Can someone out there give me the proper procedure for "hand Lapping" a rifled bore?

I am a hobbyist gunsmith, and I wish to hand lap a bore for a friend.... the barrel is a .223 mini 14 ruger.

I have the barrel removed from the receiver, and it is ready to go.

I do have, on hand, the LaBounty hand lapping compounds in abrasives of "120" "240" and "360"

Thanks, Ridge

Will list the (simplified) steps...but please don't just jump in, will find a text with the steps listed (and illustrated)...know I've seen an article in Handloader in the past.

This assumes you can get unobstructed access to both ends of the barrel.
1. Remove the barreled action from the stock...and remove the bolt (if a bolt gun).
2. Need a once piece steel rod longer than the barrel and action (want to leave a good length grip/handle).
3. Grease the barrel (as a release agent for the molten lead).
4. Cut shallow groves in the rod end..for about 1 1/2" of it's length at the tip. This will give the lap something to bite into on the rod.
5. Run the rod in from the breech.
6. At the muzzle, about 2" back from the tip (and 1/2" back from the shallow groves you cut) wrap with an oil damp patch for a tight fit to the bore.
7. Pull rod back, with the tight fitting patch, until the rod tip is about 1/2" inside the end of the barrel.
8. Pour in molten lead until the barrel is filled (it will only fill to the patch on the rod). The oil damp colth used as a stop will smoke and char, but won't let the lead pass.
9. Once cool enough to deal with, push the rod and lead-blob 1/2 way out the muzzle. NEVER PUSH THE LAP ALL THE WAY OUT OF A BARREL (unless you intend to melt it off and start over).
10. Push the lead lap put of thje bore for about 1/2" and cut the flared end of the lead (it took the shape of the barrel crown) off with a hack saw.
11. Cut or file grooves in the lead lap...these are will hold the lube/grit for lappin.
12. Coat the lap with your selected lapping media..whatever you use, it will need a grease base
13. MARK THE BREECH END OF THE ROD!...this is you forward limit mark...any farther, and you'll push the lap out the front.
14. Measure. Your rearward limit will be the length of the barrel MINUS the CHAMBER. With a 22" barrled.308 as an example....that would be 22" minus 2" for the chamber. With a mark even with the back of the action, pull that lap no more than 20-20.5" back and mark the rod again.
15. Pull the rod through the bore. Want to use slow even pressure so you can feel for any tight spots or looses spots. First time out, two passes would be enough to loosen the lap.
16. NEVER LET THE LAP GET LOOSE...want it tight through out it's travel...loose lap wears rifling unevenly.
17.Tighten the lap once it is easy to push/pull. To do this, let it hang out the muzzle about 1/2", place a smooth flat faced steel bar (or whatever scrap you have that is flat and smooth faced) and tap the metal bar...will upset the lap and increase it's diameter. Prefer the metal bar as it keeps the chances of slipping and denting the barrel crown to a minimum.
18. After a the first two or three passes, tightening should last i or 2 passes...after three tighetneings (step 17), pull it all the way out and melt the lap off.
19. Clean the barrel.
20. Start at step #1 with a finer grade of lapping compound, and go though the process again.

-----
Truth is, I'd much rather start at the BREECH end and lap forward, but with a chambered barrel, that's just not real easy to do. The "best" cuts are when the lap is freash or newly tightened, so this method proably revese tapers the bore a bit...so I'd use it gently. Old-style lapping was done before the barrel was chambered or joined to the action, so they had the option of lapping breech to muzzle.

To do it right, better to de-barrel and cast the lap at the breech.

THE FOLLOWING IS AN EXPLAINATION FO WHY YOU CANNOT LAP FROM BREECH TO MUZZLE IN A CHAMBERED BARRELED ACTION (at least not very easily)...don't take it as instruction, but as THE REASON NOT TO:

Would need to cast a LONG lap if you want to lap from teh breech on any cahmbered barrel...real long....long enough to allow a length of barrel sized lap to still be in the bore after pushing out all of the chamber sized lap...call it a 8" lap.

Push out the chamber section and cut off the chamber casting (in a .308 sized cahmber) to leave 4" still in the bore and 2" crossiong the chamber. Push 2" of bore sized lap out of the chamber (leaving 2" to cross the chamber, and only 2" actaully still in the bore). Groove the 2" outside of the chamber (which is a neat trick as you can't rotate it and it's covered by the action). Won't find pushing and pulling a 6" long abrasive coated lap to be all that easy...in fact, will find it impossible to do by hand.


Reconsider...try the fire lap process...it's about 20X easier and will allow whatever taper that develops to be a "squeeze down" taper.

Boy - that sounds like a lot of work!

Think I'll stick to the BTB lapping kits and not mess around with molten lead, grease, smoldering charred cloths and such! :D

I've done both. Go the fire lapping route. Better and more consistent results in a lot less time UNLESS you have a lot of experience hand lapping, which you don't. Hand lapping was a royal PITA and had quite a learning curve. Fire lapping is so simple with Marshall's handbook that if you can read and follow directions, you can do it and get absolutely excellent results.
The book I had with instructrions for hand-lapping had you repour the lap quite often, I don't remember how often now, and it was just a whole lot of headache. You cannot use the same lap because it wears out much faster than the barrel you are lapping, so you must repour. With fire lapping it is like starting out with a new lap every pass, and that is where the majority of cutting takes place, the first few passes.


By the way, if you fire lap the Mini-14, you need to disable the gas block. I just did my AR-15 so it was a simple matter to pull the gas block off and close off the gas hole with a small piece of ribbon steel and hose clamp. You really do not want lap material being blown back into the action and gas tube, so find some way to disable it, then clean the dickens out of it before returning to full service.

Thanks to all for the replies...... Respectfully, Ridge