how to remove bore pits

[roundball]

KVRunner just posted this a while ago:

"...Bob Hoyt turned my TC 56 smoothbore into a .62 rifled barrel in three weeks at a cost of $60..."

Give Hoyt a quick call and see...a simple rebore to smooth should not be a lot

 

[Sinner]

You could try using a conical to lapp the bore with some lapping compound:
1. choose a appropriate conical, drill a hole in the center of the front of the conical and screw in your range rod
2. choose a lapping compound
3. get two hard steel plates.
4. put lapping compound on the bottom plate, place the conical on its side on the compound, use the other plate to press and roll the conical so the compound is pressed into the lead.
5. using the range rod, push the conical in and out of the bore.

by using a coarse grit first, and then finer grit, you'll polish both the grooves and lands.
You have to be careful with hones that you don't remove metal from the lands, leaving the grooves untouched. You also need to watch that with the method I described. If your conical is too undersized it will take more off the lands, before it touches the grooves.

 

[ohio ramrod]

A simple way of assuring lapping the groves without over lapping the lands is to use a short lapping slug and take a hacksaw and carefully cut the grooves in the slug larger. Remember the slug is a "miror image" of the barrel. :idunno:

 

[Leatherbark]

Take a 54 caliber ball and squeeze it in a vise to make it fatter than the bore. Pound it into the bore with a mallet. Pull the ball out with your ball puller. Coat the rifling engraved ball with grinding compound and push up and down the bore to grind and smooth out the pits. You will need to change to a finer grit before your done.

When you are finished the lands at least will be smooth and shiny.

The lead lap that Ohio Ramrod speaks of is the Cadillac version of this lapping ball and is more effective. But the ball will get you started.

Bob

 

[nkbj]

:surrender: I have a .54 T/C Hawken 1:48 twist that I purchased with a pitted bore and I am looking for suggestions to get it back into shooting condition.

Recently I've tried fire lapping with silty clay on the patches. I've got plenty right out the front door. It works on smoothing up a bore and it's more fun than other ways I've tried.
I used a minimum amounts of powder to get the ball way down there below where one would normally be.

 

[jdkerstetter]

I agree with you guys here that lapping will smooth the existing bore....remove machining marks, rust scale, etc.

But what am I missing about removing pits? Please explain to me how using a lead lap that is the same diameter as the inside of the bore removes enough metal to no longer have pits.

Lapping removes very little metal, almost immeasureable.

Lapping will probably improve the shootabilty of the barrel but if your desire is to remove pitting then metal must be removed. Pits are subsurface or cavities so the metal around them must be removed to effectively remove the pitting.

The only way I know of that this can effectively be done is to refresh or rebore.

I'm not trying to insult anyone but perhaps if we move this to the gunbuilders' workbench forum we could get some expert opinions.

J.D.

 

[Ken Rummer]

I lapped a .50 cal Investarms with the bullets from Bear Tooth Bullets using their lapping compound and their procedure. All are available from the website.

The bullets are hollow base and the skirt expands to work the bottom of the groove. Bullets are .500 dia. (I also bought lapping bullets for a 54 cal. but the bullets turned out to be .535 so I never shot them.)

Before lapping it shot three round groups of 3.9" at 50 yds. Now it shoots into 1".

I used 2x 5 shot groups with 55gr. Goex 3F. I wiped after each shot and went home to clean the bore after 5 shots. A total of 10 rounds did the job.

 

[jdkerstetter]

Thanks. I was not aware that someone has a fire lapping system for ML.

I am a proponent of lapping as it contributes to accuracy....I just don't see it as a way to remove pitting.

J.D.

 

[nkbj]

Not that the pits will be gone, but you can improve the way the barrels treats patches by fire lapping with grit on patches. It's just making the working surface less hostile.

 

[jdkerstetter]

Agreed. J.D.

 

[lyman.54]

yes I like that idea!!!!!!!!!

 

[lyman.54]

Thanks JD I think it is a good suggestion to move question to gun builder forum. I'll do that.