Lapping the Barrel with JB bore Paste

[necchi]

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

The Mink Oil I am using is from TOW so it should be fine for my needs

Ok.
Then what's the solvent?
My point isn't to place blame or de-ride you at all,,
Whatever is happening,, shouldn't be happening. Just trying to figure it out,,(?)
Did you fully de-grease and clean the barrel before you shot it the first time? New barrels have a packing grease from the factory that is very near what we use to call cosmoleine made and used for long term storage.
Not being able to load a second shot with a new gun usually doesn't happen,, it does, but it's not typical.
Something is going on, we need to find what it is to help,
It's easy to make mistakes, there's wild information all over the place, and it's just as easy to fix mistakes.
How do you "clean" the barrel after shooting? What do you do after it's clean? What do you do before you shoot again?
Ya gotta be honest.
Grinding/rubbing more of the steel off the rifling grooves with some magic compound mix shouldn't be the answer you need.
You made the post,, How can we help?

 

[French Colonial]

And..... do you have to use a short starter and really pound on it to get it to start. Try a 10 thousands patch a wet lube.

My personal opinion is that the chunk gun mentality has got a lot of shooters trying to tight of a patch and ball combination, a little bit of fouling and now it won't load.

 

[fillwa]

54cal flinter, 530 ball, 010 patch soaking wet with windshield washer fluid (the cheap blue stuff).
Load powder, corn meal, patched ball.
It works for me.

I had to hammer a 530 ball with 015 patch so I tried 010 and it loads smoothly, not loose.

I bench rest tested accuracy using 015 and 010 patch. Difference was not noticeable.

 

[waksupi]

If you can't start a patched ball with thumb pressure, it's too tight.

If you DO firelap a barrel, saturate a patch with fine valve grinding paste, and fire with only around 10-15 grains, just enough to get the ball out of the bore.

The only rifle I ever needed to fire lap was a Judge Ressley barrel. It was still cutting patches after firing 500 rounds. It took around ten shots to do the job.

 

[jambuster]

Necchi
The gun was originally cleaned when new with Carb Cleaner followed by soap and water. When I load a clean bore the ball and patch go right in . I use a short starter but it isn't necessary . If I load a second shot without swabbing the ball and patch will start ok but I will have to hammer the ball down the barrel with the palm of my hand , hitting the knob of my range rod. I had one get stuck about halfway down which I had to pull. I clean between shots with one patch of 70% isopropyl alcohol followed by a dry patch . I have also tried CVA Bore Blaster to clean between shots with the same results.

When using my old TC Renegade and the same combination of powder , patch and ball I can load several shots without cleaning.

When cleaning up I use Dawn and warm water . The fowling comes out very quickly with no crud ring. I then dry the barrel and lubricate with un-cut Balistol.
This is cleaned out with a couple of alcohol patches and a couple of dry patches the next time I go shooting. I have also tried CVA Bore Blaster for this operation as well with the same results.

I have never shot any Goex since it hasn't been available in a few years. I did find a can a while back (fffg) and I could try it. I have also tried Schuetzen with the same results as Graff. My understanding is they are the same product. I use these in my cap and ball guns all the time with no serious fowling issues so I don't think it is the powder.

If you go to Mike Beliveau's web site he had the same problem with his GPR. You can watch his shooting session with the GPR and his fix video. My question was had anybody used JB to lap a barrel or in this case to polish out the micro-burs .

 

[sheriff john]

Sometimes patches are too soft. Pillow ticking rather than commercial cotton pre-cut patches, for example, makes a difference (but may require a smaller ball). Also, if the muzzle isn't crowned properly, patches can be cut by sharp edges on lands which are enlarged as the ball/patch goes through both firing and loading.

False muzzles, relieved rifling at the muzzle? One original heavy-barrel target rifle I have was built that way.

 

[BP Addict]

It would get smoother and shinier! I have 'fire lapped' many a rifle or pistol!

I myself would NEVER use any valve grinding compound as there is a major difference between gringing and polishing. I do use the 2 grades of J&B Bore Paste on any of my 'toys' that may need it, putting it on a grey ScotchBrite if needed to do what the OP wants to do. I also have a supply of 5 different grits of lapping compounds.

I wasn't aware there were two "grades" of J-B. I can only find one.

Walt

 

[Billy Boy]

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.

My experience with the GPR is the best result was with the largest ball (495 vs 490, or 535 vs 530) and a thinner linen patch.

