Bore lapping

[gunnut310]

Which do y'all feel is the better way to brake in a new barrel, (have done it both ways) lapping or shoot and clean method? Maybe a combination? I usually lap my AR Barrerls. The rifle I am in need of breaking in, is a Remington 5R mil-spec in.308.

[Dufus]

I have always lapped.....when needed. Some barrels are ready to go without any prep work.

[Scorch]

The 5R barrel is already lapped. Unless you have many years of experience, you probably cannot improve the 5R barrel by lapping it.

To break in barrels, clean them well, use a bore conditioner, and follow a shoot/clean/shoot/clean regimen until the bore is burnished. There are people who will swear up and down that doing so is a waste of time, and then there are those who believe it adds to the quality of the barrel. Several barrel makers recommend a break-in procedure, and some then internet experts wheel out the old Dale McMillan article saying it just uses up the barrel. You pick who to believe and go for it.

[Don Fischer]

I think break in however it's done is a waste of time. Then again I think barrel break in is necessary. If you don't believe break in is a waste of time, try this. Start off with 20 test loads. Shoot them up one at a time then clean the rifle well. Every time you shoot your rifle, clean it well and I do believe your gonna find that the more you shoot and clean, the better the rifle shoot's.

I tried the break in method with my 6.5x06, I wanted to be very careful and get all I could out of it. If I remember right, I fired 20 shot's cleaning and cooling the barrel. When I got done, it was shooting as well as my 308 and 25-06, they both went well under a inch at 100 yds. Seem's to me that I wasted 20 rounds doing that break in!

Down the road I got a new 6.5x55. Didn't break it in and it run's right at an inch and a bit under. Got two 243's since then too. Didn't break in either and both shoot with the 6.5x06. That is consistently under 3/4" at 100 yds. A lot of the thing I think shooter's promote are more feel good thing's rather than necessary. But if you think it is good to do or especially if you think it's better for your rifle, go for it! If you have a match rifle and every thing was done to it and it won't shoot well under 1/4" at 100yds, your not gonna win to many matches with it any way. Guys talk about extreme reloading habit's and I have tried a few of them And if they made a difference, I couldn't tell! I've heard guy's saying remove the burr on the primer pocket inside. Well I made a tool to do it, did it and if it was any improvement, you couldn't prove it by me. Seating depth is another thing, ya got to be x one thousands off the lands. I have no idea how far mine are but just off the lands. Been doing it that way for years and the only premium bullet's I ever used were Nosler's. I don't know how the stuff about thousand's off the lands came about.

Reloaders for the most part are a screwy lot! Most are looking for the rifle that will actually shoot a one hole group, may have already been found but the shooter that can shoot one hole hasn't been found.

Pretty windy way of saying if you want to break in your barrel, go for it. Won't hurt a thing!

[gunnut310]

Thank you for all the information. I will shoot and clean for 20 rounds and see where it's at. I haven't put the first round through it yet. First factory custom rifle I've ever bought. Which brand of barrel conditioner to y'all consider the best? (I don't know what all Remington does in prep. on its 5R rifles.)

[Scorch]

The easiest bore conditioner (actually sold as such) to find is Tetra Bore Conditioner. I use Militec-1 as a bore conditioner and am very pleased with the results. I think just about any really fine oil will work, but don't have any evidence to support that idea.

[Unclenick]

I would avoid any conditioners during initial break-in as they typically have some form of anti-friction agent which can reduce the ability of a passing bullet to pull off small burrs and can cover up the prime indicator of break-in success: whether or not the barrel is less prone to picking up copper. It may not affect burnishing action (pushing down on the metal), but you want to see the affect of any improvement.

Personally, I avoid fluoropolymers in bores due to grief that occurred with Teflon (PTFE, a fluoropolymer) in bores when it was tried 25 years or so ago. It turned out the anti-friction properties of the Teflon changed as it got hot, with the result some experimenters found accuracy actually deteriorated during strings that warmed their bores in competition. For hunting, or other applications where only a round or two is usually fired at one time, it does no harm, AFAIK.

