BARREL LAPPING: why ain't it S.O.P.?

[mindcrime]

I used a NECO Fire Lapping Kit to lap my former 300 Win mag A-Bolt barrel and it worked very well. Less copper fouling after 20 or 30 rounds.

Eric B.

I've had AWESOME RESULTS with the Neco kit. It made a fouler of a 300 Win Mag Sendero, a Colt AR (1-9", non Chrome-Lined, JFI), and a warn out 6 PPC barrel [used mostly for fireforming] MUCH easier to clean, and in ALL EXAMPLES, I saw group sizes literally cut in half!!!!!

 

[J E Custom]

I agree with these two quotes since I've had more experience than I care to remember lapping barrels. It IS labor intensive and has to be a large factor in driving up the price of a finished barrel.

It's not just training when teaching a person how to lap barrels. It's a feeling and knowing what can and cannot be done. There is art to such a practice.



This might apply to an existing barrel which has been attached to an action such as one from the factory but it certainly does not apply to custom barrel manufacturers at all. Many custom barrel makers lap their barrel as a matter course, a routine, as part of the manufacturing process and there is no harm done because a professional is doing the lapping. They want their customers to receive the very best product they can manufacture. Pride in workmanship.

Yes you are right about custom barrel makers routinely lapping there barrels I may have not said it clearly but the reference was to pre chambered barrels. And the manufactures do the lapping to barrel blanks that will have the muzzle end shortened by the smith. Some even make a cut in the muzzle end about 3/4 " from the end so it will be remove. This is the time to do the lapping because it can also be air gauged to verify dimensions and quality. If you try to lap a pre chambered barrel there is a good chance you will open up the throat, so it is best done before the chamber is cut. or re chambered to something longer to clean up the throat that has been lapped.

In my opinion, the best time to have lapping and fluting done is at the barrel manufactures so they are responsible for quality.

J E CUSTOM

 

[sable tireur]

In my opinion, the best time to have lapping and fluting done is at the barrel manufactures so they are responsible for quality.

The blank stage is the only time to do everything you want to do to a barrel so that the final form can be realized without compromise.

While air gauging is still done, the world of computers and advanced manufacturing techniques have basically replaced it with vastly improved, sophisticated methodologies which can help determine every tiny detail of the interior of barrels. It is extremely fascinating.

 

[tdot]

The blank stage is the only time to do everything you want to do to a barrel so that the final form can be realized without compromise.

While air gauging is still done, the world of computers and advanced manufacturing techniques have basically replaced it with vastly improved, sophisticated methodologies which can help determine every tiny detail of the interior of barrels. It is extremely fascinating.

Any youtube videos of that process to measure the barrel interior? I'd love to see it.... a quick search didnt turn up anything for me... but I'm probably using poor search terms.

 

[tdot]

Your post has merit, but when I was working retail there were very, very few things in the whole store that could carry a 100% mark-up. None of the firearms would. A really nice margin on a firearm was 30%, and those were rare. Most really retail savvy folks look at this industry and wonder why anyone bothers.

That was just an example for easy math. I'm much better at my 2 times tables then my 1.325.

You think retail is sporty. Try distribution on a National Level.

 

[sable tireur]

No, I doubt it's your choice of search terms. Most of the newer technology is protected by the developers since it's proprietary and is therefore unavailable to the general public until protected. I've only seen it briefly and wasn't allowed to have a phone or camera with me.

 

[Danehunter]

JE is absolutely correct on lapping barrels before chambering them to avoid opening up the throat area. And that's how Bartlein and other custom barrel makers do it.

I'm very curious as to how Miroku does Browning's barrel lapping. Browning says it's a "proprietary" method. Likely patented.

Also throat wear is what worried me about NECO fire lapping. But NECO assured me that loaded ammo rolled in NECO grit would have very little effect on the throat. I still wonder... Barrels wear out at the throat.

Eric B.

 

[J E Custom]

[QUOTE="Litehiker,

Also throat wear is what worried me about NECO fire lapping. But NECO assured me that loaded ammo rolled in NECO grit would have very little effect on the throat. I still wonder... Barrels wear out at the throat.

Eric B.[/QUOTE]

You are right to worry about throat wear with this system. the problem with it is that it wears more off the throat end than it does the muzzle end.