 

[Tenring]

The Crisco Kid could be on to something because I have been using JB and Kroll oil for lube to get things rocken for years and you may need to step up to a more suitable Grit , The barrel needs to be lapped at least 125 to 150 passes to achieve any kind of results respectively saying that is and I have had my share of troubled pipes. I am sure I will be challenged on this and someone will remark but just saying what I have done in the past that has worked for me with different Grits and lap passes without any damage. Good luck and wish you the best…

 

[bang]

.535 and thinner patch with good lube.
I find 70%-75% wax with remaining % of veggie oil cooked together makes a good lube and works well for patches, general lube, waterproofing and overball for revolvers by adding more wax to make it thicker.
Do not lap a new barrel until you have exhausted every other option.
IMHO PRB fit should be near to thumb pressure start. Just enough to leave fabric imprint on pure lead projectile.
Thin patch for shallow grooves, thicker for deep grooves.
My rifles generally use a .010 patch. Can use a .015. I use the .010 the occasionally use a .015 to help push fouling.

 

[necchi]

@jambuster
Sounds like your doing all the right steps.
What are your patches? Pre-cut?
I've some ideas, but I'll hunt down that Beliveau vid and get back to ya (I like Mikes work and support him)
In the mean time try just a spit patch, just pop one in and make it wet,(instead of the Mink oil), then follow up with another spit patch just down once and back (swab)and toss it. That's it, no need for another to "dry" the bore
Ya got a dirty batch of powder, the %70 ISO isn't "wet" enough to cut the fouling,(?)
The idea is to maintain the same amount of fouling with each shot,, by not allowing a second shot to deposit more.

And @bang has a good idea too, it might be your rifle will like 535 better.
All is not lost, we'll get ya through it.

 

[HSmithTX]

My Investarms 54 is also VERY difficult to load after a couple shots, it's moderately difficult to load if you shoot one, dry patch swab and shoot. It shoots really well, so I am going to keep shooting it as is, it never cuts a patch so I will shoot it until it loads easily or not. The bore on mine was lightly corroded full length when I got it, some minor pitting and frosty for maybe 30-40% of the bore. If it didn't shoot really well I would probably try to do something but in my book if it stacks bullets keep doing that and nothing else.

 

[waksupi]

I'm thinking your patch lube is the culprit. Mix up some moose milk and I bet the problem goes away.

 

[chorizo]

Start with this:

https://www.amazon.com/dp/B0063HCP3E?psc=1&ref=ppx_yo2ov_dt_b_product_details
Finish with this:

https://www.amazon.com/dp/B07S3Y9M3K?ref=ppx_yo2ov_dt_b_product_details&th=1
Make sure you use a tight patch while lapping and you protect the muzzle/crown.

 

[Flint62Smoothie]

I wasn't aware there were two "grades" of J-B. I can only find one.

Walt

J-B Bore Bright (Red container) is a ‘fine’ polisher for regular cleaning, whereas J-B Bore Cleaning Compound (Blue) is for heavily fouled bores (or EXCELLENT for MZL barrel ‘smoothing’) that requires a more abrasive formula to clean.

The mix is a proprietary mixture of diatomaceous earth (think volcanic ash & stuff) and ground glass, which is harder than rust, harder than lead or copper, but softer than steel.

 

[TDM]

That’s my understanding too @Flint62Smoothie

 

[Erwan]

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.

I often come across purely American or Anglo-Saxon words and expressions that I don't master...
Can you tell me what exactly you call mink oil? I don't think for a moment that it is really mink oil, which would be far too expensive and rare for the simple lubrication of patches, so I would be very interested to know what exactly this term "mink oil" covers...
As for me, I use ox foot oil and also, sometimes, canola oil...

Thks.

Erwan.

 

[Erwan]

I also use the JB paste in a blue box, good stuff...
What do you think about the mixture of powdered alumina oxide (also called "Diamantine" by analogy with the powder used by diamond knappers) and compound oil: this mixture is used for fines “mirror” polishing by watch/clockmakers, and it that happens I have a box of it almost full...

 

[chorizo]

I often come across purely American or Anglo-Saxon words and expressions that I don't master...
Can you tell me what exactly you call mink oil? I don't think for a moment that it is really mink oil, which would be far too expensive and rare for the simple lubrication of patches, so I would be very interested to know what exactly this term "mink oil" covers...
As for me, I use ox foot oil and also, sometimes, canola oil...

Thks.

Erwan.

Mink oil is just that...rendered mink fat. Used for leather products and cosmetics mostly.

But in some cases it may be just marketing and not have any "mink" in it.

https://en.wikipedia.org/wiki/Mink_oil

 

[BP Addict]

J-B Bore Bright (Red container) is a ‘fine’ polisher for regular cleaning, whereas J-B Bore Cleaning Compound (Blue) is for heavily fouled bores (or EXCELLENT for MZL barrel ‘smoothing’) that requires a more abrasive formula to clean.

The mix is a proprietary mixture of diatomaceous earth (think volcanic ash & stuff) and ground glass, which is harder than rust, harder than lead or copper, but softer than steel.

The funny thing is it said it's proprietary to Brownell's and they only list the one in my photo (Bore Cleaning Compound).

Thanks!

Walt