Author Topic: lapping to remove rust  (Read 14761 times)

Offline T*O*F

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Re: lapping to remove rust
« Reply #25 on: May 16, 2016, 10:52:22 PM »
Quote
I was able to shoot 8 rounds before feeling the roughness in the bore and a simple brush job cleaned it up
Just so you understand something that your rifle is prone to.  As you fire your rifle, a fouling ring will develop in the approximate area you are experiencing.  Shoving a maxi down the bore will deposit lube on top of the fouling in the grooves.  When you fire the next shot, it will fire lap that area and possibly deposit some lead in it.  It will build up over time and lead to the problem you originally had.  Accuracy will go to he!! if it gets really bad.  I had at least a dozen inlines come into the shop with the same problem, all using maxis or sabots ( which left plastic fouling).  A good soak and scrub solved the problem.  That may have been your problem in the first place and soaking the bore overnite was able to dissolve it.

Tightly patched round balls clean the grooves every time you load.  Maxis only clean the bore and poorly if it isn't a super tight fit
Dave Kanger

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Offline mikeyr

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Re: lapping to remove rust
« Reply #26 on: May 17, 2016, 12:00:46 AM »
guess its time for me to learn to shoot round balls with a patch... Not a joke, I never have.  I got this Hawken back in the 70's and have always shot Maxi's with it.  Now with a Kibler kit on the horizon (few months away) I guess I need to learn how to shoot all over again, life is good if you never stop learning :)

 So I have to get a mold so I can pour some 50cal balls, get some patches and who knows what else I need.

 Either way, I am pretty happy my Hawken cleaned up so nice, I may soak it one more time but I was quite happy to shoot it that many rounds prior to having to brush it out unlike what I had to do in the past, guess 40 years ago someone should have told me how to clean it properly.  Thanks for all the help ! I learned quite a bit and going to learn more now that I am going to re-start the build I started 40 years ago, found all the bits in parents attic over the weekend.  I may start a thread about it so as to not hijack this thread.
...let's finish a rifle I started back in the 70's...

Offline bgf

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Re: lapping to remove rust
« Reply #27 on: May 17, 2016, 01:28:53 AM »
Buy some 490 and 495 balls first, and several patch variations to see what kind of mold you want.  PRB is 10x easier than bullets!

Offline smylee grouch

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Re: lapping to remove rust
« Reply #28 on: May 17, 2016, 02:41:53 AM »
Easier to cast, and shoot with less recoil plus easier on your pocket book.

Offline Gun_Nut_73

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Re: lapping to remove rust
« Reply #29 on: June 01, 2016, 03:37:05 AM »
Is your .50 cal T/C barrel 15/16" across the flats, or 1"?  T/C Hawkens were 15/16" IIRC and T/C Renegades were 1".  I may have a spare T/C Renegade barrel in .50 cal.

Offline mikeyr

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Re: lapping to remove rust
« Reply #30 on: June 02, 2016, 07:47:13 PM »
15/16"

I have been shooting it with patched balls and it seems to be fine, the Maxi-balls hang up about 3/4's of the way down only 2-3" from the powder but patched balls slide right on down and are shooting fine, maybe even a little more accurate than Maxi's for me.  Hard to believe I shot BP for 40 years and never tried patched balls until 2 weeks ago, the store that sold me the hawken in the late 70's sold me a few boxes of Maxi-balls and the mould so I just kept shooting that.

 I would grab a spare barrel just to be safe in the long term but with soaking in evaporust really seems to have saved the barrel, the corrosion is so far down it does not seem to affect accuracy.
...let's finish a rifle I started back in the 70's...

Offline Hungry Horse

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Re: lapping to remove rust
« Reply #31 on: June 02, 2016, 11:37:41 PM »
 If  you are  used shooting Maxi bullets in it, why not fire lap the bore using maxi's rolled in lapping compound. roll them with some downward pressure  between two metal plates to imbed the abrasive material into the slug. Load the gun with about 85 grains of powder, and fire it. Clean the barrel thoroughly and do it again. Its a slow process but it works, and is a lot more fun than casting a lap, and worrying the rough spots out.

    Hungry Horse

Offline Daryl

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Re: lapping to remove rust
« Reply #32 on: June 08, 2016, 01:34:44 AM »
Using less powder, say 40 to 50gr. will cause less of an enlargement at the breech & forward due to less pressure in obturation of the bullet. Too- as the bullet progresses, the compounds degrade and cut or abrade less and less.
Daryl

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Offline mikeyr

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Re: lapping to remove rust
« Reply #33 on: June 08, 2016, 08:59:28 PM »
last 2 messages were both great, I never thought of embedding the compound into a maxi and the lower powder charge is a great idea.
...let's finish a rifle I started back in the 70's...

wet willy

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Re: lapping to remove rust
« Reply #34 on: June 13, 2016, 11:41:04 PM »
as HungryHorse said, fire lapping may benefit your bore.

Process is used by some cartridge shooters on modern steel barrels by using soft, cast bullets rubbed/impregnated with abrasives. Fired at low pressure/velocity appeared to clean up rust pockets and eventually enlarged both the groove and bore diameter, thereby reducing the pitted area left by the rust. It might also slightly round the corners of the pitted areas.