Get a bottle of BoreTech Eliminator and a pump sprayer. Fire one round. Pull the bolt. Examine the muzzle for traces of copper. If you have a borescope, even better, as you can then look for copper about an inch or two past the throat where it tends to be worst due the bullet being there when the pressure peaks. Try to get a sense of how much fouling is there. Point the muzzle down over a light background and squirt a couple of pumps of Eliminator down it and watch it run down to the muzzle. Let it sit three minutes. Run a patch through and pump another squirt or two of Eliminator in, and in a couple more minutes patch it again to see if any significant amount of copper is left. If it is, you should repeat until it's gone. (Note that you have to use a plastic, steel, nickel-plated, or Boretech Proof-Positive jag with this cleaner as it attacks a brass jag so fast it will turn the patch light blue just from contact with the brass.) Run a rubbing alcohol patch through to remove traces of the cleaner, then a dry patch. Repeat the firing and cleaning process.

Usually at somewhere around the sixth round or so, you start to see the amount of copper left behind after each shot is decreasing. If the copper grabbing remains bad all the way to twenty repetitions, you have a problem that only firelapping or hand lapping will likely solve.

The process tries to do a couple of different things. One is to remove all copper between shots so as to re-expose rough parts of the bore for the next bullet to try to act on. The second is the barrel is subject to pressure distortion during firing, and if you have a button-rifled barrel that has not been stress-relieved by the maker, then pressure distortion can affect the residual stresses from the rifling job and cause the barrel to try to take a set to some degree. By cooling between shots, you insure that any set that is going to occur happens when the barrel is in its cool shape, which helps discourage heat walking when shooting at a pace that doesn't let it cool. I would not expect this to make a difference with stress-relieved barrels or with cut-rifled barrels.

Good luck with it!

[tobnpr]

What exactly do you mean by lapping? Fire lapping?

[gunnut310]

What all does Remington do to their 5R rifle barrel s before selling?

[Unclenick]

I think what Remington does with the new barrel is install it on their receiver then assemble the gun. AFAIK, their barrels are made on contract by a fellow who learned the 5R method from its inventor, Boots Obermeyer, then underbid Obermeyer on the Remington business. However, Obermeyer's web site indicates he's had a lot of military business. His barrels are all cut-rifled. Check his FAQ for more information. For even more, you'll need to call him.

I've firelapped a couple of barrels that the borescope showed no actual defect in; one military and one Savage. Both simply accumulated copper fouling rapidly enough that accuracy deteriorated before I could finish completing a match course of fire without stopping to clean them (often not allowed). It helped immensely, reducing cleaning effort by about a factor of 6 (as measured by the number of strokes and patches involved in getting all copper traces out). It opened up the breech end of the barrels about half a thousandth and the muzzle end about two tenths. Both remained well within standard tolerances and bullets are easily upset that far by normal bore pressures, so there was no apparent impact on velocity or loss of accuracy. No improvement, either, but that wasn't what I needed. With stressed surface steel removed from the throat, they lasted as long as any new barrel usually does, though I did have to also re-crown the military barrel to clear away minor funneling. The Tubb's Final Finish system uses a similar principle to revive shot out throats.

[T. O'Heir]

Breaking in a new barrel isn't necessary. And lapping is not any kind of breaking in thing anyway.
"...Some barrels are ready to go without..." All barrels require nothing more than cleaning.

[Jim Watson]

I read on the internet that there are Mike Rock 5R barrels on top of the line Remingtons and Remington made 5R barrels on the plain vanilla guns.

I have two aftermarket barrels which I "broke in" according to the maker's recommendation. It consumed no barrel life per McMillan, because I used the time and ammo to get initial zero and chronograph readings that I used to get on target for F class shooting.

[hooligan1]

T Oheir, you need to write a book about your knowledge of everything guns, I would find it interesting.
Some people think barrel break in is unnecessary, but Id like to believe that barrelmakers who encourage a break in do it for the benefit of the barrel itself.
After talking with the fine people at Douglas barrels, I broke in my 3 Douglas barrels using their method, I also zeroed my rifle in during this process. What did it waste? A little bore solvent? Hell I was going to shoot the handloads anyway, might as well serve 2 purposes.
These 3 rifles shoot wonderfully and I havent lost any leade to erosion from it. Do what you like, as you know I do too.

[std7mag]

I had just read an article on Accurateshooter by McMillin that claims not to "break in" a barrel.
According to him when the barrel is produced it is at it's best. Accuracy only goes down from there.
He does specify about using a sharp chamber reamer.

[tobnpr]

I'm usually a fan of no break in, but Krieger provides an interesting explanation of why at least a few shots of "shoot one and clean" can be beneficial re: plasma depositing copper further down the barrel and accumulating where not needed/wanted.

