Issues with newly coned barrel

[david58]

Coned my barrel, a .50 Sharon in a Hawken. Took it to the range today - this was my second trip out in the coning process, I polished a bit more yesterday. Based on my first trip out, everything was different from pre-coned - ball size .490 instead of .495, bear grease and tallow lubed patch instead of spit, 80 grain load vs 100 or so.

Accuracy was decent. It has been a long time since I shot 100yards off hand, and got em all on paper. Closer ranges were good on clangers we shot, and won a gong shoot-off.

But...

Patches totally blown through, rather burnt - is that normal on a coned barrel?

When loading, it seems to "catch" at the transition from cone to straight rifling. Cuts my cleaning patches there. I don't really see how that could be using the tool with emery paper, it wasn't a maching job, so should be no step.

Any ideas? I used (misused?) a Joe Wood tool.

 

[Norman Brooks]

Are you spinning the tool to do the coning, if so you may have sharpened the trailing edge of the rifling. You will have to lap the barrel with in and out motions.

 

[Ironoxide]

The patches definitely shouldn't be blown, also the fact your cleaning patches get cut tells me there must be a burr or some sort of "step" there.

If you only had blown patches I would say that perhaps your patch/ball combo is too loose, or the patch material is not robust enough but if cleaning patches get ripped there must be a reason.

Before you try to remedy this it would be useful to learn exactly what the problem is. If you had a bore scope you would've probably already used it. Perhaps you know someone local that could have a look with a bore scope?

Alternatively maybe shining a light and looking through the muzzle you'll see something that looks wrong.

Once you know what the problem is no doubt there will be no shortage of advice here how to deal with it

 

[rafterob]

You switched to a smaller ball and added a fat/oil based lube. You may not have as tight a seal as previous which can lead to blow-by and burning of the patch. First thing to cure is the cutting of the patches and I believe that has been addressed already.

 

[EC121]

Using a big piece of patching material start the ball just past the cone then pull it out and look for the cuts.

 

[Eric Krewson]

A green scotch bright patch and 100 strokes with some oil should correct your problem.

 

[Thomas.bill92]

The first barrel I coned ended up with a rough spot in the bore where the "guide" part of the tool rode in the bore. Turns out, grit and filings were falling off of the tool and getting ground into the rifling by the guide as I used the tool. Still shoots alright but I can feel that spot when loading. Lessons learned.

 

[david58]

A green scotch bright patch and 100 strokes with some oil should correct your problem.

That seems to be the least impactful first step. Meaning, I can only screw this up so much with this as a first step. Danged thing shoots so well, this is a bit frustrating of a side effect.

 

[Hatchet-Jack]

Agree with the Scotch Brite method to smooth it out. I use the maroon (fine) SB myself to polish a bore. Another way is to use chrome polish on a patched jag.

 

[MSW]

i'd try the chrome polish thing ... don't use valve lapping compound

 

[david58]

A green scotch bright patch and 100 strokes with some oil should correct your problem.

Just finished cleaning up after trying this - I can no longer feel the transition when I run a cleaning patch down the bore. Looking forward to getting it to the range after this next spate of travel, I think we may have solved the problem!

 

[ord sgt]

Go back to your original patch/ball combination. Just because you smoothed the first little bit of the barrel, that should not change what worked before. I coned a Green Mountain .50 calibre barrel. I still use the same patch/ball as before the work was done. Accuracy is very good with the fresh rifling where the cone stops.

 

[david58]

Go back to your original patch/ball combination. Just because you smoothed the first little bit of the barrel, that should not change what worked before. I coned a Green Mountain .50 calibre barrel. I still use the same patch/ball as before the work was done. Accuracy is very good with the fresh rifling where the cone stops.

I am liking the .490 ball and lighter charge - less powder, less rump, and it is looking good at 100 yards. Will give it a go next weekend and see how the scotchbrite did.

 

[büchsenmacher64]

A green scotch bright patch and 100 strokes with some oil should correct your problem.

Please explain this process in detail. I just coned my barrel and it sounds brilliant. Thanks

 

[Flintandsteel]

Let’s see, smaller ball, thinner patch, different lube, =blown patch.

 

[Flintlock Whiskey]

The first barrel I coned ended up with a rough spot in the bore where the "guide" part of the tool rode in the bore. Turns out, grit and filings were falling off of the tool and getting ground into the rifling by the guide as I used the tool. Still shoots alright but I can feel that spot when loading. Lessons learned.

I coned a "beater" plains rifle I've had for 40 yrs and found the same thing with the guide part of the tool. It may sound crazy, but I was thinking of hanging the next rifle upside down to grind in the cone. It would be a monumental p.i.t.a. to do, but I don't want to chance it with a better gun. Your thoughts anyone?

 

[Flint62Smoothie]

FYI, before coning I place a cotton ball in the bore just below where the jag guide will be. I also remove the tool & swipe/clean the bore above the cotton ball. Then apply a good lube oil to the jag guide before any use.

 

[hanshi]

Patches totally blown through, rather burnt - is that normal on a coned barrel?

When loading, it seems to "catch" at the transition from cone to straight rifling. Cuts my cleaning patches there. I don't really see how that could be using the tool with emery paper, it wasn't a maching job, so should be no step.

Any ideas? I used (misused?) a Joe Wood tool.

The nature of your rifle's problem is the main reason I prefer polishing the crown to coning.

 

[Flintandsteel]

Why would you cone a barrel, and then use a smaller ball/thinner patch. The whole idea of a cone is to easily use a tighter patch and ball combo.
Blown patch means loose load.

 

[Nazgul58]

I coned one barrel with this type of tool and found the rough spot mentioned. Had to polish it out. I turned the guide portion down to take a tight fit with a patch. Now it turns in the patch not on the bore. Lube the patch well.

My $.02.

Don