. The last half of the way down, it literally free-falls down to the powder under the weight of the ramrod.

Sounds like the formula for disastrous accuracy problems? Think again. It's certainly the most accurate of any muzzleloader I own, and I've never seen any one else's shoot better.

Got the loading issues sorted out to my satisfaction, so no need to cone. But I don't fear any loss of accuracy if I did cone.

 

[jerrywh]

This is just random info. Not in response to anybody in particular. Related to the subject at hand.
http://www.flintriflesmith.com/WritingandResearch/Research/sandpaper.htm

 

[MSW]

that's really cool! thanks for the post!

 

[ZUG]

I use to "cone" the muzzle deeply but found that it was not necessary and got better accuracy with a nice small taper and radius at the muzzle. This is what I do: I have a lathe but you can use a varible speed hand drill, chuck a tapered stone in the chuck and remove the lands to the grove diameter for only about 3/8" to 1/2" depending on caliber, then polish it by placing a 320 grit emery cloth between the stone and muzzle, polish till the stone scratches have been removed then go to 400 grit then 500 grit and that should do it - have a look

 

[M. De Land]

I use my lathe to crown all barrels as well and the reason I don't like to cone them with a lathe is because the bore is seldom perfectly concentric. I feel deep coning can be more perfectly done with a hand tool and very snug fitting pilot.
I also don't like to use sand paper down in the bore as it tends to radius the land width near the end as show in the picture. See how they are radius-ed in the width at the muzzle. This lets gas escape around the patch just before it clears the muzzle and tends to fray and burn holes in them at the land corners.
In my opinion this is great for seating the ball and patch but not so great at ball exit.
My guess is that retrieved patches will show fraying or holes burned through the patch at the land corners.
I suppose if it does the same all the way around, all the time than consistency would be maintained but when the muzzle begins to wear from rod wear it will probably become a problem.
If your going to lap out the scratches then turn a tapered spud of brass to the same taper as the reamer used and roll in some abrasive grit. This will maintain the profile cut with the reamer and not round off the land end width.
There should be no change in the land width profile when coning.
Same deal when chambering a barrel with a reamer.

 

[M. De Land]

I would use the lathe for deep hole coning if the reamer were compatible for use with a floating reamer chuck which will float to the center of bore concentricity.

 

[ZUG]

I see we have a difference of opinion on this -- no problem - you do it your way and I will do it my way :v . I have not had any "burn-through" with this method and accuracy has not diminished :thumbsup: . I've had more accuracy lose with the "deep hole" coning method -- as I said do what works for you :wink: .

 

[M. De Land]

I agree, after all, difference of opinion is what makes a horse race and wouldn't the world be boring if we all thought the same thing. :wink:
A point of interest is that I have seen firelapping to the same thing to lands in the breech end of a revolver barrel just after the cone. Course were not dealing with a patch in a revolver.

 

[ZUG]

YUP -- that's what makes the world go around. By the way those two barrels have radius bottom rifling so the crown might look different to most.

 

[Scota4570]

To do any crowning or chambering work a lathe is best. The other ways are work arounds for not having a lathe and knowing how to use it.

You must use a 4-jaw and a spider. Make a spud that is push fit in the bore. Indicate off that. It does not matter if the bore in centered, concentric and parallel to the outside. Most aren't actually. Once your spud is centered and not loping your cuts will be true.

 

[ZUG]

Thanks for the input but this is common knowledge - did you notice the dial indicator in the picture -- it is for indicating the spud the goes into the bore to center the barrel (using a four jaw chuck because the barrel has 8 sides) -- thanks again. :thumbsup:

 

[M. De Land]

Yeah,that's fine if your lathe has spindle hole enough to get a barrel through and you can use a single axis spider but my lathe does not so I'm forced to use a head stock center, lever plate and two axis spider off the tail stock.
As you probably know a two axis spider is a real pain in the keester to get coaxial with the bore off the tail stock.
Bores are almost never perfectly straight anyway let alone parallel to the exterior,most look like a jump rope when viewed down at a slow RPM.
If they can be deep hole bored to with in .003 runout in 30 inches, they are about as straight as they come and I'd wager most have far more runout than that on a production barrel.
Now one see's the advantage to using a floating reamer tool when cutting chambers.
Bores are not only tangentially off co-axis they are often spiral curved as well.
Bore spud will get you close but even they by nature of being slip fit do not produce "dead nuts" center any more than a columnator spud will.

 

[hanshi]

Actually a good "smoothing" of the crown that goes into the rifling just enough to "break" the edges on the lands and offer an easier starting of the ball can be done with emory cloth and one's God given thumb. One will still need a short starter but the prb goes in with no tearing of the patch and the transition from starter to seating is smoother. I use tight combos and don't need coning or undersized balls. A tight combo and the right lube keeps the fouling down to just one shots worth.

 

[Gustavo Hoefs]

Could you please post pics of your targets after you have the rifle shooting the way you like ?

 

[Artificer]

Actually a good "smoothing" of the crown that goes into the rifling just enough to "break" the edges on the lands and offer an easier starting of the ball can be done with emory cloth and one's God given thumb. One will still need a short starter but the prb goes in with no tearing of the patch and the transition from starter to seating is smoother. I use tight combos and don't need coning or undersized balls. A tight combo and the right lube keeps the fouling down to just one shots worth.

Well, there is a possibility of a problem doing that IF you just filed the face of the muzzle perpendicular to the bore. That procedure would most likely leave sharp edges/burrs on the grooves near the muzzle. Not really a problem on most modern barrels when you receive them from the maker as they are usually chamfered a bit already, though.

I have a 12 flute, carbide, hand chamfering/bore crowning tool I use to get a very clean and precise chamfer on the end of a barrel. Just have to have different pilots to use in different bores. However, this is only a chamfering tool and not a "muzzle coning tool."

Gus