Paper patching to improve a bore

[greywuuf]

OK I remember a thread from years ago where a member (NoBade?) Had if I recall a .303 that he called the sewer pipe. The thread details his adventures on making it shoot and I beleive he said that the bore was actually improving and being polished a bit.
My particular case is I have a Rolling block carbine that I am trying to make into a walking around woods gun for popping hairs and Ptarmigan and the bore while not shot as it has strong rifling the muzzle is not worn out it ( through a bore scope) looks like it was finely rusted and the tops of the lands are pitted. Which makes it foul super badly.

I wondering if it would be possible to paper patch the 7x57 and maybe get it shooting enough to preserve this old girl without having to re barrel. To that end what would I patch to ? Bore size ...groove size ? This one seems to run a slug out at about .285 ....

[Harter66]

Get a .279 mould and patch it .
I have a good 7mm that delivered most of what I wanted . It was .284 I patched to .285 . So far a core .001-.0015 over bore patched to .001 over groove has worked for me .

I had a stupid run during work up I didn't weigh the cores from the new to me mould . 27-130 fp dropped a 141 gr bullet . That will blow primers on a small case way before you get to max loads for a 130 jacketed load .

[Nobade]

You are thinking of 303 Guy but what you propose will work. 7mm is great for patching as you can use normal 270 bullets and just wrap them. A little JB bore paste used as patch lube will speed up the process. The more you shoot the better the barrel will look.

[pworley1]

Some before and after photos would be great.

[greywuuf]

A before shot of my bore with a cheap bore scope 302762

[HWooldridge]

Might also be able to lap it - whether you go the "fire lap" routine, or pour a lead lap to match the bore and do it by hand.

[ShooterAZ]

I bought a Remington 700 30-06 with a neglected bore (rust and minor pits). I planned on rebarreling it, but tried paper patching it just for the heck of it. I did like Nobade did and used a dab JB Bore paste on the patches. It cleaned it right up, and it shot so well after that that decided not to rebarrel it after all. One word of caution though, those JB Bore coated patches will heat up the barrel like no other. I shot five rounds then touched the barrel...Youch! 20 rounds was all it took to polish that bore like a mirror. Just let it cool a bit between each five rounds. I did the same thing with a sewer pipe Mosin Nagant and got the same results.

[greywuuf]

Thank you for the encouragement, .....looking for my cerrosafe and my calipers ....

[303Guy]

Hi greywuuf. That was me. I've been playing with a different 303 lately, one with a very worn bore. It tapers down to fairly strong rifling from very rounded and shallow rifling at the chamber end. This gun initially gave me MOA at 100m / 110yds. I had developed a load that was just warm enough to disintegrate the patch. After a time it lost accuracy and I found that the bore had polished up to the point where it no longer disintegrated the patch. Well, in storage, it rusted again. Yeah, my bad! Anyway, it has now smoothed up again.

Anyway, there are a few tricks I have recently discovered. I was planning on doing a thread on what I've found but I just haven't gotten a round tuit. Maybe now is a good time to start.

Now that sewer pipe rifle - well, that bore is rough! It had a layer of scale throughout. I never actually got stellar accuracy out of it but I suspect that had little to do with bore condition. I did have one load that shot very accurately but it was a light, subsonic boolit. At about 40 yds I could hit an empty beer can in the center! But with my 194gr patched boolits, any feral pig within range would be in trouble. I was driving those torpedoes at a shade over 2000 fps from it's 14.6 inch barrel. So that a pretty hard thump behind the boolit. But not quite target accuracy. I've go that rifle in the front layer in my overcrowded safe for attention soon.

[greywuuf]

I would love to hear any tricks you might have ....a new thread is fine by me.

[414gates]

I paper patch for a model 70 375H&H of 1946 vintage.

Barrel looks like a corroded cast iron pipe inside, just shinier.

I also do not want to replace the barrel, I want to keep the rifle as is, which is pretty much how it came from the factory, except for the bedding job someone before me did.

I'm not paper patching to improve the bore though, but just so I can shoot cast.

[country gent]

I would think there may be several advantages to this. Paper by itself is abrasive, With jb bore cleaner or other mild abrasives even more so. Unlike hand lapping the "abrasive" only makes the trip in one direction, meaning its at its sharpest at the chamber and is dulling down on its travel. This should not only clean up the bore but shoot the desired taper into the bore.
You might consider even lubing the patch with a very light oil like Jo Jobba oil. A very light coat a drop of oil on fingers wipe and remove with patch. This will help carry crud out with the patch. also consider a light cleaning every 5 rounds fired.

