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It is possible that lapping of last 3-5 inches of barrell will improve groups as much as lapping barrell complitely. Maybe 3-5 inches enough to shoot each bullet in exactly same direction? :?: :?:
 

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car5car said:
It is possible that lapping of last 3-5 inches of barrell will improve groups as much as lapping barrell complitely. Maybe 3-5 inches enough to shoot each bullet in exactly same direction? :?: :?:
What lapping a bbl does is smoth it out, ie polish it. What makes a bbl accurate is being very uniform and consistsnt diameter, straight, and tight tolerance. There is also some diffring opinion on some other things, but this is general. Several other factors like stressed metal etc could be, but people differ on opinion. To answer your question, probably not. If you are going to lap the bbl, you should lap the whole thing. Any reason why you only want to lap 3-5 in insted of the whole thing?
 

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Would be best if you were going to lap the barel, to just do the whole thing. I dont really quite understand why only the last portion would be done. Also, depending on the qaulity of the barell, it might not even need to be lapped at all. An old barell with many rounds shot through it might require a lapping. A brand new schneider or shilen more then likely wont. Purpose of lappings as John has mentioned is to smooth out the barell so that it is easier to clean and clears out whatever tool marks are left in the barell so that when the round is fired it wont nick and burr the bullet. It will have a smooth travel. Tubbs Final Finish I hear is a good product to do the lapping with.

Respectfully,
Tyler Consugar
 

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I also wanna make this clear as well. Waht makes the barell shoot rounds in pretty close to the same spot are the "harmonics" The harmonics of a barell are the vibrations it makes when there is round that is fired. Bull barells are straight tapered and are alot more rigid then sporting type barells. So harmonics on these wont be as hindering as they would be on a thin, sporter type barell.

Respectfully,
Tyler Consugar
 

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If your going to take the time and money to lapp a bore you might as well do the whole thing. The un-uniform rifling in a cheap / abused bore tears at the jacket of the bullet and will cause extra fouling and make it much more difficult to clean the bore and obviously make it less accurate.

The first thing you should do is have a good barrel smith look at your bore with a bore scope. Then, depending on how bad it is have it fire lapped and then hand lapped or if its not so bad just hand lapp it.

The Rifleman
 

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I'm not sure where to begin on this thread, there seems to be much confusion of the process of barrel lapping.

Barrel lapping is the process of using lapping compound {composed of fine abbrasive, oil and clay} and using it to polish and deburr the inside of your barrel.
The goal is to remove the horizontal tooling marks left when the rifling was cut. These rifling marks will speed up the fowling process and can be thought of as speed bumps that disturb the bullets natural path.
I don't even know if it would be possible to just lap the first 5 or 6 inches of a barrel. It would require more work than doing the whole barrel.

If some how you were able to do this you would ruin a perfectly good barrel. The purpose of lapping a barrel is to create a uniform surface for the bullet to travel. If you where to fire a bullet out of a half lapped barrel the bullet would travel along the lapped section and then hit a speed bump while traveling along the unlapped part. Thus disturbing your bullets natural path and sending it flying. This can mean the difference between a .25 moa and a 1.5 moa shot.

In the last few years I read more and more about fire lapping. If you really care about your rifles stay as far away from that stuff as you can. If you’re not careful you can open up the bore of your rifle too much and turn your 1 moa rifle into a 5-minute rifle. I asked my gunsmith about it and he told me it's great for him because people buy this stuff and end up doing something wrong and sending the rifle to him. A lot of the time they need a new barrel. Just because some ones name is on the product dose not mean he uses it. David Tubb dose not fire lap. He has a team of gunsmiths at his disposal and there free.