In many cases it can be successfully applied to barrels that are really rough and can use some help, But they do shorten the life of the barrel buy removing some of the throat.

Like everything in this sport, there is no absolute rule and when applied correctly the process can improve the accuracy if only for a short time. I have bore scoped barrels that have used this process and even tried to save a factory barrel and monitored the velocity and the accuracy at different levels of the procedure watching the progress with the bore scope and came to the conclusion that It is a short term fix and saw no advantage in doing it instead of letting bullet do its thing over time evenly.

I have no ax to grind with fire lapping if it is used for a last resort because it does have its place. I would not recommend it on a custom barrel because in my opinion it is detrimental to long term performance.

Let the bullet do the work and avoid any type of abrasive in the bore.

Just my opinion based on my experience.

J E CUSTOM

 

[Danehunter]

One final note on my "complaint" about the general lack of barrel lapping on production rifles.

I would bet that Miroku has developed a way to use CNC machines to do barrel lapping. That would take out human error and the need for skilled labor in the process.
Which brings up the question, is this still a costly process if CNC machines are used to control lapping?

Eric B.

 

[ntsqd]

There is still machine tool & operator time involved, not to mention the programmer's time to program the machine. Then factor in if they had to design and manufacture such a machine because no one makes it for sale. That first barrel was likely Extremely expensive because of all of the time & resources that went into getting to that point.

 

[Mikecr]

I disagree with an implication that taking more out of the throat than the muzzle is a 'problem'. An accurate barrel does not ever have the muzzle end more open than the breech end. So to ensure this never happens, barrels are marked after lapping, and the muzzle end is expected to be cut off during finishing.

This can be one of the reasons(aside from reduced copper fouling) that people have been so happy with results after fire lapping. I say 'can be' because it would depend on the barrel.
What I do know is that Tubb's FinalFinish and TMS bullets provide a surface profile matching the best in lapping, and that I've never seen the process hurt a thing. For rough factory barrels, it has always improved my results.
Having seen this so consistently, I now break-in all barrels, including aftermarket, using FF (10 shots, done).

Barrels touted as consistent in bore/groove, end to end, are usually accurate enough because pressure at the breech end is higher than the muzzle end on firing. This has the muzzle expanding less, leaving it the tightest portion of bullet travel.

This can be taken to another level for additional accuracy gains. An 'accurizing' service once offered by Lothar Walther lapped for a particular taper bore. I suspect it was done using extrude honing with bores beginning slightly under cal. Unfortunately, LW makes a lot of business changes into and away from things, while seemingly having no appetite for glory.

You might not know it but LW is the most capable barrel maker in the world. If you can dream it up, they've probably done it and can do it. Any steel, taper bore, gain twist, etc., any rifling methods, treatments, and any measure to any specification.
They'll do it for you at an appropriate price, with lot orders of 100[min](last I inquired). Very interesting company..
If I were rich, they'd make some money from me.

 

[Frog4aday]

Tubb FinalFinish loaded rounds are about $40 for most conventional calibers (http://www.davidtubb.com/final-finish-loaded-ammo).

Buy factory rifle you desire. Buy the FinalFinish loaded ammo. Go to range. Shoot. Clean. Shoot. Clean. Done. There's your 'lapped' barrel for $50 or less.

You can FEEL the barrel getting smoother and more 'equal' as you clean during the FinalFinish process. I was surprised. The barrel fouls less after treatment. The barrel shot more accurately after treatment. One could just fire a lot of 'regular' bullets and eventually smooth out a barrel, in time, with lots of shooting and cleaning, but the FinalFinish process gets it done in 10 to 20 rounds. I like it. People who are on the fence should try it in one of their "problem" rifles (fouls a lot? poor accuracy?) and see for themselves.

 

[mindcrime]

Also throat wear is what worried me about NECO fire lapping. But NECO assured me that loaded ammo rolled in NECO grit would have very little effect on the throat. I still wonder... Barrels wear out at the throat.

Eric B.

I have used Stoney Point OAL guage (Hornady now owns the design) to check the change in the throat.......it's quite negligible for the 50 rounds that you fire. When I noted a 6 PPC, it should have given you an idea of my PRECISION.

 

[Danehunter]

Thanks "mindcrime". So NECO was not giving me "fluff" when they said "negligible wear at the throat". Good to know.

Eric B.