[zachaliles]

and ive done quite alot of it hanging around here. lots of great info. so what im asking this time is how you go about slugging a barrel. i know the reason behind it, i just dont know the method. please school me on this.

 

[kdub]

If you can still find them, or have some, a lead bell sinker that's oversize for the bore work well. Cut the brass wire off, put the tapered end in the greased bore's muzzle, drive the weight into the bore, trim the excess that flattens out around the muzzle, and using a wooden or brass starter, drive the weight down the bore. Once it is engraved it will be easier to push. You can now use a flat nosed cleaning jag on a cleaning rod to push it to the receiver.
Not having the fishing sinker, a soft lead bullet will work as well. Try to find one that is oversize to the bore, but not overly so. The bigger the harder to get it started.
On recovery of the lead slug, measure the greatest dimension. That's the groove diameter (which we use here in the U.S.) and it will tell you the bore size.

 

[Rubberduck]

Some of us dont know the real reason behind slugging. Iv personally heard of it but have no idea what it does and why. Please elaborate

 

[mattsbox99]

Its used to show any constriction in the bore, constriction will increase fouling and decrease accuracy. Often times if a barrel is stamped with anything it can cause a constriction, such as warning marks or even caliber stampings. Very thick barrels won't usually have any constriction and featherweight barrels are more affected.

 

[Kragman71]

Slugging the barrel also provides bullet that you can measure with a micrometer caliper to determine the minimum size of the bore.
If you have a constriction in the bore,that point will determine the diameter of your slug.
Lapping the bore will remove the constriction
Frank

 

[zachaliles]

thats how i thought you would go about doing it. thank you.

 

[osprey572ci]

another day...another lesson. Gotta love this forum.

 

[wolfen]

I guess its time for another lesson. What is Lapping? And how do you do it?

 

[zachaliles]

its a way of using abrasives to take out tool marks or irregularities in the metal finish.

 

[osprey572ci]

They sell some fire lapping kits on this site that seem very user friendly. It's a way to remove factory machining marks from your barrel which in turn reduces lead and copper build-up?? There are others here that may correct me and for sure give you a more detailed explanation. They will probably refer you to another thread that has already covered this.

 

[spitfire_er]

They sell some fire lapping kits on this site that seem very user friendly. It's a way to remove factory machining marks from your barrel which in turn reduces lead and copper build-up?? There are others here that may correct me and for sure give you a more detailed explanation. They will probably refer you to another thread that has already covered this.

In a nut shell that's basically it. It smooths out the bore, so if your grooves or rifling that looks like this:

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ = machine marks

After lapping idealy it will look like this:

____.____.____.______._____.____._____.____.___.___ = smoothed out metal

of course this is an exaggeration, but hope it helps.

It can be done by two main methods, Fire lapping which is basically a bullet coated in abrasives to smooth out the bore, and hand lapping. The lead hand lapping method usually involves a steel rod being placed in the bore from the breech end of an unchambered barrel and stopped an inch or two from the muzzle. Then molten lead is poured into the barrel to obtain a cast of the bore. Then a very fine abrasive oil compound is placed on the rod and worked back and forth in the bore until the person doing the lapping feels that he/she has obtained the proper amount of lapping. Then if desired patches with other abrasives may be used to burnish or buff out to a final desired finish. This process usually leaves the best bore you can get on a rifle barrel.

Here is a comparison video done by Lilja Barrels showing the difference between a Remington Factory barrel, and a custom hand lapped barrel. The first time I watched this I failed to notice they were running up and down the barrel while turning on the custom barrel.

http://www.6mmbr.citymaker.com/f/Lilja_BoreScope_VID.wmv

Of course you're not going to turn that Rem barrel into that custom barrel, but you could work with it to make it shoot a little better by lapping.

 

[mattsbox99]

You'd be really surprised by what just a hundred strokes with a bore compund can do.

 

[kdub]

Told my local gunsmith some years ago that I was going to firelap a new barrel. He snorted and said, "can do the same thing shooting 50 rounds or so!" Went ahead with the BTB fire lapping, but often wondered the wisdom of his remarks.

 

[wolfen]

So lapping would create a smoother barrel? So, this in turn I'm assuming would mean faster bullets, more accuracy, and more power?

 

[kdub]

A smoother barrel - yes. Faster bullets? Maybe. It would have less friction and would cause less gilding metal stripping, so that would make it "faster". As far as power, that is less assured. When folks went to moly-coating of bullets and bores, the slicker, less friction results caused a drop in velocity, hence power. Theory has it the bullet didn't hang up in the bore as long so powder gasses could develop full potential pressure. All I know is when I molycoated, I had to add more propellant to get back up to velocity levels of plain jacketed bullets.

The biggest thing about a lapped bore is the far greater ease in cleaning. Takes less than half as long, usually.

 

[wolfen]

So, if it only makes cleaning guns easier, then what's the point? Unless it helps with accuracy and terminal velocity why do it? Not to sound negative, it just seems like a waste of time that could be spent shooting or hunting.

 

[zachaliles]

well, if youre wasting less time cleaning then youre technically wasting less time overall, right? i personally hate cleaning my rifles. thats why i dont clean my .223 anymore, other than the chamber and bolt face. barrel stays dirty and accuracy hasnt dropped off at all. some days it seems better.

 

[jeffro]

Wolfen

I honestly believe that firelapping increases accuracy. If you take a borescope and look at a factory barrel versus a custom barrel by a good company, you will see a difference between what the lands and grooves look like. In a custom barrel the lands and grooves are much more uniform and squared off lands. The factory barrel will have some small (or sometimes large) defects. The firelapping should take care of some of the defects and make the barrel more uniform.

I think that it should also help in taking off less guilding metal like kdub said and therefore there should be less copper fouling which makes the job of cleaning easier.

But thats just my opinion