"Fire" Lapping With a Bore Mop?

R

ricotorpe

Inactive
I have a 308 barrel which fouls badly. There is copper fouling which was in the barrel when purchased new, and it will not come out. I have tried multiple treatments of multiple solvents as well as Brownell's JB Bore Paste.

I have used the bore paste with patches as well as a bore mop.

With my cheap, serviceable bore scope, I can tell that it has helped, but there is still a ton of copper. The worst thing? It has fewer than 50 rounds down it!

I have thought about firelapping, but something else occurred to me: bore mops with pastes made from grease and the gris.

The firelapping kits usually have three or for grits ranging from around 300 to 800 or more. What if I used one boremop for each grit? I could start with a paste made with grease and 300 grit, coat a fresh boremop with it, and start running the mop back and forth from chamber to just short of the crown.

When going to a finer grit, the barrel would have to be cleaned of all the previous grit, and a fresh bore mop would be needed.

A hard question is how many strokes should be used for each grit? I am pretty sure that would mostly depend on how tight the mop is.

Brownells advocates using Kroil and JB Bore Paste on new bores as an initial treatment to quicken the break-in process.


Any thoughts?


https://www.youtube.com/watch?v=JaPzrAfemIE
 
How about no? Think about it. The pliable nature of a bore mop means it will inconsistently polish things. You want consistency.
 
That makes sense. It also just occurred to me that in true firelapping, the amount of pressure between the bullet and the barrel is considerably greater than the pressure between a bore mop and the barrel.
 
Use something like outlets foul out to get it clean , then fire lap the proper way.

Nothing will work until it’s copper free.

David


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David R said:
Use something like outlets foul out to get it clean , then fire lap the proper way.

Nothing will work until it’s copper free.
Click to expand...

You're right. I don't know why I didn't think of that.

I have spent hours on that barrel, and the copper is still there. Is it possible that I have a bad barrel? Or at least one that is just always going to be super-prone to a bit of the old ultra-fouling?

Grrrrr!
 
If you want to get copper out, switch to a real copper solvent. KG12 is the best I've ever used.

There used to be a web page where some guy did test of 7 copper solvents - by weighing bullets before soaking, then soaking in solvent, then weighing after soaking - but that page has disappeared. The clear winner was KG12.
 
I have a Winchester M70 Featherweight in 7x57 that would copper foul so badly that accuracy was gone in less that 20 rounds, and that was on a good day. Sometimes it took as man as three 8 hour sessions working that Sweet's 7.62 that smelled bad. Another short range session and back to the Sweet's. I finally decided to try fire lapping so ordered a NECO kit. Instructions said to do 5 bullets with each grit thoroughly cleaning before going to the next grit. I kind of changed the rules and used cast bullets instead of jacketed. I did three bullets with each grit and used them as if they were jacketed. When they were done I ran 3 more bullets that had been impregnated with JB compound. Then a good cleaning with regular solvent to insure all grits of any kind was left in the rifle. patches felt like the passes were smoother and after a range day what copper found in the bore was easily removed with CR-10. Every once in a while I'll scrub the bore with some JB bore cleaner but not sure if that's really necessary. All I can say is the rifle seems to be more accurate and the bore is a lot easier to clean.
My suggestion, just do the fire lap and get it over with.
Paul B.
 
Doyle & Dufus

Thank you for the product recommendations.

==
Bart B.

I wish your comment about firearms companies not doing what they should weren't true, but you are spot on.
 
I have a 308 barrel which fouls badly. There is copper fouling which was in the barrel when purchased new, and it will not come out. I have tried multiple treatments of multiple solvents as well as Brownell's JB Bore Paste.
Click to expand...

Any thoughts?
Click to expand...

Many years ago we started using 'streaker' bullets; Streaker bullets fowled the barrel. At the time it was believed 'gooping' up the bullets would reduce fowling. And then they got careless with the grease/goop, before it was all over they greased the round and chamber, it made a slide and glide mess. this problem did not go away with time because there was a lot of streaker ammo/bullets left over; and some countries had not started making/using streaker bulleted ammo.

the last article I have found came out in about 1954, it was written as though everyone had forgotten about bullets that streaked the barrel. Even then people woke up in a new world ever morning. The article finished with advise on cleaning, they included the formula and cautions.

To use the stuff requires discipline, I will have to dig to find the article, even then I do not have anyone's permission to share.

Fowling barrels: I have too many barrels put away to put up with a barrel that fowls. If I was going to lap a barrel I would melt lead to make a slug etc. etc. And then there is another way that could cause the strong to get dizzy and the weak to pass out. I will spare you.

F. Guffey
 
Plug the muzzle end with a rubber plug. point muzzle down fill to chamber end with Bore Tech Cooper Remover and let set for 2 days. Drain bore cleaner and dry patch. Recoat with Bore Tech to see if any is left. I have used about every cleaner made and Bore Tech CR is the best I have found.
 
The KG-12 is actually up to the Bore Tech on copper. I've played with both side by side. It just doesn't turn that nice deep cobalt blue that indicates copper has been picked up.

The filled bore will work but generally isn't required. I just use a pump sprayer I got at Walmart's travel section for 99 cents. I point the muzzle down, pump three squirts into the chamber and let it run down to the muzzle. When it gets there, I plug the muzzle and the breech with a silicone stoppers I got from Amazon, then set the gun on a cleaning vice with the muzzle horizontal and turn it upside down fifteen minutes later. That usually does for most of the copper, but really deep copper will take longer.

If you do fill the bore up, realize the copper will be gone before the solution's capacity is consumed, so you want to save that liquid for a future cleaning. It will just be already blue in the case of Cu++ and more orange in the case of KG-12.


