What is the difference between hand lapping and fire lapping?
Is hand lapping just pushing several bullets with lapping compound imbedded through the bore from the chamber to muzzle and fire lapping shooting the same bullets at a slow speed? If so, it would seem hand lapping would be better since you could feel the tight spots being worked out and fouling would not be a problem. What is the advantage and disadvantages of each method?

Hand lapping isn't just pushing bullets through the barrel by hand. It's casting a lap in place, working that lap back and forth through the barrel, and tightening the lap as it needs it. then you melting it off, clean the barrel, and start over with the fine polishing grit.

IF there is a tight spot, can work the lap over that one spot until it's no longer tight.

Just pushing a bullet by hand through the barrel would take a long time...without the driving gas behind the bullet, it wouldn't expand...would take the dieameter of the tight spot and stay that diameter for the rest of the trip down the barrel.

Reserve the hand lapping for the really nasty barrels...is a lot mroe morek, but can be selective. For general smoothing, will fire-lap only when a barrel has shown a decided tendecnty to collect fouling and degrade accuracy...many I just leave alone.

True, you can do some fine work with hand-lapping, if you are skilled. That's how many bench-rest and other highly accurate barrels are finished.

Firelapping isn't as selective, but it's certainly easier, and possibly more trouble-free for some folks.

Unless one is experienced with hand-lapping a barrel, or has someone coaching who is experienced, it is one of the easiest ways to ruin an otherwise good barrel! Done right it works very very well, and has for generations. Done wrong is a recipe for disaster.

In hand lapping, you use a poured lap skag and run it back and forth through the barrel, and the propensity is great for that lap skag to become loose in the bore from the lapping action. If that happens, it is VERY easy to round-off the otherwise square shoulders and faces of the lands in a rifled bore. Hence a ruined barrel for all intents and purposes.

Enter fire-lapping. Each time you fire (at low, airgun velocities) a lapping bullet, it is a fresh lap skag, if you will, precisely fit to the bore, and must only traverse the barrel once. As the bore is progressively releived of tight spots, of course each new lapping bullet is a perfect fit, as it is fresh, and formed to perfectly conform to the barrel configuration. As such, there is virtually zero chance of rounding off rifling, nor lapping a "loose spot" into the bore.

Fire-lapping is by far the most fool-proof method, to my knowlege, to lap a barrel for the average shooter/handloader.

Good question, thanks for posting it!

God Bless,

Fire laping will move the throte out as well. If you have bbl with a 'short' throte it is great.