Does lapping the barrel really make any difference? From that other thread a couple of weeks ago on cut vs button vs hammer forged I learned a whole lot I did not know.

When it comes to barrels I gather the stress relief process is the most important factor of all? Is lapping the tool marks out just some snake oil or is there something to it?

That would depend on the quality of the tooling used to rifle the barrel, and that would be with a direct relationship to the skills of the man doing the work.
Quality in, equals quality out!

Lapping a bad barrel will likely not make it good, but lapping a good barrel will almost assuredly make it better.

Some else said that before.......maybe Shilen?

MM

It's kinda like finishing concrete. You need to know when to leave it alone, let it rest or are you just playing in the mud.

It's all good, only if the person doing the work is good.

With barrels, I wouldn't want a "Broom Finish"..

Most custom barrels are hand lapped before they are sold.In most factory barrels lapping makes little to no difference.Fire lapping can improve a barrels worn throat.Also works good on Revolvers to make the forcing cone and barrel the same size.JMHO ,Huntz

The only barrel that I have had any real luck with firelapping was a Marlin in 444. It had a couple of tight spots in the bore that were evident when you pushed a lead slug through the barrel. One tight spot was under the rear sight dovetail and another was where the dovetail for the magazine tube was cut into the barrel. The rifle would group into no better than 3 inches at 100 yards and mostly larger than that. This was an unusually inaccurate Marlin in my experience and was going to get sold if it couldn't be fixed. I ordered a kit with bullets and lapping compound and followed the included directions. The bore looked much smoother and groups that measured 1 inch to 1.5 inches became what I could expect from that rifle.

I have to admit that I have tried it on a couple of other rifles without such dramatic success, but it did work on that Marlin.

For real efficacy, fine barrels are lapped after they are bored and before they are rifled.

Subsequent lapping might add a little polish, but only address stuff at maybe the micron level.

Yes, hand lapping help, but it has to be done when the barrel is new, other wise you will do more harm then good.

I have a savage in .223 that didn't shoot the light bullets very well when it was new, so I hand lapped it and it seemed to help. I generally hand lap anything that's going to be running a sabot as well. Otherwise, I don't do it much anymore, although sometimes I do clean with JB bore paste, which is kind of similar.

I have a Remington Model Seven stainless, and when it was new I fire-lapped the barrel. Before doing that I could see imperfections in the barrel. After, they were gone. I can't say it improved the accuracy or not, but I think it did. What I can see is that the barrel stays cleaner.

Steve,

I've run Tubbs final finish through a few and I believe they all shot a bit better. Certainly smoother and more even when pushing a patch through. Cleaned easier too.

I had the same experience with a Marlin 1894 in .25-20. The only tight spot, though, was over the magazine tube dovetail. Made a big difference.

Almost all quality barrels are lapped. Some are lapped after reaming the bore as well as after rifling. They normally use 180-220 grit lapping compound. If you finish with 400-600-800 grit the barrel will copper foul.

butch,

Are you saying that the "finer" finish actually fouls more? That seems counter-intuitive to me. Please explain.

That's exactly what happens. Beyond a certain point, and even smoother finish results in more bullet contact with the bore, and hence more friction, resulting in more copper fouling. This is why some barrelmakers caution against using JB Compound very much in their lapped barrels. Eventually it creates an even smoother bore. Instead they like the bullet to be "riding" on top of the miniature striations created by a slightly coarser lapping grit.

JB usually doesn't affect unlapped barrels, however, because their surfaces aren't as smooth in the first place. But it can. My .338 Winchester has a take-off Sako barrel, which despite being pretty smooth tended to foul badly. Chemical cleaners took too long, so I started cleaning it with JB every time. That got rid of the fouling, but it started coming back even quicker. I was about to rebarrel the thing because it became caked with copper within 20 rounds, but then DBC came along and solved the problem.

I had a rebored rifle that was a fouling SOB. After 10 rounds, the accuracy was gone and I could make a penny out of the copper deposits. I firelapped it with lead bullets and 5 rounds of 220 grit, 10 rounds of 320 grit, 10 rounds of 400 grit, and 10 rounds of 600 grit. Afterwards the accracy was slightly better, but I couldn't get it to copper foul at all. Only took a couple patches for cleanup.So based on a sample of one,I wouldn't have an issue trying it again.

Great analogy.

John,

Not being well versed on DBC, this seems to counter your statement that the smoother lapped/polished bore fouls more due to more bullet contact.

If I understand correctly, DBC "fills in the low points", creating a smoother bore.

Would that not be the same as "knocking down the high points" by fine lapping/polishing?

I suppose it could be that the miniature striations are left in place with DBC while the valleys are filled up, leaving less room for fouling to collect.

Any ideas why DBC seems to work, while too much polishing doesn't?

Thanks,
David

It might have something to do with the different surface of DBC as opposed to steel. But I don't really know.

I had one Wilson barrel that gave me fits. Finally I was good and mad and I attacked it with coarse auto valve grinding goop on a tight patch. I took care to be consistent, but I full stroked that mutha like I meant it for about ten minutes.
I'd go until the goop dried, shove that out with Hoppes Nine, then go again with another patch of valve crud.
Had a stop block on the muzzle and a stop line in back to make sure I didn't trash the throat any worse.
Dressed the crown, cleaned the bore to white patches -- and the darn thing started drilling them in. Still have that barrel, on its second rifle.

guessing your right....the copper prolly finds smooth steel "stickier" than DBC....

I'm thinking coefficients of friction. Check out drag racing tires. They're pretty slick for max friction (gripping) with the pavement.

With slicker steel barrels after too much polishing, seems to me friction is increased, creating more shear effect from the copper bullet (fouling).

