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Author Topic: Bore Lapping  (Read 112 times)

Online Winter Hawk

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Bore Lapping
« on: January 08, 2021, 12:01:14 PM »
From Uncle Russ:

FWIW:  I don't like the sound of that, "It tends to hang up about midway down".......
I have had guns where the PRB was hard as the devil start. and I have had guns where the PRB seemed to want to stop just before seating on the powder charge according to the witness mark on the Ram Rod..... and we all know that ain't good. In both cases, it was fairly easily resolved by the Fire Lapping of 10 / 15 shots.

Don't get excited about "Fire Lapping", there ain't no big deal about doing it and the metal used in the manufacture of today's guns is almost bulletproof, pardon the pun.

Anyway, you have a couple of choices in how you'll be doing this.

You will need JB Bore Paste, and a small tube of Valve grinding Compound. You can "Lap" with JB Bore Paste, or use plain old Valve grinding Compound, but actual Fire Lapping is my personal choice. With Fire Lapping, You load your normal load of powder, I think you said you're using about 60gr FFg, then you make a paste with Valve Grinding Compound and Baby Oil and smear up a .010 patch real good, then you seat the ball and patch down on the powder, Put a cap on it and fire it off, you don't have to shoot at anything in particular, just shoot it! Wipe between shots as necessary and Repeat this for about 10 or so shots, and you will find, or better yet, you should "feel" it loading easier, and much much smoother.

When you've reached this point, after "Fire Lapping" you're not done yet, you then you take a one caliber smaller brass bore brush, in your case a .58 brass brush would be about right, you wrap the Brass Brush good and tight with 0000 Steel Wool to where you can just get it down the bore, then use your fingers to mash/imbed/saturate the steel wool with as much JB Bore Paste as possible, and start swabbing, and you keep on swabbing, and refreshing the JB Bore Cleaner.  You will need 100 strokes minimum, with 200 strokes being the preferred goal.....you want that bore "shiny as a new Nickle", and smooth as a Baby's behind!...all the way down.

Clover Brand Valve Grinding Compound from NAPA is about 280/300 Grit.
JB Bore Paste is about 1,000/1,200 Grit.

Just make sure you use the JB Last.....or, as many have done when they are afraid of damaging the bore somehow, just use the JB and spend the many hours of pushing and pulling on that Ram Rod necessary to get the job done....if you don't care for Fire Lapping that's fine, many don't. Just be prepared for a lot of work if you choose to do it all by hand. It can be done, as it has been done for years.

Just don't believe those old wives' tales about how fragile the barrel of your gun is. Today's technology provides us with the best barrels ever made. Period! You ain't going to hurt your barrel by Fire Lapping!

Years ago, we did this same thing with Bon Ami Scrubbing Powder. An old wives' tale has us afraid to use any other cleaner because we would do dreadful things to the bore of our guns! Well, let me tell ya....my older guns survived Ajax, Bon Ami, and every other scrubbing agent back in the 60's and 70's....some of the guns we got back then from Dixie Gun Works, Log Cabin, Pecatonica River Guns, TOTW, just about all of 'em needed "something" to clean the mess out the barrels left behind by quality control if they even had a quality control back then....and some of the more knowledgeable amongst the shooters of that time came up with what I just gave you....it works.

BTW: We're 3 days into the year 2021, let's make this the year that we rid ourselves of all the old wive's tales that otherwise simply refuse to die.


Russ..
NMLRA Life
"All you need for happiness is a good gun, a good horse and a good wife." - D. Boone
USN June 1962-Nov. 65, USS Philip, DD-498


Posts starting 6/20/20 - 1103
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Online Winter Hawk

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Re: Bore Lapping
« Reply #1 on: January 08, 2021, 12:05:17 PM »
Posted by Idaholewis and RobD:

Excerpt from “Breaking In a Barrel” by Lee Shaver (muzzle and breech loader gunsmith extraordinaire) :

Several years ago, I developed a process for breaking-in barrels for lead bullet use that eliminated the afternoon of shooting and cleaning with jacketed bullet.  It began because I would occasionally have to get bad leading out of a barrel for a customer, and when you charge what a gunsmith must charge to stay in business you don’t want to spend an afternoon scrubbing the lead out of a customer’s gun.  And I’m sure the customer would rather not pay for said services.

What I learned was that when scrubbing lead out of a barrel, I could run a tight oily patch through a few times and then take the patch off the jag.  I would then unroll a little 0000 steel wool and cut a piece the size of the patch.  Place that over the patch and then run it all through together.  (The proper fit is when you have to bump the rod a few times with the palm of your hand to get it started in the bore.)  When you shove that steel wool over a patch through the bore of a badly leaded barrel, it may sound like paper tearing as the lead is ripped out of the barrel in a pass or two.  I can clean the lead out of the worst barrel in about ten or fifteen minutes that way, and an average leaded barrel will be clean in a few strokes.

After using this technique for a while, I began to notice that the rifles that I was de-leading that way seemed to lead less afterwards, which got me to thinking.  We use fine steel wool on the outside of old guns all the time to do some cleaning or spot rust removal, and it does not damage the surface of the steel.  It just scrubs it.  Which lead me to consider the fact that we are trying to break in a barrel by smoothing the surface without cutting, and it seems to me that process would go much quicker if we used something on the inside of the bore that was closer to the hardness of the barrel instead of lead or copper.  So I started trying the steel wool and oiled patch technique on new barrels before shooting them.  I use it about as tight as I can get in the bore and wear out a steel wool pad or two in about 15 minutes, then I go and shoot the rifle.

How well does it work you might ask?  On a few occasions, I have built a new rifle and taken it to a match without ever having fired the rifle.  All have performed flawlessly in their first match and several times I won the match or set a record with them.  On one occasion, I set a new 300 yard range record with the first 13 shots out of a barrel.  This method has become a service we offer to our customers here in the shop and I have shared the technique many times with others.
NMLRA Life
"All you need for happiness is a good gun, a good horse and a good wife." - D. Boone
USN June 1962-Nov. 65, USS Philip, DD-498


Posts starting 6/20/20 - 1103
Posts ending  9/20/20 - (?)