Krieger is probably used more in competition rifles than any other barrel, FWIW...

Scroll down to the "Break-In & Cleaning":

https://kriegerbarrels.com/faq#breakin

[HiBC]

Just another opinion.
Not all barrels are made with the same care.IMO,if you are working with a barrel from a good custom barrelmaker,I don't think we inexperience amateurs are going to improve on their work with anything we are likely to do.
I don't think beneficial lapping is done by any method involving bore brushes or mops and anything from Clover valve grinding compound to JB or Flitz.
I think you have to pour melted lead in the barrel around a brass screw in a cleaning rod to make your lap.If that's news to you,its probably best to leave it alone.
While I don't think our barrelmaker needs our help on the bore, usually someone else cuts the chamber after the barrelmaker is done.The chambering reamer leaves some little burrs on the trailing edges of the lands.It may leave some light cutter marks.
Its these little chambering flaws that may need "breaking in".IMO,its about little copper micro-flakes from these burrs.I want them cleaned from the bore between shots.I don't want the next round to impress them into the relatively soft barrel steel.
You may disagree,but I formed this idea reading Krieger.

I did once transform a poor barrel with firelapping.IMO,if you rebarrel and get substandard performance,what do you have to lose? This was a "bargain" pre-thread,pre-chambered Midwells or Brownway barrel,30-06. I used cast 30-30 bullets and #9 diamond mold polishing compound. Pretty darn fine.I forget the micron.
At the muzzle,I could see button galling and bore reamer marks. It fouled badly.The lapping fixed it and it became quite accurate.
Just be aware of grit progression.IMO,forget it.Only use your finish grit.
Why? 320 grit rocks are much larger than 900 grit rocks.On the same dia bullet,the 320 cuts a bigger hole.The 900 won't take out the 320 grit marks.
If you want to finish with 900,just use 900.

But,as I said,thats on a "Nothing to lose" barrel

[tobnpr]

^^^
This.
I won't touch 'em. More likely to do harm, than good. Like I said, by definition, you're removing metal. Enlarging the bore and rounding the lands.

Which is why I leave it to the barrelmakers.

[zipspyder]

I have to agree with a few in here that lapping modern barrels isn't necessary unless you want to get it as close to match grade as possible but you might as well get the correct barrel if that is the case. Just do the shoot and clean method and you should be fine. One method is shoot once then clean, shoot 2 then clean, shoot 5 then clean and finally shoot 20/box then clean. I use the bore snake method at the range then the final thorough clean when I get home. That's it, broken in.

[Unclenick]

HiBC has it right. Barrels and barrel making processes are not equal.

Cut rifling: Creates land profiles by removing metal from the reamed bore, one groove at a time. It does not introduce significant stresses into the steel, but it leaves toolmarks. This is how making the bore slightly undersized and lapping it became popular with custom barrel makers.

Button rifling: Swages the grooves into the bore using a carbide button to push into the steel. To make room for some of the displaced metal, the bores are usually slightly oversize to start, but seldom are touched by the button, so the reamer marks normally survive the process. In a bad barrel, this can result in off-center rifling, which I've seen twice in production barrels and which caused keyholing in both cases. It leaves very high outward radial compression stresses around the grooves which have to be relived by heating a rifled barrel blank to about 1100°F for about an hour in a non-oxidizing atmosphere. If that isn't done, contouring the blank usually results in the bore widening where the contour is thinnest, as the stress try to relive themselves. Mass manufacturers often do not relieve the stresses, so if you slug them from both ends, pushing the slugs through feels different, with resistance obvious going from the muzzle toward the breech, but almost none the other way as the bore is gradually widening. I have lapped the breech end of a number of less expensive brand Garand replacement barrels over the years. The almost uniformly were half a thousandth narrower from the lower band contour to the breech end where the contour is heavier. If the barrel is stress-relieved (Douglas does this, for example), then contouring has no impact on the bore's uniformity. It then keeps whatever uniformity the maker gave it.

Broach cut rifling. This is like a hybrid of the above two processes. The broach is a sort of Christmas tree of progressively taller teeth shaped like the groove pattern. It is pushed through like a broach and cuts all the grooves at once. This leaves less stress than button rifling but a bit more than cut rifling by single cutter, and the metal shavings can fail to flush perfectly, leaving longitudinal scratches in places. I'm not aware of anyone in the U.S. doing this currently, but there could be.

