Barrel lapping

T

tenring

New member
Is it possible for a do-it-yourselfer to produce a professional quality barrel lap? What is the proper technique to do so?
 
tenring said:
Is it possible for a do-it-yourselfer to produce a professional quality barrel lap? What is the proper technique to do so?
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Of course it is "possible".

That said, the odds of getting a professional job on the first barrel one tries to lap with out study, training, practice on some old barrels, and effort are probably pretty small to zero.

But it is a skill that can obviously be learned. The key will be to invest the due dilligence to learn the right way to do it, get the materials and tooling ready, practice on some old barrels to work out the technique, then, when you have demonstrated to your self you have the skill in hand, go for it. I don't know what books will have good information, but it doesn't seem like it should be rocket science - folks have been doing it for well over a hundred years.

Start by doing some searches on the net, on this and other forums and the net in general, find a book or two by people who know what they are doing, spend some fun time getting your mind around it, and then go have fun doing it.

I did just that with fitting and chambering barrels this past winter. It was a great way to spend cold days in the study learning what others did, having some lively discussions here where I learned a lot, and then time in the in the shop making tooling, lots of tooling. Then I did it, and so far it looks like it worked out just fine.

Fitch
 
Slugging away

This is probably a definite way to improve your barrel accuracy..

Do it like Ben Hogan practiced golf. He said the answer to better golf was in the dirt. Meaning if you practice like a son-of-a-gun you will eventually bear fruit.

;)
 
food for thought. most decent barrel blanks have already been lapped, so im going to assume you want to lap a finished barrel. again assuming you possess the skills required, when your finished lapping your barrel you need to cut off both ends because they've been loosened during the lapping.
 
Well. . . .

I wouldn't think of lapping my ppc or br barrels; but I have some factory barrels that need it. I think you guys just talked me out of it. Thanks.
 
The odds are about the same as a do-it-yourself heart valve replacement. That's why they're professional.
 
More info..

Chet Amick was a rimfire shooter. He learned to lapp barrels.

Some barrels need to be lapped but may be others don't.

If I could accomplish 20% of what Mr Amick did I'd be happy.

Check out what he did in rimfire or ask a few of the Great rimfire shooters what they think.
 
Chester was a fine gunsmith and was for some time before he came to rimfire. He would probably not be representitive.
 
It's OK if you do it correctly!

I am in the process of producing a DVD on this very subject as part of my "Extreme Accuracy Series" of custom gunsmithing DVD's coming soon. We finished filming the "Slugging and Hand-lapping Rifle Barrels for Accuracy" video this week and it shouldn't be too long and I'll have the DVD's ready to sell.

First, I show and explain in detail how to"slug" the bore to evaluate a rifle barrel, and then go into detail on how to pour a lead lap and hand-lap a rifle barrel for top accuracy.

I do it all the time in my shop and I recommend recrowning the barrel after lapping it, but you normally can do it without having to rechamber it. It often makes a tremendous difference in the accuracy potential of a factory barrel or a custom barrel that has problems!

I'll try to let people know when this is available, or else keep an eye on my website: www.gordysgunsmithshop.com

Hope this helps answer your question!
Gordy Gritters
 
Hand lapping a barrel is not dangerous to the barrel if you pay attention to what you are doing, because it takes material off in very small increments.
I have taught apprentices to do it in only a few hours and they do a very good job. I know there are other ways to do it but this way works for me.

I mainly do new barrel blanks but I have done many many finished barrels. When I get a blank I cut off to length, I keep the cut off piece and use it as a mold for the lead lap. If you contact a gunsmith they may have a pieces of barrel you can use. I then take a threaded one piece rod and put on a tight fitting cleaning patch and run it down the barrel, where I feel it get tight I make a mark on the rod with a marking pin then when the patch feels loose again I make another mark on the rod, I do this the whole length of the barrel, now I lay the rod on top of the barrel and mark the barrel with the start and end of the tight places. I heat up the piece of barrel I cut off and saved with a torch and then before it cools I put in a jag and pour in the lead to make the lap, as it cools the lead lap can be pushed out, I make 5 to 7 laps.
I place a little rubbing compound on a piece of tempered glass and place the lap in it then with another piece of glass I roil the lap back and forth until the lap is coated. now I place the lap into the barrel and move it close to the mark on the rod I push the lap back and forth between the marks after 6 to 8 passes I make a couple long passes, 2 to 4 inches past the marks,to even out the polishing. After 30 or so passes I reapply compound and and continue, if the lap feels loose I use a new one, then I go to 400 grit and finish with Simichrome. When finished the bore will shine like a mirror.
 
Koginam, What is the source of lapping compound? I have a need to do some die lapping.
 
IIRC custom lapped barrels are finished undersized and lapped to the correct bore size.

Factory barrels are finished to the correct size first.

Lapping a factory finished barrel is just going to open up the bore. Why would you want to do that?
 
I have some compound made for valve grinding, I have 4 differant grits but I use mainly only the finist two, along with a finish pass or two of Simichrome.
 
Simichrome has ammonia harmful to brass and Stainless. Flitz is safer.

Only do this with tomatoe stakes or factory barrels that just don't shoot.

http://www.davidtubb.com/finalfinish.html

Flitz the barrel with a mop and fire 5 longest bullets for the caliber. Clean, repeat until no rough spots in bore or goups tighten. Best on used factory guns. Do scrub the copper out of the barrel first.
 
koginam said:
Hand lapping a barrel is not dangerous to the barrel if you pay attention to what you are doing, because it takes material off in very small increments.

<snipped good stuff>

When finished the bore will shine like a mirror.
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I like your procedure a lot. I think I could do that. I don't have a candidate barrel at the moment, but I saved your procedure in my growing note book of tips and tricks.

I have a question. I know folks have used lead since time began, but out of curiosity, could Cerro-Safe be used instead of lead? If it could, it seems like it might be easier to work with. One could clean the grit off it, degrease it, and reuse it I'd think.

Thanks
Fitch
 
I haven't tried Cerro-Safe I melt lead wheel weights because they are a little harder than pure lead. After lapping I clean the bore and lightly oil, I have not had any problems with Simichrome. Tubbs final finish is for fire lapping and is a good product for quick lapping on really rough barrels, but hand lapping is a more controlled way of polishing the bore.
 
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