Lapping the Barrel with JB bore Paste

[springfield art]

Well I have about 75 rounds through the Lyman GPR and I still cannot load more than one round without swabbing the bore with some solvent . I thought by now I would be seeing some improvement. I watched the polishing video with Scotch Brite pads and that seemed easy enough . However I didn't have any but I did have some JB bore paste. I did 50 strokes with double patches and a good coating of JB . It looks shiny when I point a light down the bore . It will be a couple of weeks before I can give it a try. I tried to search lapping with JB but I didn't find a definitive description and results . I will update when I have results in a week or two.

Like sussex says, valve lapping compound.

 

[64Springer]

Valve lapping compound used on an old Jukar barrel.

 

[BP Addict]

I usually use a three-step process. I start with Valve Grinding Compound from the Autoparts store; 100 strokes or more depending on the damage. I then move on to the JB Bore Paste which seems to be finer; 100 strokes or more. Next comes toothpaste; 100 strokes. I make patches from old jeans. It's very durable during the process.

If it's really bad I may start with a course stainless-steel wool used for scrubbing pots. I've also finished with 0000 Steel wool.

Good Luck!

Walt

 

[Rifleman1776]

I still cannot load more than one round without swabbing the bore with some solvent

That is a puzzlement indeed and an issue, I believe, is not related to the bore needing lapping. It is one of those things where an experienced shooter with you could possibly help correct. You need to (re)examine your powder, ball size and hardness, patch and lube combinations. This game often, really always, needs a lot of trying and experimentation to find what is going to work best for you. Have you tried a simple swabbing with a damp (not wet) patch between shots? That might be all you need to do to solve the problem. "needing" solvent after one shot jest ain't normal.

 

[Sun City]

I've often heard about some folks being able to shoot ALL DAY without wiping and if I make it to heaven.....first thing I intend to do is attempt to get Saint Peter into a conversation and ask him how THOSE FOLKS did that....or at least claim that THEY did! Surely St. Peter knows!!

As for the post of Rifleman 1776 above and a simple wiping with a damp (not wet) patch betwixt shots....what I do is put a patch in my mouth to somewhat dampen it and I wrap it around a plastic brush that fits snuggly into the bore and I run it down and back up! No problem seating the next RB. I'm very leery of using what some call a wet patch because in the past that's when I started having FITP with no ignition! Got to be careful of not getting moisture into the powder seating area!!

 

[French Colonial]

I've often heard about some folks being able to shoot ALL DAY without wiping and if I make it to heaven.....first thing I intend to do is attempt to get Saint Peter into a conversation and ask him how THOSE FOLKS did that....or at least claim that THEY did! Surely St. Peter knows!!

As for the post of Rifleman 1776 above and a simple wiping with a damp (not wet) patch betwixt shots....what I do is put a patch in my mouth to somewhat dampen it and I wrap it around a plastic brush that fits snuggly into the bore and I run it down and back up! No problem seating the next RB. I'm very leery of using what some call a wet patch because in the past that's when I started having FITP with no ignition! Got to be careful of not getting moisture into the powder seating area!!

Blow down the barrel, use a patch/ball combination that does not need a short starter, use a wet patch, spit or other.

Shoot all day without wiping.......what's the problem?

 

[LME]

I have a 54 cal gun. I am using .530 Hornaday balls and I have tried .015" and .018" patches with the same results. I am using mink oil to lubricate the patches and they are thoroughly wetted out. The gun is very accurate. Also the patches look fine when I recover them.

Sounds like your problem is one we all would like to have if your rifle is "very accurate". My thoughts on your problem is a little agravation is bearable if the rifle is accurate.

 

[jambuster]

Just to respond to some of your comments

My load is a Hornaday .530 Round ball
110 grains FFFG Graff Powder
.018" Pillow ticking pre cut patches from Track
CCI , Rem , and or RWS Caps
Mink Oil Lube from Track


My goal was to just get the bore lapped enough so I could shoot 3 to 5 shots without having to swab the bore . Mainly so I could reload the gun if I took a shot hunting. I was able to load two rounds and the ball got stuck on the third round. The second round was tough to load because my delrin rod from Track kept bending and on the third shot I couldn't push it hard enough to get the ball down. I think if I had had my range rod with me I could have seated the ball. I am going to order an aluminium rod for hunting and see if that helps. I used a fine scotch bright when I lapped the barrel and I think I will give it 100 more strokes.

What I have been doing at the range prior to lapping is swabbing the bore with 1 patch of rubbing alcohol followed by a dry patch and then I popped a cap on the nipple to make sure it was dry. Everything worked great.

Just a reminder the gun is very accurate.

what do u guys think

 

[Sun City]

Blow down the barrel, use a patch/ball combination that does not need a short starter, use a wet patch, spit or other.

Shoot all day without wiping.......what's the problem?

The problem is that loose patches and NOT starting with a short starter DOES NOT give me the accuracy I want!

 

[jambuster]

Attached is a picture of the only recovered patch from this weekend ( only fired two shots). I don't know if this says anything but you don't see any rifling marks or much powder burn

 

[LME]

The problem is that loose patches and NOT starting with a short starter DOES NOT give me the accuracy I want!

