Serious Fire-lapping my way

[303Guy]

Following up from my constricted bore Lee Enfield which also happens to be a bit rusty on the inside.

The model.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-565F-1.jpg

The beast as I made it. (Goodsteel, if you're watching, I couldn't see the burrs! :roll: - you can't be too sure who's watching your b-ups. :mrgreen:)
http://i388.photobucket.com/albums/oo327/303Guy/Fire-lapping189620gr2205WG003.jpg

Loaded (the grit is visible in front of the mouth. It's not supposed to be there but it won't get into the works so I left it). The vent groove is visible - which wasn't needed this time.
http://i388.photobucket.com/albums/oo327/303Guy/Fire-lapping189620gr2205WG006.jpg

The aftermath. Here one can see the deepest recesses of the bore got hit. (Up to the restriction, that is).
http://i388.photobucket.com/albums/oo327/303Guy/Fire-lapping189620gr2205WG011.jpg

[leftiye]

Hope you're using a FINE grit abrasive. I'd expect solid brass to really make it cut. How did the bore look after that?

[303Guy]

Not a touch at the muzzle end. It does look a bit shinier from the breach end. I'm about to make and fire another one if I can find a piece of brass somewhere.

I'm using 400 grit valve grinding paste.

[btroj]

I still think a nice, soft lead bullet is the way to go for lapping. Cheap, we know how to make them, and they work. I also like the idea of having a soft bullet that won't bump back up after finding a tight spot.
You have a very interesting concept. Keep up informed on how it works. I just wish I had a lathe, and the knowledge to use it.

[largom]

Interesting concept but I think I will stick to lead boolits for fire-lapping. Afraid this might bulge a barrel and or create excessive pressures.

Larry

[dragonrider]

I'm with Btroj, a lead boolit is the only thing to use when firelapping a barrel. If one is going to make something other than a boolit, of some other material be it brass, aluminum or something else, it should be useful for way more than one shot or it just isn't worth making. I just firelapped a 30 Herrret barrel for my Contender this last weekend, did 32 rounds, 16 with 250 grit and 16 with 500. Barrel looks terrific but have not shot for accuracy yet. Prior to lapping it would not shoot anything less that 6 inches at 50 yards. Hoping for better now.

[303Guy]

It's not intended for more than one or two shots (one each). The idea was to get rust out of bores. I found that lead didn't do it. This thing, being 'hard' kept the abrasive into the corners all the way through the bore, providing there was no constriction which I now have it it doesn't lap the bore past that point.

It won't bulge the barrel or cause high pressure but if not done right it can jamb in the throat. The working band at the rear mustn't be too long or should have grooves cut in it to allow it to cut into the bore. The abrasive carrying groove needs to be reasonably large so as to replenish the grit as it passes down the bore. I also use a fibrous filler like wheat bran to wipe out the bore behind the 'slug'.

The charge I used with this last one was 20gr 4227 with the case filled with wheat germ.

The nose guide bit must fit the bore and the slug itself must enter the throat so the base does not get pushed back into the case. If it cants on firing, it'll jamb. I know these things because .... [smilie=1: That's why it has that stalk with the bore guide on the end and those narrow bands that snugly fit the throat.

A prerequisite when attempting this trick is to have a case drilled out as an extended drill guide in case one gets stuck. Once drilled through they come out easily but they won't come out by just knocking them. Once they've entered the bore there's no problem. They must also have a vent groove or two on the front bands.

This trick will remove rust without taking more material from the lands than the grooves. It is a pain making them but worth it to get that rust out. It also removes the sharp edges from the rust pits which is why I like two of them.

[303Guy]

I'm with Btroj, a lead boolit is the only thing to use when firelapping a barrel.Might I ask how you folks do it? I know need to proceed to lead boolit treatment.

I have a paper patch trick but that will 'scrub' the bore without concentrating on tight spots. The abrasive is loaded as a wad behind the boolit. That one is for smoothing the bore, not lapping it as such.