[FrankJD]

Yes, paper is an abrasive, at least 12,000 grit for bond paper types and perhaps 20,000 for the onion paper used to make PPBs.

Another "bbl lapping" process is the "Lee Shaver De-Leading and Lapping Method" ...

Excerpt from “Breaking In a Barrel” by Lee Shaver:

Several years ago, I developed a process for breaking-in barrels for lead
bullet use that eliminated the afternoon of shooting and cleaning with
jacketed bullet. It began because I would occasionally have to get bad
leading out of a barrel for a customer, and when you charge what a
gunsmith must charge to stay in business you don’t want to spend an
afternoon scrubbing the lead out of a customer’s gun. And I’m sure the
customer would rather not pay for said services.

What I learned was that when scrubbing lead out of a barrel, I could run
a tight oily patch through a few times and then take the patch off the
jag. I would then unroll a little 0000 steel wool and cut a piece the size
of the patch. Place that over the patch and then run it all through
together. (The proper fit is when you have to bump the rod a few times
with the palm of your hand to get it started in the bore.) When you
shove that steel wool over a patch through the bore of a badly leaded
barrel, it may sound like paper tearing as the lead is ripped out of the
barrel in a pass or two. I can clean the lead out of the worst barrel in
about ten or fifteen minutes that way, and an average leaded barrel will
be clean in a few strokes.

After using this technique for a while, I began to notice that the rifles
that I was de-leading that way seemed to lead less afterwards, which
got me to thinking. We use fine steel wool on the outside of old guns all
the time to do some cleaning or spot rust removal, and it does not
damage the surface of the steel. It just scrubs it. Which lead me to
consider the fact that we are trying to break in a barrel by smoothing
the surface without cutting, and it seems to me that process would go
much quicker if we used something on the inside of the bore that was
closer to the hardness of the barrel instead of lead or copper. So I
started trying the steel wool and oiled patch technique on new barrels
before shooting them. I use it about as tight as I can get in the bore and
wear out a steel wool pad or two in about 15 minutes, then I go and
shoot the rifle.

How well does it work you might ask? On a few occasions, I have built a
new rifle and taken it to a match without ever having fired the rifle. All
have performed flawlessly in their first match and several times I won
the match or set a record with them. On one occasion, I set a new 300
yard range record with the first 13 shots out of a barrel. This method
has become a service we offer to our customers here in the shop and I
have shared the technique many times with others.

[303Guy]

I have made 'fire lapping' slugs for want of a better word. These things will shoot the rust and rough out the bore in two or three shots. There is a risk though and that is that the slug can seal the bore if it fails to drive through. That would happen in the throat itself most likely. Don't ask how I know. And no, the pressure never leaks out. I never did find the case head .... [smilie=1:

But, take a look at how well they work.
https://i.postimg.cc/YqZRKNnK/Rusted-303-bore-007.jpg (https://postimages.org/)
https://i.postimg.cc/WbKgK295/Pig-Gun-Bore-008.jpg (https://postimages.org/)
https://i.postimg.cc/Qxv1z4F1/MVC-544F.jpg (https://postimages.org/) I did need to cut the barrel back.

And another one.
https://i.postimg.cc/BQkck6rb/MVC-445F.jpg (https://postimages.org/)

https://i.postimg.cc/wMXsST08/MVC-565F.jpg (https://postimages.org/)

The last two grooves get filled with fine valve grinding paste prior to being seated in the neck. The stalk and band up front it to guide the slug in the bore and the secondary bands guide it in the throat taper. I learned to cut small grooves in the bands to allow gas to escape. I also made the secondary guide bands thinner. I'm not sure they are necessary but the front one I'm sure is a good idea.

Anyway, I also tried a less aggressive method. That involves an abrasive behind a patched boolit over a wad and a grits filled case.

https://i.postimg.cc/wjjKNfZX/Fire-Lapping_Pig_Gun_014.jpg (https://postimages.org/)https://i.postimg.cc/R0Wjs3Mq/Fire-Lapping_Pig_Gun_015.jpg (https://postimg.cc/FfQW1HkQ)https://i.postimg.cc/Y26TsBwN/Fire-Lapping_Pig_Gun_017.jpg (https://postimg.cc/QVM6FPCV)

[303Guy]

Here is another barrel I fire-lapped. This is the piece I cut off before starting. This bore does not copper foul - it only shoots jacketeds but very accurate.

https://i.postimg.cc/Y05h9fdJ/TWO-GROOVE_BORE_003.jpg (https://postimages.org/)

This is after fire-lapping although I seem to remember fire-lapping it again after cutting the barrel back.

https://i.postimg.cc/nzw5Lh36/MVC-201F_(2).jpg (https://postimages.org/)

A fired bullet from that barrel (minus the core).

