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Discussion Starter · #1 ·
There was some discussion in another post concerning barrel break in.
Here's something I found in Precision Shooting Magazine that may be of interest.

Bore break-in and cleaning. The break-in procedure pioneered in PS some 20 years ago still is used by most savvy shooters: thus, shoot one round and clean for the first 5 to 10 rounds, shoot 2 or 3 rounds and clean for the next 10 to 15 rounds or so, and clean after each 5 or 6 rounds until the barrel has 50 to 100 rounds through it. This schedule, let it be emphasized, works best for custom barrels. It may help one of the better factory barrels, but the bores of many of these are too rough to benefit. (The latter often are good candidates for hand lapping or fire lapping). The “clean” part of the shoot-and-clean break-in means really clean: i.e., the very hot (5000°F-plus) powder gases should impinge on a bore surface free of both powder residue and jacket metal from the previous shot. Most of the liquid bore cleaners on the market, used with a cloth patch or bronze brush, will remove all powder residue in the short time frame of break-in firing but typically only a part of the jacket fouling. Several of the more aggressive liquids, like Barnes C-10 or Sweets, remove most or all jacket fouling—but one can be sure of this only by looking with a bore scope. Well-applied pumice cleaners, consisting of sharp fragments of volcanic glass that is harder than copper and softer (we hope!) than barrel steel (e.g., JB and RemClean), remove all jacket fouling from all but the roughest factory barrels. Abrasive cleaners using a grit harder than steel, but of grain size fine enough so that there is very little abrasive wear of the bore surface, will remove all that jacket fouling. My recommendation of these prior to this conference was Corbin’s Bore Cleaner (PSad), a mixture of 15-micron size (about USA #600 grit) alumina particles and a liquid carrier. Alumina (corundum) has a hardness close to that of silicon carbide. This stuff not only cleans the bore but very slightly polishes the bore surface. Darrell Holland (PSad) brought some of his Witch’s Brew to the conference. This is an aggressive abrasive cleaner that seems to work about as well as the Corbin. Let me emphasize that these two cleaners are for break-in and thickly fouled bores: they may be too much for everyday cleaning. Darrell also offers a special oil for break-in. Other shooters over the years have recommended lightly oiling the bore before each break-in shot, but Darrell’s is of high flash point and so should resist burning off more than most light oils.

Two shooters suggesting other methods of breaking in barrels are Pete Forras and Norman E. Johnson. Mr. Johnson (who was not at this conference) gave a detailed account (American Rifleman, February 2000) of lapping barrels with abrasive patches on a cleaning jag. He first examines the bore with a scope to judge whether or not to lap it. In his experience the barrels of hunting rifles benefit more from this method than match-grade barrels. His method is worth consideration, in my opinion, for those match barrels that do foul.

Pete fire laps each of his new barrels, factory or custom. His experience is that many match-grade barrels are more accurate and easier to clean after mild fire lapping than if put through the shoot-and-clean sequence. This topic obviously is controversial. I hear mixed signals on it: shooters of long bench experience will say on the one hand NO WAY(!!) should their pet barrels be fire lapped, but on the other hand will admit that their few barrels that fouled badly might well have benefitted from fire lapping. Pete’s position is that fire lapping does not harm a hummer barrel and that it may markedly improve a marginal barrel. I certainly can’t resolve this point, but I do suggest a modus operandi for anyone trying this method. Basically, one should commence fire lapping a new barrel only with a grit equal to or slightly finer than the “grit equivalent” finish of the bore given by its maker. To explain: a barrel maker who hand laps a bore with #400 grit on his lap produces a 400-grit-equivalent finish on that bore. If this sort of information is not available from the barrel maker, or if the bore was not lapped, one in theory should use the depth of the microgrooves produced by the cutting tools (esp. during reaming for a button-rifled barrel) to arrive at a grit-equivalent figure. This requires a microscope to look directly at the surface or by using some other sophisticated technique. In most cases one must simply estimate the grit to start the fire lapping sequence. Pete now fire laps by David Tubb’s Final Finish System (1-806-323-9488), which uses grit-embedded jacketed bullets over charges of fast-burning powder in amounts about 10% below maximum. Note that Tubb’s system gives markedly higher velocities—and better obturation of the bullet—than those loaded according to the NECO fire lapping kit’s instructions.