[btroj]

I cast so soft, like BHN 8 to 10 bullets. They need to be a bit over bore size. Long body, no bore ride now is best. The RanchDog style bullets work great.
I use a 1.5 inch by 6 inch piece of steel on the bench. It some 320 grit Clover brand abrasive on the plate and spread out a bit. Place a couple bullets on the plate so you can roll the the length of the plate. Using another similar piece of steel I press down HARD and roll back and forth. May take as long as 30 seconds to a minute. Key is to embed the grit into the surface of the unsized bullets.
Once the bullet is embedded well I set the bullets aside.
I use fired cases that are reprised without sizing the neck if possible, we only want the bullet to stay in place in the neck. Load oer a very small charge of powder, you only need to get the bullet out of the barrel. I always fire into a berm so I can see the bullet impact, that is Howe know it left the barrel.
I fire maybe 10 or 15 then stop and clean the barrel, action, and chamber well. Runa slug thru the barrel. If it seems to need more then I repeat the process. Ideally you only see a bit of cleaning up of the bore at the muzzle.
The reason to use soft bullets is so they stay sized down if the hot a tight spot. Soft lead won't spring back. This will, over time, remove tight spots Ina barrel.

I have used just this system on a few guns. It takes time but it sure works.

[303Guy]

Thanks. Does it open up the throat much? This rifle throat is a little tight anyway or more correctly, short.

[dragonrider]

For my Herret I use a 311041 because I wanted as much bearing surface as could get and sized .002 big. I roled the boolit in valve rinding compound between two pieces of steel pressing firmly to embed the grit well. 1.7 grains of red dot and the boolit barely made it 30 yards to bounce of the plywood backstop. 16 rounds with 250 grit and 16 with 500 grit. When I started the barrel was very clean but not shinny and smooth, now it is very shinney and appears to verry smooth but I have not shot it yet to see if it has improved at all. Hopefully this week.

[303Guy]

dragonrider, did your bore have any known restrictions or reverse taper? If lead boolit fire-lapping doesn't cut the lands more than the grooves then I'm in.

I have a modified case which I filled with epoxy then bored out the insides parallel. This should allow me to seat real deep for a long bearing surface.

Because my objective is to shoot paper patch a high polish isn't required so I can lap the bore with 400grit and call it good. The paper itself will polish the bore to a shine. I have found with rough bores that after a while the load needs to be increased to shed the patch at the muzzle so fire-polishing will speed things up I suppose. I like the idea of starting with 250 grit. Would that be course valve grinding compound?

I've given up the idea of having a long barrelled light weight paper patch gun. I've also given up the idea of a long barrelled quite load gun. I'm just going to go with suppressors. Mine are so light and short overhang anyway and I've gotten used to the fat barrel look. They actually point better because they are so prominent in the vision field. I wish you guys could freely use suppressors. They are great and make you want to shoot more.

Anyway, I digress. Back to the brass fire-lapping slug. This is the high tech tool I use for removing stuck slugs. That's 6.8mm drill bit. It clears the bore just nicely. That's for those stuck in the throat. I doubt they'd stick further down.

http://i388.photobucket.com/albums/oo327/303Guy/0012-1.jpg

[btroj]

It could move the throat a bit. I havent really measured it enough to know.

[303Guy]

So obviously no detrimental effects. I'm a 205gr boolit person and for that I need enough throat so as not to have to seat deep. When I tried a boolit that fits this rifle's throat it canted on launch. Plus it was too light at only 160gr.

[curator]

303guy:

The ideal firelapping bullet is air-cooled wheel weight alloy aged about 2 weeks. It should be BHN 11 or 12 but not much harder. As mentioned, harder alloy will spring back and not properly lap out tight spots. Too soft and you will cut more from the throat as well as need to shoot many more lap-slugs to get the results you are after. Lead Bullets Technology (LBT) has a lap kit and good instructions. http://lbtmoulds.com/measurebore.shtml

[303Guy]

Thanks for that, curator.


It cuts aggressively yet smoothly, without excessive throat wear.Exactly what I was wondering about. Proper cast boolit fire-lapping is then the way to go. That's what I'll do.

OK then, my brass fire-lapping slug has its place in leaning out the rust and taking off the sharp edges from the rust pits. It is aggressive and it takes out scale! My pig gun literally had a layer of scale down the length of the 'bore'. It looked like an old water pipe. It now passes a paper patched boolit with considerable velocity (1600fps) and delivers a measure of accuracy. There is no 'rifling skid'. So the slug works but it's not a bore lapping tool. It's a rust removing tool and it can be fired quite hard.