Hammer Forging. The barrel starts out as a tube and is hammered by multiple rotating hammers against a hard mandrel that looks a little like a bore casting with rifling shown in negative form, forging the lands to form down into the mandrel. This produces high stresses, but in the opposite direction from button rifling, so it doesn't tend to pull the bore diameter the wrong way. Also, contouring is mostly done during the hammering, so little steel needs removal anyway. Some even like to leave the hammer marks. I have only one such barrel on a gun (a Steyr) but it is very accurate and not bad to clean. I don't actually know if they need to stress-relieve these barrels or not.

In general, you'll find custom cut rifling that has been hand-lapped, as Gail McMillan did it, will see little benefit from any further sort or lapping or break-in, except a tiny bit in the throat cut after the lapping was done. Varmint Al says he runs a patch with Flitz about 50 strokes in such a barrel, and that is his break-in. Only if the barrel still fouls afterward does he repeat with JB and then Flitz again to get it a little smoother. To my mind the jury is out on how important the throat toolmarks are to address.

Lapping or firelapping barrels that are narrower at the breech end of the bore is almost always necessary for peak accuracy to be achieved with them, assuming the rest of the gun (action trued and lugs lapped if needed, and properly bedded) is up to top accuracy.

I feel like I am forever correcting people who suggest lapping is the same as wear from shooting and somehow uses up barrel life. That is flattly untrue and comes from not understanding the differences in the two mechanisms. Throat wear is due heat being unable to penetrate the bore surface steel more than a couple of thousandths of an inch during the time the bullet is in the barrel. This expands the bore surface especially near the throat because that is where the bullet base is when pressure and temperature peak. The steel below that surface (the substrate steel) is stressed by this where the expanded part interfaces with it. When the bullet clears the muzzle and the pressure is gone, the thermal transient front then expands out into the steel, but the stress caused by the initial temperature differential has weakened the grain boundaries in the steel just below the throat surface. This is what results in the alligator skin cracking pattern in a worn throat. Pieces of that skin start to break loose eventually, and that causes the throat to lose symmetry and the asymmetry is what messes up bullet balance during rifling impressing into the bullet. It does that irregularly, with the result the symptom of a shot out barrel is intermittent uncalled fliers that become more frequent as the wear progresses.

Lapping does not cut into lands any faster than it does grooves, so it introduces no asymmetry. The only exception to the cutting speed difference is during bullet entry at the throat due to impressing the rifling into the bullet with abrasive sandwiched in between, so the throat gets a slightly more gradual taper from firelapping. That doesn't hurt anything. Indeed, experimenters with extreme accuracy get reamers made with extra shallow throat angles, feeling the more gradual engraving will help keep the bullet better centered in the bore. But the bottom line with firelapping is it does move a throat forward a little. I have used the military type throat wear gauge on the Garand barrels I've firelapped and get about 1 to 1.5 thousandths increase in reading depth afterward, whereas the breech end of the bore itself is growing only half a thousandth in diameter.

Jack Belk, of Remington trigger law suit fame (his book, Unsafe by Design, is t Amazon and is well worth a read to better understand trigger mechanisms) said that while in the army he got the idea he wanted to remove the rifling from a bore to experiment with a smoothbore for some reason. He thought he could do it by lapping it enough. Nope. He worked at it a long time and the bore just gradually got bigger but still had rifling.

G. David Tubb actually takes advantage of the extra throat lapping during bullet engraving to lap away irregular spots in damaged throats with his Final Finish version of firelapping. He claims he has recovered the accuracy of guns with shot out throats and doubled their accuracy life this way. He uses jacketed bullets and full starting loads, which increases the action of that land engraving lapping on the throat.

The bottom line is that wear from shooting tends toward throat asymmetry and lapping tend toward throat symmetry. This is a vitally important distinction.