Ricotorpe,

The way lead bullet laps work is they get squeezed hardest by the narrowest part of the bore and don't spring back out all the way to rub the loose portions of the bore. This way they preferentially lap metal off the tight spots. That's how they straighten a bore. A bore mop or the Lewis Lead Remover won't be preferential as to where they rub so they will ultimately let you take the rough toolmarks out, but won't straighten tight spots if you have them. Indeed, a bullet of the right hardness (around BHN 11) will tend to lose cutting ability by particles driving deeper into its surface as it goes down the bore, tending to create a bore that is slightly tapered from maybe half a thousandth wider at the breech than at the muzzle. This is best with cast bullets according to a number of sources, but it doesn't seem any better than a straight bore for jacketed bullets. In general, the harder the lapping bullet, the straighter it makes the bore. I've done some with jacketed bullets that came out very straight, indeed.
 
First,forget a bore mop or anything that does not hold a form. You do not want to just wash out the detail of the bore.
Lead lapping as the barrelmakers do,of course,can give excellent results.I think the final touch of craftsmanship at Krieger just might have enough skill requrements that a non mentored first timer DIY job might do as much harm as good.If you mustIIRC the old Clyde Baker 1930's vintage gunsmithing book goes over casting a lead lap in a bore around a tapered brass wood screw attached to the rod.The lap can be tightened by turning the screw.You don't remove the lead lap from the bore till its time to cast another.As someone mentioned,while this is done breech to muzzle,the reversals at the muzzle may cause increased cut,flaring the muzzle. Cutting an inch and recrowning could be necessary.This does not apply to fire lapping

I bought a prefit cheap Brownells barrel once that showed cross the lands toolmarks and button galling in the grooves.It fouled horribly and shot 2 + MOA. I figured I had nothing to lose,so I firelapped it.The project was quite successful
I have some trade experience with honing and lapping parts to fit.
I know when we are sanding a piece of wood we use a progression of grits,from coarse to fine.That makes perfect sense.
But the rules are different when you are trying to lap .
Grit size is measured in screen size. 100 grit has about .010 rocks in it.250 grit has about .004 size rocks in it. 500 grit s about .002 size rocks
.
1000 grit,about .001 grit.


Whether you are lapping a 1911 slide and frame,or a bullet to a bore,each grit size will provide a certain "overcut" . Using the coarsest cut first will give you the greatest clearance first. Lapping scope rngs,I don't use a 1.000 bar. I use a .995 bar. 320 grit gives a pretty good 1.000 bore in the rings with .320 grit. Remember,the way lapping works it some of the size of the grit is embedded in the softer material.In this way,the softer lap drives the grit,and the harder material gets cut. A larger grit on the same size lap will cut a greater clearance. If a 995 bar laps a hole slightly tight with 320 grit,you will get a slightly larger hole with 240 grit.
I hope this illustrates there is a problem with the idea of lapping something like a bullet to bore or a slide to frame progressing from say,240 grit ,320,400,600,etc. The coarsest grit will cut the largest clearances

If you want to lap a 1911 slide to .002 clearance per side...don't start with 240 grit! You might get .003 or .004 per side,and using 800 grit won't put any steel back.

Unless you have bullets (for 30 cal) sized maybe .304 for coarer grit,.306 for medium and 307 or 3075 for fine grit, I'm skeptical of progressive grits
Another thing.The coarser rocks cut their own longitudal grooves.Assuming the next bullet (lap) is engraved by these striations,that lap with finer grit is working the valleys along with the peaks.Generally,when polishing,you want to cross the previous cut marks.You can't do that in a bore.
The way I see it,just do the whole job with your fine grit.Others may disagree.

I understudied a Master Mold and Die finisher in Chicago . One of the standard diamond polishing compounds I used was 9 micron...the Green.

It was the coarser compound,about 1800 grit.Maybe .0006 or so.

It cuts pretty good.Thats the only grit I used. This was a 30-06 barrel.

I used some of my buddy's 30-30 cast bullets. A piece of glass would work,I used a piece of flat ground steel to smear the compound on. I used another piece of flat ground on top,like a sandwich,to roll the grit into the lead.
I called some in the lube grooves a bonus.
I forget if I loaded 20 or 30..

I don't recall the load. It was mild,but it was probably super sonic.

We used fuel oil as lube polishing....till we went for a high mirror finish.Then we used alcohol,and finer grit.

I took a little kerosene to the range.

I did a moist patch wipe between shots.Just one,left it wet. The slurry s your friend,don't worry abut removing it.


That's what I did,it worked for me. Gesswein is one source of green # 9 diamond. I think DME and MSC carry it,too,under polishing and finishing supplies.

You aren't trying to polish out all the low spots. Cut the tooth off the high spots

I can't say I've tried it,but some of the solid copper bullets with grooved bodies look interesting for lapping.,maybe following the lead bullets.
 
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I have a couple older military rifles with "dark" bores (not real bad, but foul easily). I added some commercial grad ammonia to my Outers and scrub with that. I usually go to my "ammoniated" cleaner after I have used some Gunslick or Breakfree foaming bore cleaner, if there is still some copper in the bore. Works for me, just keep it up until the patches no longer come out green...
 
I used a home made foul out. Could not believe the crud that kept coming out. Took a good part of a day to do a 1917 Enfield. Same for my 7.65 Argentine.

Clean before trying to lap.

David
 
Agreed clean before you lap.The copper contamination won't help your lapping job.Your lapping grit will embed in the copper attached to the bore.Sounds like a wreck to me.

I suggest choosing one of the better copper solvents and using it.

BoreTec Eliminator is one option. Its NOT recommended to allow multiple products to come together in your bore. Etching/damage can result.
This would include home brew "add some ammonia" ideas. That might work,but it might bring regret.
I have not used the electrolysis method but its one way that should be very effective.
 
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