I've read a lot about fire lapping a barrell in a number of posts and Marshall's technical manual. I am very satisfied with the accuracy that I get with my Marlins utilizing both hard cast (BTB) and jacketted bullets, so I haven't felt the urge to fire lap my barells. But, I'm just curious, is there a process or procedure for manually lapping a barrell? Are there advantages of manual vs. fire lapping. Just curious...

Thanks,
Dan

Advantages:
1. Can do it at home.
2. works on smoothbore barrels (but usually not choked barrels)
3. Works well on muzzle loading barrels (but need to be bare-barrel, no breech plug).
4. Probably puts a more uniform pressure on the lands and grooves.

Disadvantages:
1. It's more work.
2. If not careful, can bell the ends of the barrel.
3. CAN'T be done right without free access to both ends of the barrel.


set up:

Need to get as close to a bare barrel as you can...will even dismount triggers, sights, etc. This is just becasue it is easier to work this way.

Barrel in a large padded vice horizinatally.

Need a metal rod, sub bore diameter, about 6" LONGER than the barrel AND reciever that might be attached.

Remove the rod. Wrap the end with patching matieral and reinsert from the breech until it just engages rifling. Mark the rod flush with the end of the reciever. THIS MARK TELLS YOU WHEN YOU ARE ABOUT TO PULL THE LAP OUT OF THE RIFLING.

Remove the patching.

Run the rod into the barrel, making it flush with the muzzle. MARK the rod flush with the rear of the metal work. THIS MARK TELLS YOU WHEN YOU ARE IN DANGER OF PUSHING THE LAP OUT OF THE BARREL.

Roughen one end for about 2" with small hacksaw cuts, giving the lap nothces to bit into.

Release agent in muzzle section of the barrel (about 4" of barrel).

Back from the end of the rod with notches about 2", wrap cloth to a TIGHT fit in the bore...then do it again about 2" back from the first wrapping. Grease the cloth wraps. IDea here is that the two wrappings will make sure the rod is centered to the bore.

UNvice the barrel, re-vice it so the barrel points UP.

Run the rod in to the barrel, stopping when the nothced tip is about 1" below flush.

Warm the barrel just to the water-sizzle stage...cast the lap. Are using the barrel as a mold...it will smoke from the grease when the lap is cast. Whne casting, the notched tip shuld be about 1? back from the muzzle...and DO NOT RELY ON THE PATCHING TO HOLD THE ROD IN PLACE. Either clamp it to the reciever at the REAR or prop it up so ti won't shift as the lap is poursed (the clth tends to char a bit a loosen).

Let it cool.

Un-vice the barrel and re-vice it so it's horizontal.

Tap the lap so that about 1/2" sticks out the bore...cut the end flush (only need to trim about 1/4" or less). When you case, some of it flowed to match teh corwn, so thatover bore sized sction needs to go. Just push the lap out until you see clear rifling marks, then trim it.

"Paint" the lap with lapping compound.

Push and pull (remember those marks on the rod...ever push it all the way out of the barel or pull it all the way out at the breech end).

IS OK to push about 1/2 the length of the lap out the muzzle end..and that's where you add new lapping material.

Run the lap all the way out of the barrel...melt it off with torch...remoove rod..clean barrel...start over with a new lap and a differnt grade of lapping compound (or the same grade if the lap loosened before you removed the tight spots).

With the extra long rod, it's nice to work out a good handle for the pushing and pulling you'll be doing. If you don't feel the need for a nice handle, can clamp on very tightly with vice grips...then wrap the vice grips in tape or cloth...but if the vice grips slip, you can have trouble. I prefer to make the rod a day ahead, eeply roughen the end, and simply attache a wooden screwdriver type handle with good 24hour epoxy.
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Have lapped revolver barrels. Need to vice them so that the barrel point DOWN and cast the lap onto the rod by way of the focing cone...tought to work inside the limits of the frame opening, but get creative.. Other than that, the process is the same as above. (although you have more visual control and don't need marks to keep from pushing/pull the lap out).

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Told you it was a lot of work.

ribbonstone,

You're right, this is a lot of work. Many thanks for taking the time to provide the comprehensive explanation. Through the moderators, Marshall's and other great people on this forum, I have been able to do some really good load development and, as mentioned above, don't have an urgent requirement to lap my barrels; however, I have "stored" your input for future reference! By the way, compliments aside to you guys, I still do hold you accountable for my Marlinitis.

Many thanks,
Dan
P.S. I spent a good portion of today loading BTB - .432"-290g LFNGC for my .444. The rest of today was spent catching BIG jack perch through the ice! Hhmmm....good eating!