Best way to break the inside edge of a muzzle

[gizamo]

My muzzle cut on my 20 ga. is sharp on the inside. Starting patched roundball is hard because of it. Is there an easy way to chamfer the inside of the muzzle cut? I just want to break the sharp edge...

 

[Bill Hall]

I like to clean up the sharp edge by using a scotchbrite pad. They come in different grades, but I think the green works well for every application.

Hold the scratchy pad on the floor between your feet (carpet works best), and hold the barrel straight up on the pad and roll the barrel back and forth between your palms, like you're trying to start a fire on the pad with the muzzle. The pad soon conforms to the muzzle profile (you'll see this when you lift the barrel and the pad retains the shape of the muzzle). In a short time you'll have a nice smooth finish without any sharp edges.

This techniques works well on smooth, or rifled barrels, since the back and forth action polishes both sides of the lands equally. Hope this helps, Bill

 

[Zonie]

A very easy way to break the sharp edge on a rifled barrel or a smoothbore is to buy one piece of the black, wet/dry, silicone carbide sandpaper.
Get the 320 or 400 grit.

Tear off a 1" X 1" piece and lay it, abrasive side down against the muzzle.

Place your finger or thumb in the center of the piece and push it down into the bore.

Rotate your hand back and forth while slowly rotating the barrel with the other hand.

Change the paper when it seems to stop cutting. You will be able to feel and hear when that happens.

After a few minutes, all of the sharp edges will be removed leaving a small radius that will not cut or tear patches.

If you don't like the bare metal, polished look this leaves you can use a bit of cold bluing to darken it.

 

[Vaino]

I use a suitably sized ball bearing w/ valve lapping compound for a uniform chamfer....Fred

 

[Bubba45]

Same here Zonie , cept I spit on the wet/dry paper to wet it a bit . :thumbsup:

 

[paulvallandigham]

I have used a small tool( file) handle's back end to support fine emery cloth to take off those sharp edges, and I once use the head of a lag bolt with emery cloth to do the same thing. I use the fine paper, and when I want to finish polishing the surface, I put oil on the abrasive, and that gives a finer polish to the crown.

Oh, to keep the work even, I rotate the barrel in one direction while using the abrasive in the opposite direction. I rotate my hand on the stock so that I complete a full circle with 2 or 3 turns. The more solid the backing of the abrasive, the faster the metal is removed. I have used my thumb, but a wood handle or steel lag bolt works a lot better. :thumbsup:

 

[BrownBear]

Coning for me.

 

[August West]

I use a suitably sized ball bearing w/ valve lapping compound for a uniform chamfer....Fred

I have done this as well and it works very good, I have also used round head slotted machine screw. I chock it into a handheld drill and rotate the barrel as I go, the slot holds the lapping compound well. I have cut and recrowned rifle barrels like this and got excellent accuracy so it must cut an even crown. Chris

 

[roundball]

I like to clean up the sharp edge by using a scotchbrite pad. They come in different grades, but I think the green works well for every application.

Hold the scratchy pad on the floor between your feet (carpet works best), and hold the barrel straight up on the pad and roll the barrel back and forth between your palms, like you're trying to start a fire on the pad with the muzzle. The pad soon conforms to the muzzle profile (you'll see this when you lift the barrel and the pad retains the shape of the muzzle). In a short time you'll have a nice smooth finish without any sharp edges.

This techniques works well on smooth, or rifled barrels, since the back and forth action polishes both sides of the lands equally. Hope this helps, Bill

Sounds like a great idea...probably easier on the aging joints too, thanks!

 

[Vaino]

Perhaps MLers aren't affected as much by an uneven chamfer or crown as CFs, but I still like to have the chamfer as uniform around the dia. as possible. When the projectile exits the bore, the last thing it sees is the chamfer and seeing the gases will take the path of least resistance, will skew the projectile if the chamfer isn't uniform around the entire bore. BP bench shooters use false muzzles to maintain uniformity at the bore. Opinions?....Fred

 

[CoyoteJoe]

If you have trouble starting a patched ball you'll have a very hard time starting a wad. Just get a cone shaped mounted stone from any hardware store. It will self-center and a few revolutions will give the bore a slight bevel or as much as you want.