[Milky Duck]

watching this thread with interest...Ive read of fire laping via Nathan Fosters books...... actually got some of the fine sand here to do the job too.......

[303Guy]

Things that can go wrong

https://i.postimg.cc/SKn160Fx/shot-skirt-tails-2.jpg (https://postimages.org/) Gas erosion.

https://i.postimg.cc/TPB7Qkfq/Tailess-Patch.jpg (https://postimages.org/) Trailing edge distortion.

https://i.postimg.cc/qBsbXXYy/DSCF3199.jpg (https://postimg.cc/fkbfMXMR)
Patch not disintegrating.

https://i.postimg.cc/c4TFP1dJ/DSCF3310-1.jpg (https://postimages.org/) Boolit riveting and shearing off a ring of patch.

https://i.postimg.cc/T3wtx8PJ/DSCF3646.jpg (https://postimages.org/)https://i.postimg.cc/k4xcsqjq/DSCF3650.jpg (https://postimages.org/)
Boolit riveting - that's where the above ring came from. That's the ring around the boolit base where the knurling has been wiped out.

The sharp edge of the patch is from the case mouth and the rough edge is where the boolit passed over it against the chamber leade.

https://i.postimg.cc/SRSWG82f/DSCF4030-1.jpg (https://postimages.org/) Here the patching ring clung to the boolit.

https://i.postimg.cc/3x4293RV/RIVITING-DEEP-SEATED-18-2-2205-208-WG-011.jpg (https://postimg.cc/Yv74CKQz) Patch didn't come off at all!

Then there is boolit canting. I'll look for a photo or take a photo if I can't find one.

And then when it works out right.
https://i.postimg.cc/qMY7swwF/214-Pig-Gun-20gr-2205-Dacron.jpg (https://postimages.org/)

https://i.postimg.cc/3JbggkK2/DSCF4039.jpg (https://postimg.cc/gn8XpkL0)
Patch disintegration.

[Milky Duck]

oh so reassuring.......

[greywuuf]

Have not been out to my lathe to make me a bullet sizing die ( I have a nice flat point mold I really want to use ) ....but I do intend to get going on this and actually contribute to my thread before to long.

[kbstenberg]

I know every barrel is different. In generalities how much is the barrel dia. enlarged by lapping?

[HWooldridge]

I know every barrel is different. In generalities how much is the barrel dia. enlarged by lapping?

I work in the machining trade and we occasionally have to pickle rusty items. On very light surface rust, you lose tenths but I’d figure at least .001 lost on a bad bore and it would be more on basket cases.

[kbstenberg]

Thank you HW

[Lead pot]

Some before and after photos would be great.


I can give you a before and after what a PP bullet does to the bore.
Below is a new barrel that has the reamer marks and the second is what it's now after running just short of 25 bricks of primers through it. I number the bricks for the rifle I use the primer in to keep track of the shots fired. I lost count after the previous primer shortage and started using them in different rifles.
Yes paper will polish the bore but it takes many-many shots fired before you see the effects.
I had a very dark bore in a Trapdoor that I fire lapped using 400 grid Clover lapping compound with 10 shots fired using those knurled bullets. The knurling holds the lapping compound well and works fast using black powder loads so the bullet fills the bore and groove fast. But I would use caution fire lapping it will erode the throat if you seat the bullet deep in the case. Done that. :(
I breach seat the bullet at the case mouth doing this and it works fine and after a few shots fired I follow up using 600 or 1000 grid 3-4 shots to polish.


303546303547303548

[450 Fuller]

This is very valuable information. Have been reloading for 50 years, but now in new territory. I work/read with Paul Mathews
book on PP slick boolits. Have a few molds. Going slow because the rifles deserve it: an 1885 original HI Wall SS Winchester in 45-60
along with an early Shiloh Sharps "Old Reliable" in 45 2.1. Have various paper thicknesses I am experimenting with. Both bores are
excellent. Might do some polishing on a 338-06 in a pre-64 Model 70. But it is like navigating a submarine through a minefield.....