With DBC, I'm guessing the ceramic material that's "cured" by fire into and onto the bore leaves a surface that has less friction with the bullet.

DF

could someone push me in the right direction to find this thread? sounds like one i could benefit from reading as well.
thanks in advance.

Hand lapping and fire lapping will help a barrel with tight spots, copper fouling, or to remove alligator skin from the throat...fixing those problems will improve a factory barrel. It can help a factory barrel with these issues, but leave custom barrels alone until the throat is toasted.

The problem is that there is not much you can do to a factory barrel to improve it, but also there is not much you can do to make it any worse either...factory barrels are about as good as $10 can make them.

There are some older posts around the internet on how to find and remove tight spots in the bore, but the procedures are fairly logical, and anyone that really should be attempting it can probably figure it out.

Maybe DBC is filling in marks that are across the bore surface, whereas lapping marks are along the length of the bore.

Probably the answer. Never thought of the difference in friction coefficients.

Wonder what would happen if a barrel was polished, then the DBC coating applied?

A gunsmith friend of mine has built several benchrest rifles for some local guys in Texas--not competitors, just guys that get together to shoot on weekends. All the barrels are either Liljas or Kriegers, and all have been DBC'd. Last time my friend reported the rifles all had a couple thousand rounds through 'em without the bores being cleaned, and were still shooting tiny groups.

Hard to argue with success. I'll have to try the stuff.

I want to say I read this same thing in an old Precision Shooting magazine. I'll have to dig around and see if I still have it.

I must have missed something,or I am just ignorant, but what is DBC.

DynaBoreCoat

You can get DBC from Brownells and other sources. Just follow the directions making sure to get that barrel squeaky clean. I really enjoy my Hawkeye bore scope in this regard. I can see when it's really clean, not depending on patches without blue. That method doesn't tell anything about carbon build up, etc.

My DBC treated rifles seem to go on and on, like the Energizer Bunny, without fouling or a need to be cleaned. I usually clean hunting rifles at the end of the season whether they need it or not. Old habits are hard to break...

DF

I've had two barrels I've fire lapped. They went from 3 MOA to < 1 MOA. The barrels looked like someone had drug something through them before I fire lapped them. Not had an issue with them since.

I think they will really work if the barrel is in need for lapping.

I'm not sure about doing it on a regular basis, though.

I've done considerable experimenting with fire-lapping. In some rough barrels it will make a difference, and in some it won't, I suspect due to where the real problems in the barrel are.

Most of the "lapping" occurs in the inches in front of the chamber, probably because they lapping compound tends to wear off the bullet as it heads through the bore. Quite often, the area in front of the chamber--especially the throat--is quite rough due to machining marks left by the reamer. This is most of what gets smoothed when we "break in" a barrel by shooting a bullet, then cleaning down to bare metal, then shooting another bullet, cleaning, etc. It also causes a lot of the copper-fouling in a new barrel.

Fire-lapping smooths this area out very quickly, in as few as 5-6 shots, one reason I don't go through the time-consuming (and expensive) process of shooting 20-30 normal rounds and cleaning between each.

Fire-lapping will also smooth out the cracked and eroded area in front of a barrel that's been shot a lot. This slows further erosion, because militray studies have shown the cracking tends to keep hot gases circulating in the throat area, and heat is what burns out barrels. Smoothing the cracks allows hot gas to travel down the bore easier--and also usually improves accuracy as well.

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/9471383/1

This rifle, after fire lapping. 1977 Ruger #1V .22-250, three groups in a row at 100 yards.



It had previously been promising, but fussy. It would put three in one hole, then toss the next two 1.5" away. I had tried a multitude of Ruger #1 tricks, without much luck. The Wheeler Engineering fire lapping kit settled it down. Besides approaching 1/2 MOA with preferred loads, it also is now unfussy, and will shoot TSX's one MOA or less. I'm guessing the lapping improved its vibration characteristics.

That said, I tried it last year on a Kimber 7mm-08 Montana, which shoots well with a warm barrel, and poorly with a cold barrel. The barrel scopes rough inside. FL didn't fix the problem.

If you have a problem rifle, it's worth a try IMO.

If you call Douglas and talk to them.
They will tell you that a properly buttoned rifle barrel doesnt need to be lapped.
Douglas doesnt lap there barrels.

dave

Devil's advocate: Of course someone will ask how many Douglas barrels do you see in competition winning equipment lists compared to lapped buttoned barrels like Lilja, Broughton, Hart, ...

(Purely a debate point, I have nothing personally against Douglas.)

I had a Douglas once and it fouled like crazy. Example of one, but I would not buy another.

I will not opine on a factory barrel as I have very few. As Mule Deer says, the freshly reamed throat has "fluff" from reaming. I have found that if you take a bronze cleaning brush and wrap a little 0000 steel wool around it and lap the throat driving it with a drill motor you will find that you don't need to do a formal break in.

And I have had numerous Douglas barrels, and can't recall one that was a real fouler. Examples of one don't prove much.

One in particular, a stainless on a NULA in .257 Roberts Ackley Improved, broke in as easily as most hand-lapped barrels. I shot it maybe 20 times at its first range session, then cleaned down to bare steel. There was little copper-fouling then, and even less after the second range session or maybe 30 rounds. After that I cleaned it at 60-75 shot intervals, and it didn't take more than a few patches with any decent solvent.

I haven't cleaned my rifles in about a year after DBC. To the naked eye there is very little fouling. I don't have a bore scope to check it out, but accuracy hasn't dropped off either, so I'm not inclined to worry about it.

I really need to DBC my muzzleloader and 22 LR!

DBC works great in both. In fact some factories are putting it in their muzzleloader barrels.

thanks!

Does a 22LR benefit from DBC?