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Login Name Post: Smoothing the crown        (Topic#240255)
armakiller 
70 Cal.
Posts: 4111
armakiller
11-16-09 02:51 PM - Post#783108    


Well folks just let me say that ya'll take care when hitting the crown of your barrel with the emory cloth to smooth out the crown of your rifle.I did as sugjested to help with loading a tighter patch and messed up.I could load the tighter patch but i could not hit a paper plate at 50 yrds,went back to my original load 1 1/2 to 2 inch groups with this[.495rb .15 patch 70grns of 3f swiss]same thing,all over the target.So i started all over.Now it shoots 80 grns 2f swiss with a .490rb with a .18 patch.2 inch group at 70yrds. Any charge of 3f .490rb .18 patch was all over the target.This is with a flintlock rifle with a GM barrel.

 
paulvallandigham 
Passed On
Posts: 17538
paulvallandigham
11-16-09 11:46 PM - Post#783317    

    In response to armakiller

If you are going to change from a .495 ball to a .490 ball, then you have to change from a .015" patch, to at least a .020" patch to get the same performance. Using a .018" patch will allow gas blow by, and cutting of the ball, after the patch is burned and torn.

Remember the basics of what you are trying to achieve: you want to seal the gases behind that Patch and ball. To do so, you have to use a ball that is correct for the bore diameter, AND the patch thickness you need to fill the grooves.

If you still are willing to take advice try this: Get some .500 size OP wads from Track of the wolf( actually, they come in at .510") Us them over the powder charge. They will act as both a fire wall, to protect your patch from burning,and will get down into the grooves to provide a good gas seal. They do in my .50 GM barrel. Once you seal those gases behind the PRB, you can vary components there and still get reasonable accuracy.

 
Trench 
62 Cal.
Posts: 2989
Trench
11-17-09 12:37 AM - Post#783331    

    In response to armakiller


Well, here's a way to look at it. It may have seemed minor, but you changed something when you used that emory cloth. What the rifle liked before the emory cloth may not be the same after the emory cloth...or any other type of permanent change.

I'm glad you found a new load combination for it. That must have been frustrating.

 
J.D. 
69 Cal.
Posts: 3196
11-17-09 12:44 AM - Post#783334    

    In response to armakiller

I have done all of my rifles this way, and haven't experienced any negative change in accuracy.

If the crown is not concentric, the balls should still group, but at a different POI than before. Again, I have never experienced any negative change in accuracy or POI.

Quite frankly, I don't quite know what would make a barrel loose accuracy like that.

What grits did you use. How aggressively was it used, and how much material was removed?

What do the fired patches look like?
God bless

 
Billnpatti 
Cannon
Posts: 7229
Billnpatti
11-17-09 06:10 AM - Post#783357    

    In response to armakiller

If you tried using emery paper on your crown without a proper tool to guide it, that was your mistake. What you need is a proper tool to do the job. I bought one of these and coned all of my muzzles with no decrease in accuracy. I cannot say that I got any increase in accuracy either. I'd say that there was no change at all in accuracy but it was so much easier to load a patched round ball. Take a look at this article and if you are interested, order one out and use it to correct your muzzle. In my honest opinion, I think you will be quite happy that you did.

http://http://www.muzzleloadingforum.com/fusionbb/forum/index.php?topic=4330.0

Edited by Billnpatti on 11-17-09 06:12 AM. Reason for edit: correct typo

 
David Box 
40 Cal.
Posts: 137
11-17-09 09:50 AM - Post#783425    

    In response to armakiller

The crown needs to be super smooth to give you the best accuracy. Here's how I finish out the crown on all barrels, high power, pistol, muzzleloader, it doesn't matter. Go to the hardware store and buy a few brass round headed screws. You want one that the head will almost but not quite fit down the barrel. Also go by CauQuest or NAPA and pick up some valve grinding compound. It comes in two small cans. One will be course and the other fine. They come together and only cost a few dollars. Chuck the screw into a hand drill by the threads and dip the head in the course compound. Place the head on the crown and while applying a little pressure run the dril slowly for several seconds. When it seems to smooth out, repeat with the fine compound. I have crowned cut barrels on rifles, shotguns and pistols and re-crowned beat up barrels and it just about always improves the accuracy.

 
J.D. 
69 Cal.
Posts: 3196
11-17-09 11:38 AM - Post#783466    

    In response to armakiller

Just a thought, you may have raised a burr on the lands. Try scrubbing the bore with a piece of green scrubbie on a smaller jag, giving special attention to the area that was smoothed. Steel wool might work too.

God bless

Edited by J.D. on 11-17-09 11:40 AM. Reason for edit: caint spel

 
Zonie 
Moderator
Posts: 25659
Zonie
11-17-09 07:58 PM - Post#783647    

    In response to J.D.

I've used silicon carbide (wet/dry black colored) sandpaper many times to finish the crowning on cut off barrels and to smooth out the existing crowns on factory barrels.

This is a picture of the final finish


Just Jim...



 
armakiller 
70 Cal.
Posts: 4111
armakiller
11-20-09 06:01 PM - Post#784825    

    In response to Zonie

Hi folks ,to answer some questions the grit was 320 and i was not very agressive at all and hardly any metal was removed just enough to allow a.495rb with a .18 patch which i was'nt able to load before.After the first range session i hit the crown with some 0000 steel wool because the first thought was i had a burr somewhere.Nothing worked. My patches are in very good shape no cuts or burns just frayed a little around the edges.TOTW mink oil for lube.btw i think 1 1/2 to 2 inch groups at 70 yards would be hard to improve on.I don't shoot competition,just go hunting max range is 75 to 80yrds cause i can't see good enough to shoot any farther,and shoot at the range every now and then to keep the flinches away.The most important thing is at least i did'nt have to have the barrel recrowned.With the group i shoot now i don't think i'm getting anywhere close to the crown with any abrasive at all.Just prb.

Edited by armakiller on 11-20-09 06:30 PM. Reason for edit: No reason given.

 
paulvallandigham 
Passed On
Posts: 17538
paulvallandigham
11-21-09 12:34 AM - Post#784949    

    In response to armakiller

The frayed edges are normal. It occurs when the patch hits the wind/air at the muzzle as the ball separates from the cloth patch. Its like cracking a whip frays the end of a rope, or leather whip.

You want a spent patch that has NO hole, or cuts, or slices, No burns, only some black or brown charring where the grooves held the fabric. Too much charring or black color at the grooves indicates the fabric is NOT thick enough to fill the grooves. Too hard to push down the barrel indicates the fabric is too thick. If you are using the right AMOUNT of lube, the center of a used patch will be off-white, because the lube will be pulled to the sides and edges of the patch as the ball moves up and out the barrel. Th lube bleeds off the fabric onto the walls of the barrel( lands and grooves.)

If the center of the patch is burned, the powder you are using is either burning at too hot a temperature, or you don't have enough lube on the patch, or the wrong lube, or you have a very heavy load of powder behind the PRB.

This is the kind of problem where the " fun" begins, figuring out how to fix it for a particular gun.

 
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