You are so right! I have never seen a loose loaded rifle shoot well not mine nor my few friends. I don't know how tight it needs to be but all tight loads shoot well.

 

[French Colonial]

You are so right! I have never seen a loose loaded rifle shoot well not mine nor my few friends. I don't know how tight it needs to be but all tight loads shoot well.

Not true
My Jaeger rifle will shoot one hole groups and has done for years, coned muzzle and no short starter.

If you already think it cannot be done, it cannot for you, that does not mean it cannot for the rest of us.

 

[LME]

Not true
My Jaeger rifle will shoot one hole groups and has done for years, coned muzzle and no short starter.

If you already think it cannot be done, it cannot for you, that does not mean it cannot for the rest of us.

I haven't ever seen a real easy to load ball shoot good enough for me and all the other rifles that have been in my shop. It could be that we are talking about two different distances or amount of looseness? If you are satisfied with it thats fine.

 

[64Springer]

You are so right! I have never seen a loose loaded rifle shoot well not mine nor my few friends. I don't know how tight it needs to be but all tight loads shoot well.

You are 100% correct.

Not one of my rifles shoot better with a loose patch/ball combo.

And stiffer lube always works better than some slimy lube.

Resulting in rifles that sound/feel like rifles and not some mouse fart woosh where there's no bore/ball resistance.

 

[Scota@4570]

Lapping is using a lead "lap" that was cast in the bore to carry the abrasive. The work is done with a rod and guide from the breech end. The lap is then charged with grit. I start with 120 grit valve grinding compound. I finish with 320. It takes a couple of new laps for each grit. I then polish with steel wool and flitz or semichrome. I usually end up with a blister in my palm. The amount of material taken is less than 0.001" Real lapping will even out tight and loose spots and a choke can be created.

Polishing the bore from the muzzle with various abrasives on soft carriers in not lapping. That is not to say there is anything wrong with it. Lapping is the wrong word for the job though. It is polishing.

 

[French Colonial]

I haven't ever seen a real easy to load ball shoot good enough for me and all the other rifles that have been in my shop. It could be that we are talking about two different distances or amount of looseness? If you are satisfied with it thats fine.

I don't know, one hole groups are good for most people....

 

[Greenjoytj]

Just to respond to some of your comments

My load is a Hornaday .530 Round ball
110 grains FFFG Graff Powder
.018" Pillow ticking pre cut patches from Track
CCI , Rem , and or RWS Caps
Mink Oil Lube from Track

i think using 110 grs with a ball that only weight about 230 grs. is way too much powder, cut back to 85 grs.
A large amount of black powder stays in the barrel as fouling, so load less and make less fouling.

I don't think there is enough lube present after the first shot to keep the amount residual fouling your load creates and leaves behind is soft enough to be pushed on down the second loading.

I use a mink oil lubed 58 caliber wad between patch and powder.
The larger 58 cal wad fits tighter holds more lube and I sure it friction bonds to the bottom of the patch for grip and assists in taking the rifling to insure rotation of the ball.

In my GPR 54 I use a .535" ball and pillow ticking lubed felt wad 85 grs of 2fg.
When I was selecting ball size I tried both .530" and .535".
Only the larger ball created weave marks embossed all the way around the ball in heavy and light embossed patch weave marks.
Even a .535" ball is smaller than the distance across the lands so something else need to help the ball take the rifling to get the spin happening.

 

[French Colonial]

So, here is a picture of a typical target for my Jaeger that is 40 years old, this rifle used to win matches for me on a regular basis and has pretty much always shot this way. I did a lot of load development when it was new and have never varied since.

Getz barrel, coned, no short starter. I might add that this was one of the first round bottom rifling barrels I ever saw.

 

[LME]

Lapping is using a lead "lap" that was cast in the bore to carry the abrasive. The work is done with a rod and guide from the breech end. The lap is then charged with grit. I start with 120 grit valve grinding compound. I finish with 320. It takes a couple of new laps for each grit. I then polish with steel wool and flitz or semichrome. I usually end up with a blister in my palm. The amount of material taken is less than 0.001" Real lapping will even out tight and loose spots and a choke can be created.

Polishing the bore from the muzzle with various abrasives on soft carriers in not lapping. That is not to say there is anything wrong with it. Lapping is the wrong word for the job though. It is polishing.

Yes, by definition you are right a lead plug with an abrasive of some sort attached to a rod is correct. What has happened to the pure definition has been tainted with the word polishing. Like the word cool was. It got another meaning added on. There are few that even know the procedure to lapping a barrel. I would never lap a barrel with the lead plug If I could do something else to cure the rifles problem. It is time consuming, dangerous and nasty if you are not set up properly and a lot of the time it doesn't improve the rifles accuracy much!

 

[Scota@4570]

My result with lead lapping has been excellent. Most modern barrels are rough. They have tight and loose spots. They have annular tool marks on the lands. Lead lapping to a fine finish fixes all of these problems. The resulting barrel is a pleasure to load. The accuracy has been universally improved for me. Next time I do one I will document the process. It is not hard, just a lot of work.