The objection was made to lapping rounding edges on rifling. I wish it would. According to Boots Obermeyer, part of the whole secret to the long life of 5R rifling (and yes, Mike Rock is the fellow he taught who then underbid him) is that the sides of each land are sloped rather than sharp, and some of the chrome-moly military barrels with this rifling have gone over 10,000 rounds, which is about three times the normal life of a chrome-moly steel .308 barrel. Why the throat is holding up so much longer is probably explained by that contour eliminating the weakest, most vulnerable edge in the rifling, the outside corners of the lands, which get the hottest in the throat and are the weakest part of the standard rifling profile and therefore are the most easily damaged by heat stress. But lapping will dull a land only to the extent of the size of the lapping particles. Rifling gets lapped a little bigger in diameter as a whole, but military specs for .30 call service rifle barrels is .3065"—.3095" for the grooves and 0.2985"-0.3015" for the bore. British competitors used to prefer a .309" groove rifles, claiming to find them more accurate by letting bullets bump up to fill them. I'm thinking they may still have been greasing bullets at the time, so don't read too much into it, but do know that unlike cast bullets, jacketed bullets can expand a little during firing without gas cutting or other balance problems occurring. Besides, many match bullets are actually about half a thousandth oversized the widest place, so you would have some wiggle room there even if they didn't upset to fill a bore under pressure. The point is, the bore being uniform and/or tapering slightly narrower toward the muzzle is preferable to being uneven or tapering wider toward the muzzle. So the slight widening at the breech end isn't necessarily undesireable.

When NECO developed the firelapping process originally, they got the University of San Francisco rifle team to allow them to firelap 27 of their .22 rimfire rifles. They averaged a 15% reduction in group size, with none getting worse. From NECO's description:

Originally Posted by NECO

There have been numerous third-party civilian and military tests of our process, with reported results similar to our own. At least one International Palma team which now regularly laps its barrels with our kits has reported a tenfold increase in the number of shots which can be fired accurately between cleanings, from 20 to 200. Attainable accuracy improvement is dependent upon the overall condition of the firearm, but spectacular improvements are frequently obtained in rifles, including military weapons such as the M1 Garand, and the process is very rewarding in revolvers. There have been varying results, but none negative, with autoloading pistols.

Some of the custom barrel makers say you don't want to make the surface too smooth or fouling will actually be worse. This does not match my experience, nor, apparently, Varmint Al's. The NECO kit goes down to 1200 grit. When firelapping Garand barrels, I counted the number of patches need to get the bore clean and free of copper (turning the patch blue) after every five lapping rounds. It kept getting progressively fewer all the way through the 1200 grit lapping bullet firing, by which time it was taking about six times fewer patches. This is in line with the claim made by the Palma team, above.

One of the reasons firelapping has gotten a bad name in some quarters is that after NECO patented it, Wheeler Engineering decided to ignore the patent and copy the idea; but only approximately. The cost of defending the patent was prohibitive for a small company (about the cost of a house to take it to court, typically), so NECO never did. Then other copycats jumped on board. The problem was that Wheeler copied NECO's abrasive grades but ignored a key factor: the NECO abrasives are laboratory grade. Standard commercial lapping compounds like Wheeler used have a much wider range of particle sizes. This not only makes them cut about half as fast (this from astronomical mirror makers; its due to too much sub-grade size particles packing around the coarser ones and clogging the cutting action), but in the coarsest size used, 220 grit, the largest particles in standard grade compounds are big enough to put some serious gouges in steel. So a number of people with the Wheeler and other copycat kits wound up damaging barrels by the combination of making those scoring scratches and having to shoot more rounds to get the job done. If you are going to use commercial abrasive grades, don't go coarser than 320 grit and be prepared to take 50 shots to get as far as the NECO kit does in 10 to 20).

[HiBC]

Great post,Uncle Nick!
I agree on variance in quality in abrasives. Because of my plastic injection mold experience,I use mold polishing diamond compound. I've forgotten the brand,but its similar to what Gesswein or DME would sell.Its the green one,and it almost seems like they use Crisco for a base.
With a profiler,I could use that stuff with a cast iron lap to cut EDM surface texture off a mold cavity. A 400 to 600 grit stone is faster,more efficient...but sometimes I'd skip getting stone marks .
That green #9 diamond cuts,but it leaves a smooth,grey steel finish that does not appear "scratched" without magnification.

I also spent a fair amount of time running a fine old American Broach machine.
Amazing machine!!Part of it was in a pit under the floor,about an 8 in dia hydraulic ram!
You are absolutely right about chips.They can't really be flushed out by coolant as they are trapped in the gullet of the cutter tooth.

You run into a similar problem as you do when you pack too many chips in the flute of a reamer. Things go bad fast.

A broach is limited in the length of cut it can make by the chip capacity of the tooth gullet.The small diameter of a bore demands very small gullets.
Point? Probably not practical to broach cut rifle barrels,but handgun barrels? Heck,yeah! And its amazingly efficient.