Pete’s conference got into the nitty-gritty of bore fouling. As a starter I fired my .220 Swift with 26" Krieger barrel, starting with 1,130 rounds through it, 194 times without cleaning. The load was near-max using H4350 and 52-gr. Hornady A-Max bullets. The first cleaning patch after that long afternoon’s shooting with Marvel (like Kroil but it costs less) went down the bore easily and only traces of copper fouling were visible at the muzzle. This rifle previously had been shot 90 rounds without cleaning, all with good accuracy on PD’s out to 500 yards, so I knew it was a very light fouler. (And, of course, older readers will remember Jim Carmichael’s writing on this great old cartridge, in which he emphasized that a good Swift barrel won’t foul any more than other high-intensity cartridges.) My barrel’s performance is perhaps better than that noted by Palma shooters also using John Krieger’s barrels, for the Swift puts out about the same charge of powder as a .308 Win., but the bore area of the Swift is only about 53% that of the .308 and its bullet travels about 25% faster.

The biggest test of barrel fouling was made by Pete himself. He used his .223 Rem. wth carbon-fiber wrapped PAC-NOR barrel, fire lapped by David Tubb’s method, as mentioned above. During the three-day shoot Pete put 930 rounds through this barrel without cleaning it: all Black Hills factory rounds, 780 loaded with the Barnes VLC blue coated 40 and 50-grain bullets and 150 loaded with the 50-grain Hornady V-Max bullet, all bullets ahead of Ramshot Xterminator powder. Actually, from previous shooting Pete knew this barrel would pick up very little jacket fouling, even in such a marathon, and this test was made primarily to check out the claim made for

Ramshot powders by their Belgium powder chemist (yes, Ramshot, like the other powders we use, is made outside of the U.S.A.) that they lay down little or no powder residue. The first cleaning patch wet with Kroil that Pete put down the bore went easily and showed none of the resistance associated with build-up of powder residue or of coating from the Barnes VLC bullets. Why such fine-grained ball powders as the Ramshot varieties shoot cleanly, though, is a mystery to me. Ball powders, to begin with, need a pronounced deterrent coating to control their burn rate, and that coating in many other ball powders tends to lay down some fouling. I’ve used Ramshot’s slow burning Big Boy powder behind heavy bullets in the 6mm Rem. and .270 Win. cases, finding that even such large charges (64 grains in the .270) gave little powder fouling. PS readers interested in trying Ramshot powders, which are not yet in many local gun shops, may order them from Kinneman’s (PSad).
 

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NO WAY JOSE!
Am I putting any abrasive down my barrels. I read a thread a while back. A gent by the name of, lets see a... Gail McMillan, if memory serves me correctly. He was talking about how the whole barrel break in myth got started. BR rifles only give top performance for 3000 or so rounds. After that, it's all down hill. Anyway, clean the hell out of a new BR barrel for the first twenty rounds or so, you put wear and tear on it. Won't last as long. More barrels get sold. And we are not even talking abrasives. Mr. McMillan also stated that any abrasive bore paste gets used on his barrels, the warranty is voided. I'm sure the same goes for fire lapping.
My brother-in-law fire lapped a .270 of his. Now he can load a O.A.L. that is somewhat longer than most. He now has a lot of freebore in that rifle.
 

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Mike,
There is a world of difference between a skilled gunsmith, with years of experience in a barrel shop, hand lapping a bore down to a specific controlled tolerence and micron of finish, and a gun owner running all manner of abrasives down his barrel untill it seems smooth. A smooth finish barrel is not a garantee of accuracy. For the average gun owner, the easiest way to improve a barrel is to redo the crown. The improvement can be dramatic. If a barrel is all that rough, lapping will merely increase tolerences. One other thing I have found. It is best to take gun rag articles with a large grain of salt. Many of the authors are full of s___! Did the author of that article mention rounding? When you use abrasives on a barrel you round off the edge of the rifling, you know, lands to grooves. This can be verified with a bore scope, no opinions here. Accuracy will also drop off, that can be demonstrated objectively, on the range. Like I said, not my barrels.
 

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Discussion Starter · #6 ·
Bill,
I understand your position, and I am not endorsing anybodies opinion on lapping barrels or nor lapping barrels. Opinions are just that. No more or less.

Magazine writers do seem to have a... how shall we say, broad sense of reality. It's not just gun mags either. Pick up any hot rod mag and it borders on halarious at times.

There does however, seem to be some empirical data to support fire lapping. I have seen information presented on the NECO web site, http://www.neconos.com/details2.htm , that says it's the best thing since canned tuna, but then again, they do have a vested interest in talking up fire lapping, since they sell the kits to do it. (Pass the salt, please.)
I mentioned in a post some time ago that some poeple swear by fire lapping and some swear about it. I guess that pretty well sums it up.
 

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Mike,
Who the blue blazes is Bill? And by the way, what happened to the font and appearance of this board? Maybe it will be back to normal by the time someone reads this. One more thing. My brother-in-law used the NECO kit and like I said his rifle has more freebore than a Weatherby. But, it does not foul as bad and it cleans easier.
 
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