Thanks to you all for your input.

[dragonrider]

No, when I slugged the barrel I did not notice any restrictions or roughness. I did the procedure because not matter the load I could not hit squat with that barrel. I don't know if it helped yet. I need to slug it again.

[nanuk]

I wouldn't worry too much about brass there, 303Guy... some Buulits are made of brass and have far more bearing surface than your tool.

[303Guy]

Yes that's true but mine have a broad base and carry a lot of grit and need quite a thump to get them going. They also need to be a little over groove diameter to ensure they cut into the deepest recesses. I'm thinking of drilling a tiny hole down the centre to guarantee that a stuck one won't trap the gasses behind it. I had to open a bolt under pressure once! Had the pressure been higher it could have been tricky. That one sealed completely. Others that have stuck leaked out slowly.

[Good Cheer]

Thanks for the info 303guy.
With the 6.5x53R there are no molds in my hands to cast slugs big enough for the .269" grooves. Might try the idea of using paper patched and applying the grinding compound on the patch ahead of the case mouth.

[Char-Gar]

I read the thread and looked at the pics of the gizmo fired down the bore. My only comment is...I sure would not have done that. It may be a whole new and better way to "skin a cat", or not, but I sure would not have done that.

[quasi]

How about using a Jacketed bullet embedded with lapping compound?

[uscra112]

I read the thread and looked at the pics of the gizmo fired down the bore. My only comment is...I sure would not have done that. It may be a whole new and better way to "skin a cat", or not, but I sure would not have done that.

Nor I. If I had a bore that rusty, I'd use the electrolytic method. Can't damage the bore in any way.

[quasi]

I think the bore is already damaged, that's what he is trying to improve on.

[carbine]

Have you fired it? Any improvement?

[nekshot]

303 guy, you out there yet? I am intrigued with your project and interested in your results. LOL at your comments on lifting the bolt with pressure in barrel, kinda gets your attention real quick!

[mikeym1a]

This is really interesting. I, too, would like to know the results of the test firing after the bore cleaning.

[Walter Laich]

Shot 303 a PM and link to this thread. Hope he'll let us know the results

[largom]

How about using a Jacketed bullet embedded with lapping compound?

A jacketed fire-lapping kit is made by David Tubb [benchrest shooter] and sold by Midway. They come in many different calibers. Have used them with great results.

Larry

[303Guy]

Hi guys. My apologies, this thread slipped below my radar. My pig gun is the one I did first this way, followed by a mates rusty bore which a gunsmith had tried to lap by hand. The brass fire-lapping slug cleaned out the rust in the deepest corners of the grooves. I don't know how it shot. My pig gun started out with a layer of scale in the bore. It now looks like a riverbed but the rifling is still defined. It shoots paper patched boolits quite well and at good velocities.

I nearly forgot - I fire-lapped my 'rust textured' two-groove because I couldn't get the rust out the narrow and deep grooves. That rifle shoots j-words very accurately. I have a photo of the bit of barrel I cut off it to ensure the muzzle was sharp and fresh. It has no crown at all and is protected by the muzzle brake/semi-suppressor.

[nekshot]

Good to hear from you again, Been thinking you alot the past few days. Back to guns and this stuff is good therapy!

[303Guy]

Thanks, nekshot. It's going to be a while until I'm back on my feet. Guns and stuff is indeed good therapy and I need a lot of that right now.


If I had a bore that rusty, I'd use the electrolytic method. I think next time I'll go with the electrolytic method first, followed by a brass or aluminum slug. I have two bores that need smoothing and a few lead fire-lapping boolits did little for them. These things are a pain because the correct dimensions need to be determined first. Making them is not difficult but they are only good for one shot but then only one or two are needed usually. My pig gun need more but how many I don't remember. My mates gun only needed one but the rust was already out (mostly).


How about using a Jacketed bullet embedded with lapping compound? Jacketeds would not be able to force the compound into all the recesses. These slugs I make have a large groove filled with compound. One bore I did had deep rust 'pin holes' and the rust got taken out of those near the muzzle. It was shootable with plain cast after the treatment but only at low velocity. But then I suppose the electrolytic method would do the same in which case a good number of lead slugs would probably get the same result if they were large enough.