fire lapping bore?

[Bret4207]

You won't hurt a barrel firing several hundred condom loads before you start accuracy work with cast. But, you can look forward to some boring, hours long cleaning sessions trying to get all the jacket fouling out. Also, if it's a real burner, like a 22-250 that you want ot use for cast, the hot loads tend to errorode the throat and roughen it. It may matter, it may not. I've hand lapped a lot of barrels and I think fire lapping is just as good or better except in weird circumstances where you want to hit one spot and you know exactly where it is. A rust spot for example. Otherwise both methods get you to more or less the same place given due care and knowledge.

[Bucks Owin]

HI,
I have heard, not sure it is true, that most rifles/pistols shoot smaller gruops afer 1-200 rounds of j-bullets.
Is this , in a sense a form of fire lapping?
I have been told these 1st 1-200 rounds basicly remove birrs & imperfections.
If this is true why not just shoot & have fun.

I bought a 46 yr old Ruger .44 that was so copper fouled from cleaning neglect that it took me a couple hours to get the bore clean again. At that point I could plainly see (without magnification) machining marks both linear and radial and the bore had a tendency to lead with CBs. Another hour of polishing with JB bore paste knocked the rough edge off the machine marks. Even though they are still plainly visible, the gun no longer leads at the drop of a hat....

If 46 yrs worth of J boolits didn't smooth those machine marks, I don't see how 200 rds could do it! Maybe it depends how severe the "imperfections" are....

Just my experience,

Dennis

[felix]

Before several years ago, most if not all ruger pistols had barrels made of 4140. It will take abrasive materials to knock off tooling marks, and copper jackets won't do the job. Too much of a difference in materials. But, high antimony, low tin, boolits will smooth that barrel out in time. Actually, longer than you think it should. The newer barrel steels ruger uses are not as hard, but are tougher. Talking especially the 454, 480 guns. ... felix

[Bucks Owin]

Interesting!

Thanks Felix,

Dennis

[klausg]

Bucks- my experience with j-bullets & smoothing a bore, basically ran along the 'break-in' as described in the Barnes manual; IIRC you shoot 30 rounds, 10 singles and 10 doubles; with thorough cleaning between each string. Felix is quite obviously a smart guy, and if he says they were made of harder steel I believe him. But from your description, it also sounds like the former owner never cleaned the copper out and it's difficult for a j-bullet to smooth anything out of the steel when it's riding on a layer of copper. Just another way to look at it, FWIW, I'm going back to my corner now

-Klaus

[felix]

Klaus, sooner or later, high antimony, low tin boolits will take out the copper too. Best to get the gun ready up front for lead like everyone says, by getting rid of the copper and burnishing the barrel first with very high speed condoms. This is so your interest in the gun's accuracy will remain high when it comes time for normal lead boolits. Remember, though, that antimony crystals have very sharp edges like the metalic wool. ... felix

[Bucks Owin]

Bucks- my experience with j-bullets & smoothing a bore, basically ran along the 'break-in' as described in the Barnes manual; IIRC you shoot 30 rounds, 10 singles and 10 doubles; with thorough cleaning between each string. Felix is quite obviously a smart guy, and if he says they were made of harder steel I believe him. But from your description, it also sounds like the former owner never cleaned the copper out and it's difficult for a j-bullet to smooth anything out of the steel when it's riding on a layer of copper. Just another way to look at it, FWIW, I'm going back to my corner now

-Klaus

Well, in my case, the previous owner had LOTS of copper fouling caught up in the rough machine marks and just kept on shooting.....(maybe for 46 years!?!)
Once I got down TO the bore I was able to smooth it up enough with JB.....

That's my story anyway...

Dennis

[JackOfAllTrades]

Before several years ago, most if not all ruger pistols had barrels made of 4140. The newer barrel steels ruger uses are not as hard, but are tougher. Talking especially the 454, 480 guns. ... felix

You confuse me with the 'not harder, but tougher' statement.

-Steve

[felix]

Steve, the term 'tough' means being able to bounce back without PERMANENT deformation. The term 'non-brittle' or 'soft' means being able to REMAIN deformed. The term 'hard' means the RATE of shape change.

It is difficult to QUAntIFY these terms, but it is easy to QUAlIFY them by examples. For example, you want a car bumber to be SOFT and TOUGH. You want frames for eye glasses to be HARD and TOUGH. You want a gun barrel to be harder and tougher than bullets/boolits.

felix