Keep in mind the rust has already caused a pit in the metal, so all you are doing is removing the oxide above the surface, but the pit remains. Polishing is removing the surface around the pit, thus smoothing it's surface appearance by lowering the surrounding surface to that of the pit.

As an anecdote, I've had several  ML and modern cartridge barrels that were visibly pitted and shot well ... and some pitted barrels that didn't. I don't know the magic of this.




Offline Scota4570

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Re: lapping to remove rust
« Reply #35 on: June 15, 2016, 06:18:09 AM »
Fire lapping a ML will result in a flared muzzle. 

Offline Hungry Horse

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Re: lapping to remove rust
« Reply #36 on: June 15, 2016, 05:08:38 PM »
 Fire lapping will not totally remove any deep pitting, but it will remove the sharp edges that tear patches. I have never found fire lapping to overly enlarge the breech area, unless carried to excess. Light charges do no good, because the bullet doesn't obturate enough to give good barrel contact. There are just some barrels that are too far gone to improve, and you will have to make that decision yourself. I have seen fire lapped barrels that became pretty good shooters after some serious neglect. Faster twist barrels seem to benefit more from fire lapping than slow twist barrels, for some reason. I have not experience any enlarged muzzle with fire lapping either. Of course anything is possible if the process is carried to excess.

  Hungry Horse

Offline Daryl

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Re: lapping to remove rust
« Reply #37 on: June 15, 2016, 08:56:47 PM »
  I have not experience any enlarged muzzle with fire lapping either. Of course anything is possible if the process is carried to excess.

  Hungry Horse

Nor have I seen an enlargement at the muzzle through fire-lapping.  Taylor was able to remove an enlargement in a Uberti BP ctg. barrel by firelapping - around 100 rounds, if I remember correctly. The rifle now puts 8 out of 10 into 1 1/2" at 100, shot over a rest of course- aperture sights.
Daryl

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Offline Dphariss

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Re: lapping to remove rust
« Reply #38 on: June 19, 2016, 04:30:21 AM »
Ok, first post and yes I have done a search on this and read everything I could find.  I am getting back into black powder, I started way back in the mid-1970's and moved away from BP.  What got me going back was a rifle I started to build back in the 70's, I got as far as inletting everything and didn't know how to proceed, then met a girl, then had a girl and work along with both girls kept getting in the way, well I found that rifle a month ago  (in attic) and I am going to finish it now, along with a Jim Kibler kit :)

 So here is my question...I have a T/C 50cal Hawken percussion that I bought late 70's ish and shot the heck out of it.  Being a teenager at the time, I didn't always clean it like it should have been. Then I put it away for 20 years and didn't protect it for its long sleep.  I took it shooting a month ago and about 2/3rd's of the way down the barrel is something that grabs the maxiball (never shot patched balls, just Maxi and I poured my own) and gives resistance.  I am assuming its rust.  After 4 or 5 rounds you really have to shove hard to get past that spot, or use a brush and clean it up some.  It has not affected accuracy in any way that I can tell, the rifle is still more accurate than I am.  But I am not sure its safe anymore, I am always worried its going to grab the slug on the way out and make it stick in the barrel.  No amount of brass brushing or solvents seems to make any difference.   I have not tried removing the 40+ year never been removed breech plug, not even sure I could get it out.

 My choice would be a new barrel to drop in but what about lapping the barrel to get rid of the rough spots ? I never have done a barrel refresh but I know the concept and could handle that except for removing the breech plug part.  What is lapping and how is it different ?  I can handle lapping valves on a motor so I going to guess same thing.

I would look into another barrel.
If you used pyrodex in it its probably not even safe anymore and will certainly foul HORRIBLY with BP unless its really smooth. It will likely need more than lapping. The pits can be very deep after 20 years. Probably too deep for lapping
Lapping can take a long time to smooth a good barrel, in this case many, many strokes, perhaps casting several laps. You also need to debreech it and should make a rod guide to screw into the breech threads to keep the rod centered for the hours you are going to spend doing this. You also need a 5/16 diameter rod with REAL bearings in the handle. Preferably a long "T" handle as  well.

Dan
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Offline hanshi

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Re: lapping to remove rust
« Reply #39 on: June 19, 2016, 11:22:02 PM »
Through accident I discovered one of my rifles bore had been compromised.  At the breech it had roughened from rust; and the bore, while not having much rust, was very dark.  I pulled the breech plug and did what I could and improved the rough breech a lot with fine steel wool and ScotchBrite pads.  But the dark bore stayed that way.

I took the rifle to the range and coated the lubed patches with J%B Bore Paste.  I fired a couple of shots with it and then continued shooting as normal.  When I got home and cleaned the rifle the bore was still slightly dark but not nearly like it had been.  It now reflected a fair amount of light like it use to do.  I plan on repeating this process one more time and that should do it.

If the corrosion in the bore is light to moderate, this process will definitely help.  If it's more rusted than that it probably won't help much.
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