Lapping an Uberti 1873 Lever - Barrel Spots leading Too Much

[RadarsRUs]

Howdy All, Frequent reader but not a frequent poster here for years. I have an Uberti "Special Sporting Rifle" 24" barreled 1873 Win / case-hardened receiver, etc. in the original .44-40 WCF chambering. I absolutely Love this thing and shoot it often with cast bullets. The 200 gr. bullets are .429" and commercial "magma-type" slight-bevel base cast with a hard red lube in them. They are medium hardness that I buy at .430 and side-down so nice and uniform. Bullets are good and tight fit. Probably have 400-500 rounds through it with Unique, BE and (Courtesy of Savvy Jack he REAL Jewel in powders for this thing!) Alliant Reloder-7. Max Velocity is nearing 1,400 fps. with RL-7 H-V loads, but usually 1,000-1,200 for just plinking around with Unique.
Problem is in bore exactly 3" forward of the beginning of rifling. There is a "Loose" spot for about 1" that is a real lead grabber where it "Returns to Regular Bore Diameter" as bullet travels. Also the bore is no super-star with respect to visible tooling and reamer marks. I have one of those brilliant Teslong fiber optic bore-scopes and can see every little detail of the steel with excellent clarity.
I ran 6 LBT Lapping compound bullets through that smoothed up the throat a bit and removed all the tooling roughness off of the beginning of the Lands. Now lands start nice and shiny. Going up the bore I don't see any softening of the very sharp rifling edges or this strange little Loose Spot that has some nasty tooling in fwd. edge. I think i was using 2-3gr. of BE to pop them out.
Question for the gang here is how many LBT Grit rolled Beartooth Lappers do you think I will need to make a noticeable cutting-down of some of the Sharp Edges 2/3 way up the barrel and "soften the Transition out of that little "balloon spot" in bore?? I guess it goes to "How Hard do you think Uberti's Barrel Steel Is"??

Thanks everybody and standing by. Steve in E. Florida

[Der Gebirgsjager]

Have you considered hand lapping? A lead slug on a dowel or rod where, once it becomes engraved with the rifling, pull it back and forth over the rough area.

DG

[RadarsRUs]

I would really rather not get onto having to casting a lapp and all that good stuff. I think also a lot easier to wreck the barrel if you are hand-lapping, no?

[hithard]

Hand lap. You'll be able to feel everything and keep the polishing where you need it and not remove material where you don't want to.

[RadarsRUs]

The Deep Blue-Black on the Octagonal barrel is flawless. I am also only able to approach cleaning (and would be case for lapping too) from the crowned Muzzle.
If I hurt that beautiful deep finish because of Heat when making Lapp I would never forgive myself. Also cranking away that hard from the muzzle of hi-finish barrel is not a nice prospect to keep this thing in 99% shape.

[Bent Ramrod]

I generally charge 50 cast boolits at a time with Clover 320, rolling them between steel strips. I go to the range with a full powder measure (set to the minimum charge of powder that gets the coated boolit out of the barrel), primers, a re/decapper, tweezers, a dowel, cleaning rod/brush/patches/solvent, rags, and a box of the loads that so far work best in the gun.

I setup a target and fire a 5-shot group at 50 yards with the “good” load, brush and clean the barrel. That is the “before” reference group.

I tweeze an abrasive coated boolit into the chamber, push it in as far as it goes with the dowel, prime and load an empty shell, insert it into the chamber and fire. (I shoot at the target, just for curiosity but this isn’t critical.) I extract the case, wipe it off with a rag, wipe the breech off (in case some lapping compound has strayed) deprime, reprime, and charge. Another abrasive boolit is put into the barrel as before, followed by the loaded shell, and another shot taken.

I do five of these, loading the single shell over and over, then wipe the gun down and clean and brush the barrel thoroughly. Then I do another five lapping shots, and clean again.

Somewhere along the way, maybe 25 shots, I check progress with another 5-shot group from the “good” load, brush, clean, and do more lapping shots. Part of the evaluation is the group on target, but check for leading coming out of the barrel on cleaning as well. Then back to the firing of the lapping shots.

You will get leading from the abrasive charged boolits, and the lead will build up at precisely those areas of the barrel that most need smoothing out, protecting them from the abrasive action. Hence the cleaning. As you continue to fire, this leading tends to diminish, but I always clean every five shots. The barrel will get noticeably warm from the friction, and will stay warm for ten shots or so of your group checking load. Some of the abrasive compound apparently embeds in the barrel steel, but it goes away after a shooting session.

I usually do 50 lapping shots a session, because it is a fair amount of work. Depending on the groups obtained, I might do a hundred or more shots over several sessions. Eventually there comes the point where a judgement call is necessary: are groups and cleaning continuing to improve, or is this as good as it’s going to get? At that point I stop, clean the gun thoroughly, scrap the shell, and call the job done.

I have lapped barrels by hand. The advantage there is that you can feel tight spots in the barrel and give them more attention, but the setup; casting and stops and such, is a lot more work than the fire lapping. It’s also a lot more complicated checking your progress by shooting groups, as the barrel has to be put back on the rifle.

If you do lap by hand, you will get a perspective on what hand lapping (or fire lapping) is about, and you can skip past all the Internet posts with their dire warnings about “enlarging the bore,” “shooting out the throat,” etc. Each shot is one lapping stroke, and I would have to say that watching a video of somebody turning a .30 caliber into a .303 caliber would likely take a week of 8-hour days, at least. Likewise, people who innovate the process with jacketed bullets, or machine-gun a few boxes of lapping rounds through their gun, are the ones most likely to get on the horn and announce that fire lapping doesn’t work. The method Merrill Martin developed and published in Precision Shooting does work. And I’ve never made a barrel worse by doing this procedure either.

I’ve never lapped a barrel that already shoots 1-1/4 MOA consistently in hopes of getting a “hummer” barrel out of it. The barrels I’ve lapped have all been frosty, scuzzy, pitted or didn’t shoot right from the beginning. I’ve never done a lever action repeater either; you might need a Delrin cleaning rod to get around those corners, and definitely extra cleaning of the mechanism.

And then, there is the unanswered question: how does your gun shoot now? I had a .22 once with a bulge halfway down the barrel that shot as well as any other sporting .22. A few flecks of lead at the bad spot didn’t build up or cause problems. Like the WWII ads used to say, “Is This Trip REALLY Necessary?”

[RadarsRUs]

HI "Bent Ramrod" (funny),

Thank you very much for that detailed description of your experience on this stuff. Regrettably, my outdoor range absolutely Forbids Any "reloading activity" of Any Sort on the property. It is a great place to shoot with 6 ranges, but the Lawyer Factor has unfortunately kicked-in big time since about 6-7 years ago. Oh Well.

Hearing you talk about the Number of (25) shots you frequently run through (with cleaning at 5 rnd intervals) before "Checking for Progress" gives me more comfort to just go ahead and Run 15-20 loaded "rolled-grit" bullets / low Tite-Group charges with confidence that I won't suddenly find that I have no more bore...;-)

OK, off to the garage for some in-home "cowboy action shooting" into the towel stacks and See What We End Up With...

THANKS and I will report back to the gang here.

[littlejack]

Seeing as you size down the boolit anyway, have you thought about seating a plain base gas check on them while you're sizing. I dont use that particular size, but maybe one of the members would be willing to send you a couple dozen to try out?