True hand lapping is a brute strong and time-consuming process. It also requires great skill to do PROPERLY. This is something you don't want to try at home, if you don't have the right tools or skills you will ruin your rifle. My gunsmith has his son do all of the lapping work that comes into the shop.
This is what we pay for when we buy a barrel from Montana rifle co. or lilja. A precision instrument. Barrel harmonics are free when the barrel is free floated which is standard on every new rifle today.If you have a crap barrel your not shooting any groups. So barrel harmonics are not the sole reason why a rifle shoots groups.
If you have had your barrel hand lapped NEVER fire lap your barrel you will damage it.
Guys you might want to do a little reading on the subject. I think you would both bennefit from reading The military and police sniper by Mike Lau. There is a good deal of information on gunsmithing techniques
cheers,
Kenshin
 

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Correct me if i am wrong but from what i understand Fire lapping is the best way to remove and smooth over pitting and other major obstructions in worn / neglected barrels? Hand lapping is for finely polishing and getting rid of tooling marks?

I agree and understand that hand lapping and then fire lapping is not a good thing to do. Allthough, fire lapping and then hand lapping is ok from what i know and understand.

I have never hand lapped a barrel myself, so i am curious. How long does it take to remove your average tooling marks by hand lapping? How many passes through the bore? Are there any books or websites that have DETAILED information on how to hand lapp?

Thanks for any and all info.

The Rifleman
 

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Hey guys,
I was not fully sure of many of the details so I called my gunsmith to answer your question. The following is a loose transcript of what was said

Q: Dave whats your take on fire lapping VS hand lapping and can you explain the process a little.
A:
The fire lapping process is a down and dirty do it your self method for the at home do it yourself person. When a gunsmith or barrel maker hand laps a barrel the process can take over 700-1200 passes. It should really only ever be done once to a barrel in its lifetime. The process can require 3-5 different types of lapping abrasive and after every 40-80 passes the barrel is inspected with a bore scope. All good gunsmiths should have a bore scope.
All this time the gunsmith is in controll of the bore rod. If pressure and allignmet are not true then a "spot" or "vegas" can form. If this happens throw your barrel away or drill a larger caliber.
When a person fire laps they load abrasive impregnated bullets into their rifle and shoot them off in a sequence. After all the abrasive bullets have been fired your barrel should be true. I sincerly doubt it.
In the fire lapping process there is "NO" controll of the bullets. So if the first few bullets do not take out the larger tool marks your kit failed and you just washed $30 down the toilet. If you shove another kit down your barrel your almost sure to create a vegas or open up your barrel or throat to much. In effect you just turned your 1 moa rifle into a 3 moa rifle. If you try to fire lap and then see it did not work DONT TRY ANOTHER KIT. Chalk it up to a life lesson and then take it to a gunsmith for inspection.Most of the time I can undo the damage.
The biggest mistake I see and this has happend 3 times is after the kit was used there so excited to see how well it worked they shove a round into the chamber and fire without cleaning the rifle. This is like dumping sand down the barrel and shooting off a few rounds. All 3 needed new barrels and a little ed-u-ma-cation

If you have an old hunting rilfe that fouls eaisly or you have an inexpensive gun of some kind where precision accuracy is not a concern, have at her.
I know people that have used the process to lap inexpensive ar-15's and has helped a little. I've never had anyone come to me and say this process is amazing. Fire lapping should NEVER be done to a precision rifle. Why would you spend $1000.00 plus on a precision rifle only to spend $30.00 on a gimmick that should be done by a qualified gunsmith?

If you want to learn how to lap barrels go to a quaility gunsmith and pay him or her to teach you how to do it properly. I'm sure there are websites or books, but the trial and error process will be expensive and some what redundant.

Thanks to Dave M for the information
Hope this helps.
Cheers,
Kenshin
 

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I've heard the same thing about fire lapping. The bad thing I see is that the abrasive on the bullet gets imbedded in the bore along with copper and powder fouling, then you fire another abrasive bullet over the fouling and embed more in the barrel. If you were to clean after every shot fired, this might not be a problem, but firing a string without cleaning can be a bad thing. Or so I hear, but makes sense to me.
 
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