What is fire laping and lapping the lugs and how is this done? I understand the idea behind them but don't really know how they work.

Fire lapping is a means of lapping the barrel by applying abrasive compound to the bullet then firing it through the barrel. In some cases lead bullets are used. In others a jacketed bullet.
In lapping the locking lugs a fine abrasive compound is applied to the locking lugs and the bolt handle worked up and down to achieve perfect contact between the bolt lugs and receiver. Some people use a spring loaded fixture to maintain pressure against the bolt face. Others have their own methods. Lapping is best used as a finishing step. If the lugs are in bad shape or a long ways from contact the lugs and seats should be machined then lapped.
I'm not a fan of fire lapping though many report great results. Regards, Bill.

Yup, fire lapping is considered a last resort prior to tossing a barrel.

Malm

Hey'
I have been told by others,that it isn't required to lap a new barrel.I however,always do this proceedure.I use JB Paste and make a 100 passes,through the barrel.Does it work? I quess so.My barrels clean up pretty easy,and all shoot well.
1geejay
www.shooting-hunting.com

That would depend on the barrel my friend. Some just beg for it, and others, well, they come lapped. If your still pulling copper after a period, then you have to try something. Go easy...

Malm

I have lapped my barrel with JB compound before just because the thing fouled so badly so quick. And that definately made it alot easier to clean now. And it holds its groups for a lot longer now too. But still the thing has a mind of its own. one day a load will shoot great and the next day it is garbage. Personally I want to blame it on Varget because when i have used H4895 the results are always very consistent but not as good as Varget has done in my rifle.

Thanks