Polishing A New Bore

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Greetings

Do folks like to polish newly machined bores by simply shooting them in? Or is there another process to smooth machining marks down.

Pete Davis in Virginia
 

Flintandsteel

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IMG_0402.JPG A decent barrel should not need to be polished. Maybe an old one, but not a new one. Just can't see telling a client that you have to fire a couple of hundred rounds before a barrel will shoot well.
A new barrel,should be ready to shoot as new, or it gets sent back.
First 7 shots it of a new Rice barrel.
 

Erwan

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If you're really worried about that, do it with a very little bit of JB paste from Brownell's or other, but if a piece of hydrophilic cotton doesn't leave any threads in the stripes the barrel is good (with a real new barrel I mean)...
 

Griz44Mag

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View attachment 18799 A decent barrel should not need to be polished. Maybe an old one, but not a new one. Just can't see telling a client that you have to fire a couple of hundred rounds before a barrel will shoot well.
A new barrel,should be ready to shoot as new, or it gets sent back.
First 7 shots it of a new Rice barrel.
With a quality barrel like a new Rice - I would certainly expect it to shoot well right out of the gate...
With high count production barrels, probably not so much, gonna need breaking in.
Even the high end PRS barrel I bought from Lilja came with a recommended first shots clean and shoot recommendation.
Mind you, it shot .5 MOA from the first shot, but still came with a break in routine recommendation to keep it that way.
Not everyone is fortunate enough or has deep enough pockets to buy top end equipment on the first round.
My Great plains (Lyman) took some time and several trips to get settled down. That is a good example of a high production barrel, they simply can't do a high polish and make ready on the barrels at the price point they sell them at.
 

longcruise

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It depends a lot on the barrel and how it was made. Rice, for example, cuts rifling and finishes with a carbide button. You can see the results above.

TC button rifled their barrels and they were pretty much ready to go when they left the factory.

The GPR barrels are not well finished and benefit from a polishing process. So do the Spanish barrels.

To each their own, but I prefer my first 200 to 300 shots to be as good as a barrel can do. It's still fun. So, if a barrel interior finish can be improved then it gets polished.
 
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Greetings

Do folks like to polish newly machined bores by simply shooting them in? Or is there another process to smooth machining marks down.

Pete Davis in Virginia
Some "swab" the bore with a tight-fitting patch and valve grinding compound, polishes and smoothes out the metal. Must be done with care, not over-doing it. Maybe someone else can comment on this.
 

Britsmoothy

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A new barrel can be tough on cloth patches for round balls. Conical shooters won't notice but a patched ball barrel will only gain from some lapping and nothing will be lost.
 

Zonie

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I don't "polish" the bores on new barrels but I do run a cleaning jag with #00 or #000 steel wool wrapped around it up and down the bore a number of times if the barrel has square cut rifling grooves in it.

The button rifled barrels are better than the barrels that were rifled with a cutter but both of them can have sharp edges where the grooves meet the bore. Getting rid of those sharp edges is the reason for my using the steel wool.

The steel wool isn't any harder than the barrel steel but it does a nice job of "dulling" up those edges.
Once this is done, the rifling won't cut the patch on a patched ball so the job is, in my opinion, complete.
 

Phil Coffins

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A light rubbing with JB or even steel wool may be of value for lesser barrel. Don't think of that as polishing a bore. To remove machine marks requires lapping. This is done with a lead lap and takes special tools and a bit of knowledge, it's not rocket science and any one could do it with guidance. Here's some of the things needed and the laps after use. They can't be reused as is but are remelted for the next bore. The breech is removed and a guide is screwed in it's place to guide the rod. The whole process takes hours and yields a bore that is very coincident. Perhaps this will be of value for the discussion.
IMG_0459 by Oliver Sudden, on Flickr
 

SDSmlf

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I don’t necessarily do what you would call polishing the bore, but I do pay attention to the muzzle crown. I use a series of ball bearings, from about one and half times the bore diameter, to right around bore diameter, and wet sandpaper from 240 up to 1000 grit. A couple of turns of muzzle over each ball bearing with progressively finer sandpaper over them gives a smooth barrel crown. Others just take the sandpaper and use their thumb to smooth crown.

As far as bores go, nothing wrong with a few passes of 0000 steel wool or something like JB’s paste to eliminate what I have always called rag catcher burrs, especially with cut rifling. Rice for example uses a carbide bore sizing die to polish and knock down any burrs, but many barrel makers don’t have any post rifling cutting cleanup process or procedure. Any time you cut steel there are going to be burrs. Size and location depends on your process.

Spoke with Don Getz (Getz Barrel) years ago and he recommended using the green (600 grit) Scotch-Brite for smoothing up barrels that were cutting patches. Said it wouldn’t hurt the barrel.
 

30coupe

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Spoke with Don Getz (Getz Barrel) years ago and he recommended using the green (600 grit) Scotch-Brite for smoothing up barrels that were cutting patches. Said it wouldn’t hurt the barrel.
Mike Belleview (sp?) mentioned doing this to his GPR in one of his youtube videos. It seemed to help in that instance. I'd also bet that if Don Getz recommended it, one would be safe to give it a try.

I do agree, though, that the shooting it until it's smooth is more fun. ;)
 

hanshi

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Some barrels, Rice is a fine example, are already smooth as a baby's hiney. If any roughness is encountered in a barrel, A day or more of shooting can take care of that. A quick way to knock down any sharp edges or burrs is to swab the bore with either J&B, ScotchBright or 0000steel wool. doesn't take much. And I second the muzzle crown smoothing advice.
 
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With a quality barrel like a new Rice - I would certainly expect it to shoot well right out of the gate...
With high count production barrels, probably not so much, gonna need breaking in.
Even the high end PRS barrel I bought from Lilja came with a recommended first shots clean and shoot recommendation.
Mind you, it shot .5 MOA from the first shot, but still came with a break in routine recommendation to keep it that way.
Not everyone is fortunate enough or has deep enough pockets to buy top end equipment on the first round.
My Great plains (Lyman) took some time and several trips to get settled down. That is a good example of a high production barrel, they simply can't do a high polish and make ready on the barrels at the price point they sell them at.
My GPR Lyman .54 Perc. had very sharp rifling edges. I used valve grinding compound and a tight patch/was to smooth out.
 
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Mike Belleview (sp?) mentioned doing this to his GPR in one of his youtube videos. It seemed to help in that instance. I'd also bet that if Don Getz recommended it, one would be safe to give it a try.

I do agree, though, that the shooting it until it's smooth is more fun. ;)
The Scotch Brite thing sounds good. Never would have thought of that. Thanks.
 

Britsmoothy

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Never ceases to amaze me how some proportion a measure of god like status to their barrels as if they were possessed by the spirit of rifling and any messing with said spirit will invite doom and despair not only on them but the second and third generation too! Lol.
 
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Never ceases to amaze me how some proportion a measure of god like status to their barrels as if they were possessed by the spirit of rifling and any messing with said spirit will invite doom and despair not only on them but the second and third generation too! Lol.
Ha! Very good! Best regards!
 

sawyer04

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My grandfather refreshed a barrel that was on an old barn gun. He melted lead around a steel rod in the barrel with a wooden stop, removed the lead that actually shrinks when it is cooled and the wood stopper. Put valve grinding compound on the lead slug and ran down the barrel several times. Had to increase patch size, but the old rifle shoots fairly well. It is a wall hanger, but I wouldn't be afraid of it.
 
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