Bore lapping.

[Harter66]

Yes I know there's a sticky. I've actually read it a couple of times through. Heres the link I gave.

http://castboolits.gunloads.com/showthread.php?17696-Barrel-lappping

This is from another web board forum . They seem pretty sharp at 1st glance but I'm having doubts now as I see more and more of their posts like this.

Question from a new guy w 7 posts
Originally Posted by andybirkle
Do any of you guys lap in a new barrel? If so how do you accomplish the process? Thanks.

Answer from a builder of rifles,vender/sponcer/mod/1st 100 group member of that forum w/over 9000 posts and nearly 10yr on that forum.

Lapping is near impossible for a consumer. Polishing to remove sharp edges and advance break in is fairly easy. Use a brush slightly smaller than the cal. Wrap a patch or 2 around it so it fits tight in the bore but can be moved. Cover the patch with Iosso bore paste. Place the muzzle on the floor to stop the patch from exiting and damaging the crown. Run the patch in the breech end always, full length about 20 strokes.
Clean well after to remove all polishing media. Apply light coat of oil then one dry patch to remove excess oil.


I know the answering guy is in business to sell parts particularly bbls but what the heck?

[oldpapps]

My daddy didn't use the word 'lap' but he told me to always do 'it' and I do what my daddy told me to do. He's been gone 14 years now and I miss him.

OSOK

[Harter66]

I cleaned them all this weekend and to date I've had exactly 2 new rifle bbls. Both were pactched just to be sure they were as slick as they looked and they were. I even lapped a couple of high milage bbls to clean them up and in 1 case to get the taper going the right way .

[gray wolf]

Could be what he meant by difficult was using a lead lap and using that to polish the barrel. I do believe that is a little more difficult for the average shooter to do. One thing I have a little problem with when using the cloth patch method is the cloth patch does not always get the grooves well enough. It seems to do the lands quite well but I always notice the grooves could be a little smoother.

[knifemaker]

It is hard for the average gun owner to lap a barrel the way a barrel maker may do it as it takes a lot of experience and practice to get it right. The methold described above would be easy for a lay person to do and remove any possible small burrs and give a finer polish to the barrel.
I prefer to fire lap a rifle or pistol as it is very simple if you follow the instructions given in the fire lapping kits. I would reccommend using one of the kits for the very first time to gain information on how to do it. After that you can purchase your different grades of polishing compound and use your own cast lead boolits to do the fire lapping.
I had to fire lap a Ruger 44 Blackhawk to remove a one thousand constriction at the barrel-frame junction and it did improve the accuracy. It took about 40 boolits using different grits of compound to complete the firelapping and removing the constriction. I have done one rifle that had a habit of heavy copper fouling when first bought that would decrease in accuracy after about 20-30 rounds fired in it. After the fire lapping that rifle will shoot about 60 rounds before i need to use a copper remover to clean the barrel and get it back to it's 1/2 to 3/4 inch groups at 100 yards.

[detox]

Very fine 0000 steel wool (you heard me) wrapped around loose fitting bronze bore brush will bring a dirty/fouled or rough barrel barrel back to life quickly. I also use Kroil or Hoppes solvent during scubbing. Be very careful around crown area.

[Harter66]

It's intresting he would say its near impossible for the consumer. We do probably several every week.

[jonp]

I'd first try fire lapping. Brownells, numrich and several other places sell kits to do this. I have never had a real need to do it but I don't shoot competition and find my firearmsaccurate enough formy purposes

[longbow]

I have only lapped a couple of barrels but since they shot much better after than before I have to assume I did something right.

I wouldn't say lapping is easy but if you have any mechanical aptitude, it isn't particularly hard.

I cast a boolit or lapping slug, drill it for a rod with a threaded end and shoulder, run the rod through the hole, put a nut on to hold it in place, oil slug and barrel, tap the slug into the barrel with a soft face mallet, run it through the barrel a few times, coat the lapping slug/boolit with valve lapping compound the make full strokes through the barrel feeling for tight spots and working those a bit more and then concentrating more on the breech end and less on muzzle end to make a slight... very slight choke. USE A MUZZLE GUIDE FOR THE ROD! Any rod contact with a grit lined bore would be BAD!

I had tight spots in my Marlin 1894 at roll stamping and dovetails so lapped those out and it made a world of difference to accuracy and eliminating leading. That is a microgroove barrel too.

I lapped a .303 Lee Enfield much the same way except I had to turn the nut down to suit the bore diameter and leave a bit of clearance.

Go slow and easy, and check the bore often.

For minor polishing and smoothing, firelapping may work as well or better. Haven't tried it so I can't say. Since the Marlin had noticeable tight spots I wanted to hand lap that to make sure I removed those tight spots then work the whole bore.

I doubt most barrels would need anything but a polishing if that and the bore brush with patches and bore polishing compound should take care of that. If the barrel is pitted, has rough machining marks or tight spots then lapping may just help and is probably worth while.

Worked for me anyway and wasn't very difficult.

Longbow

[303Guy]

I have restored a rusted 22lr barrel back to life with household abrasive cleaner as well as an air rifle that was leading the bore and tumbling the pellets. I used heat to remove the lead together with steel wool on a bronze welding rod pull through followed by abrasive on the steel wool. After that it would pile the pellets on top of each other.

I've used a more vigorous than normal fire-lipping technique that involves machining a brass slug with bore-ride nose and bands to fit the throat with a groove to hold the abrasive inside the case neck. This can be tricky and if done wrong can jamb the slug in the throat. I have a case drilled through and an extended drill bit for drilling those out. A bit problem occurs when the slug jambs and seals the bore. This happened once and after a few days the pressure was still there! I now create a gas escape groove in the slug. The upside of this is the total rust removal and sharp edge dulling in one fowl swoop! Even into the deepest corners of the rifling. That's how I restored my pig gun into shooting condition although that took more than one slug.