A perfect part for broaching is an AR barrel extension.From a round hole to the splines takes about 3 seconds after you load the part.
But broaching the bolt raceways through a full length bolt action might be right at the limit.
I built a fixture to use common keyway broaches to cut the locking lug mortices through a Rem Hepburn castings. It really worked sweet!

[Unclenick]

Thanks, I was wondering how the chip limit would affect matters, and what you say about pistol barrel lengths being more appropriate makes sense.

[jjmotsch]

Even the best barrel makers Hart, Schilen etc admit they cannot prove any accuracy increase with a "break in" vs No Break in. I would stay away from lapping a barrel.

[Unclenick]

Jjmotsch,

You can't reasonably make the leap of faith that what applies to a custom barrel also applying to a mass produced barrel. The former are usually cut-rifled and hand lapped, leaving nothing significant to be gained from further lapping, while the latter are often button-rifled and not stress-relieved before contouring, and therefore frequently have very rough copper-grabbing bores that are not uniform in diameter all the way through. You have to be careful about extrapolating preferences from one kind of critter to another, as it often doesn't work out.

When I got my first Garand from the DCM back in the 80's, it shot great for rounds 1 through 40, then the groups opened up substantially. It always cost me at least 8 points in the last ten rounds of the 50 round National Match Course, and I had to consider it unusable for an 80 round NRA Highpower match. The problem was rapid and significant copper accumulation in front of the throat that took several hours of cleaning with Sweet's 7.62 (this was before the modern chelating cleaners were available) to get down to bare metal again. After firelapping, I was able to shoot it through three matches on three consecutive days without cleaning, just to see if it could be done. Accuracy was unaffected by the firelapping, and in that case, wasn't even the object of the firelapping exercise in the first place.

[zukiphile]

Originally Posted by Unclenick

HiBC has it right. Barrels and barrel making processes are not equal.
***

I confess that a lot of that was so far beyond my experience that I don't completely understand it, but reading that sort of post is why I come here to read for pleasure.

If I may piggyback with a different barrel break-in question: Green Mountain has a rimfire break-in schedule they send along with a rimfire barrel. Can a rimfire barrel be firelapped?

I don't see how a wax covered lead bullet could possibly take any rough spots off a steel barrel, but I followed the Green Mountain schedule anyway. Yes, the barrel did get more accurate after their 100 round schedule. It also became even more accurate over the next thousand rounds over which it may have gotten nothing more than a dry patch every 100 or 150 rounds. The fellow who has it now uses nothing but a boresnake, and it performs at least as well as when I had it.

Does the use and cleaning of a 22lr barrel take off any sharp edges or are we just smoothing the surface by depositing lead and wax into low spots, like an asphalt patch in a pothole?

Thanks

[HiBC]

Lead certainly is not going to wear the steel in,but that may not be the point.

Folks who are skilled in knife sharpening know what "the burr" is.When you hold your angle and stone the blade to the point where you have met the edge,the steel will feather to a very thin burr.Its not part of your blade bevel.It folds,breaks,and is generally not desirable.Removing that burr is a step in the process. There are various ways to do it.
Some folks use a wine cork,some hard felt,some newspaper.Some just use a different stone stroke.
The steel of the knife will cut a lot of wine cork,but the cork will break off the burr.

IMO,a lot of what "break in" is about is NOT the bore,but the inevitable little burrs of chambering.
With your 22 barrel,maybe,"If it ain't broke,don't fix it" is a plan.

If you feel compelled to experiment,A 22 should be easy.

I suggest looking to DME mold supply ot Gesswein. Lookat grit charts for a grade. I used #9.I don't recall the micron. I suggest about 900 to 1200 grit diamond mold polishing compound. It comes in a little syringe.

The full dia of a 22 lr bullet is the same as the case.Smear a little diamond on some glass .Use another piece of glass to roll a few bullets through the diamond compound,embedding the diamond in the lead.Try not to charge the brass with grit.Wipe off the excess.
I,myself,would not want the bore quite dry,but not wet,either.Off the top of my head,poking a very loose patch or maybe a nylon brush with just a little Hoppes on it would be good.Not wet,just a drop or two.

You can have your fun with not much chance of doing harm.I'd slow down at about 15 or 20 rounds. You actually might do some good on a Green Mountain.

But I will say again,trying to improve on what the barrel maker sent you is a separate issue from removing the micro-burrs left by the chamber reamer.