 

[roundball]

When the projectile exits the bore, the last thing it sees is the chamfer and seeing the gases will take the path of least resistance, will skew the projectile if the chamfer isn't uniform around the entire bore.

I agree...and I learned that first hand by unknowingly creating artificial uneven situations at the muzzle of my .28ga and .20ga smoothbores.

I went through several exhaustive range trips for PRB load development trying to eliminate the occasional 5"-6" flyer out of every 8-10 shots that were otherwise all contained in a 3" aim point sticker at 50 yards.

I finally concluded that when I used an Oxyoke prelubed wool wad over powder...(which are somewhat flexible and have never given that problem in my rifled bores for years)...that the thin wad would apparently curve up around the ball some. And of course that would occur inconsistently so occasionally at muzzle exit I must have been getting blowout at one edge of the wad or another.

Stopped using the flexible Oxyoke wads and immediately stopped getting fliers...started using wads again and immediately started getting occasional flyers. So for my PRB loads in my smoothbores I use small enough balls to allow thick enough lubed patches to withstand the fire without needing the benefit of any OP wad and accuracy is fine, consistent, etc.

 

[Birddog6]

No doubt about it in my mind the Crown is important on anything being propelled out a tube, for the reasons stated.

However, on a ML, I don't think it is as important as on a modern rifle, simply because 95% of the guys shooting ML's will ever reach maximum accuracy from that ML. So if a bad crown is throwing a ball off 1" at 100 yards, most will never know the dif. because he is not capable of shooting the groups or finding the groups the barrel will produce.

A very strict, documented, self disciplined bench shooter may do that, but the general Joe is going to get to a group & say, that will work for Me, and go shooting or hunting & never refine that group to the 1" or less the barrel could produce at 100 yards or so. Thus in this instance, if the gun is shooting to where he wants it, the crown could be a tad off & it have no bearing on it, cause the shooter is where he wants to be with the rifle. And also we have to go to adding the human error on the shooter back in it.

Keith Lisle

 

[Bubba45]

Chuck barrel up in lathe , dial indicate to ensure running true and crown at desired optimum angle for your application .

Or ............get a piece of fine emery paper wet and apply pressure with your thumb , give a few twists to break the sharp edge, then go shoot and have some fun :thumbsup: As long as you dont go nuts with the emery you wont need to do much to deburr muzzle .You can check by dragging finger on edge to see if still sharp.

 

[Birddog6]

That would work ! :hmm: except for the ? 99.9% of the guys that shoot ML's don't have a lathe..........

Keith Lisle

 

[Vaino]

It's so little extra effort to install a uniform chamfer so why tolerate an uneven chamfer? I don't really know how much an uneven chamfer contributes to inaccuracies in BP firearms but even if the amount is small,why even tolerate this situation. Bbl makers are greatly concerned w/ the accuracy of their bbls and taking grit paper and using it w/ the thumb somehow just doesn't make a whole lot of sense, to me anyways. But....there's many opinions on a whole lot of issues....Fred

 

[Birddog6]

I understand what you are saying & a agree the crown being near perfect is a good thing. But in reality, most guys will screw up much more than they will ever fix, cause they "think" they know what they are doing....... I call it monkeyitus others call it allot of things.

IMHO, a lil 400 or 600 grit paper on your thumb used sparingly & just enough to take off that VERY sharp snag that is catching you, and then leave it alone & learn the rifle.......

But lots of opinions on it, mine is just another one.

Keith Lisle

 

[hoochiepapa]

flehto, maybe the crown is not as important to ml's as cf. Take a look at david price's muzzle treatments on his swivel breeches. He files a notch in the land of the rifling as it leaves the barrel, and says it doesn't affect accuracy. Quite an attractive treatment in my book.

 

[tg]

I have a coned shaped drill attatchment for grinding that I wrap some fine emery paper around and twist a few times in the bore with a tap handle, I don't think it takes much unless you want to go the real coning route.

 

[hpbear101]

I have crowned quite few barrel's. I find a screw head that is convex and a little larger than the bore diameter. I use valve lapping paste, put the bolt/screw in a drill, and lap the end of the bore.
Tom