bore lapping

Discussion in 'Rifle Talk' started by midwayman1, Sep 20, 2004.

  1. midwayman1

    midwayman1 Member

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    What is the deal with bore lapping?? from what I understand, it means smoothing out the irregularities in the bore, right? What is the process of hand lapping? what about the tubbs lapping bullets? Is lapping really worth it, how much does really help?

    thanks
     
  2. Drop-Shot

    Drop-Shot Super Member

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    Hi midwayman,I for 1 lapp the bore on all fire arms I own,even pistols.If you can talk a gunsmith to show you with a boroscope,the inside of your rifle barrel,you will be amazed at the grooves in the barrel.Even after several boxes of ammo I noticed that my ruger's and remington's took longer to clean than my weatherby.The boroscope showed me why.the grooves looked like crators and hills.To see if your rifle would be a good canidate for bore lapping,push a cotten ball through the barrel and look for pieces of cotten hung up on rough spots.All high dollar rifles have a hand lapping process before leaving the factory,as well as custon guns.I don't do it for accuracy although in theory a lapped barrel should be more efficient at sending the bullet at a constant rate,I however do it for cleaning purposes.All my guns clean easily and fast due to slick barrels.I have noticed older rifles have a smoother bore than newer ones although I only looked at a few different rifles.Drop-Shot
     

  3. midwayman1

    midwayman1 Member

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    what is your opinion on "tubbs bore lapping bullets? I have heard both good and bad on these, does anyone here reccomend them?
     
  4. Drop-Shot

    Drop-Shot Super Member

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    The ones I have seen do a good job as long as the abrasive stays on the treated bullet.Recovered abrasive coated bullets have very little abrasives left on the bullet.I have heard that the first part of the barrel gets the most lapping and I know that throat buildup is the worst,so I'm still saying fire lapping beats nothing,but hand lapping is still the best,it's alot of work and requires a rifle vise,good cleaning rod,and abrasive kit,and alot of time and effort,but it's nice to know I have a sako or weatherby like finish inside my rifle barrel and cleans in a snap.I use a bore cleaner,MPRO-7 and let it soak,then run a couple of patches through and then a final light oiled patch through and I'm done,not like before at all.Drop-Shot
     
  5. midwayman1

    midwayman1 Member

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    I have heard that lapping can actually mess up the rifling in the barrel, is this true? Does your accuracy improve after you lap your barrel? Can you explain the process of hand-lapping? Thanks again.
     
  6. Drop-Shot

    Drop-Shot Super Member

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    No problem midwayman,put your rifle in a rifle vise up side down if not a bolt action,if bolt action straight up.You will never wear out the rifleing with hand lapping.Get a kit from midway or one of the wholesale outlets.Brownells has a great selection.Use a stiff 1 piece rod and put a bore bristle brush a little under size of the barrel,wrap a cleaning patct around the bristle brush,you then add course bore lapping paste to cleaning patch,if bolt action start from reciever,if lever or semi-auto start from the muzzel but use a bore guide,they are cheap and will help center the job.With some force, but super tight where the rod is binding is too much,use less cleaning patch to proper size the bore.Stroke down and back and thats 1,stroke 75 times,add more paste if needed after 10 or so strokes,you will feel the grit.Clean the course off and re-wrap with new cleaning patch and use medieum for 50 strokes,clean and switch to fine,25 strokes,clean well and then use flitz polish and stroke 25 times reapplying flitz polish every 5 strokes.Clean the rifle and very light oil,try to get all oil out as much as you can.Push a cotten ball slowly through the bore and remove from the end,use a borelight to look for rough spots,cotten will hang up on rough spots and will tell you if the procedure needs to be repeated,about 50% of the time it will need to be lapped again.It's time consuming and enjoyable.If done correctly the gun should be more accurate but most of all you will be able to clean the gun faster due to the slick barrel.All custom rifles and all sako's and high end weatherbys are hand lapped before sent out.You want be sorry even if the accuracy don't improve all that much,but in theory a lapped barrel causes less friction than factory barrels and should be more accurate,but the shooter has to do his part.Drop-Shot
     
  7. Drop-Shot

    Drop-Shot Super Member

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    Sorry but I remmembered alot of folks use lever guns and semi-autos,turn them upside down to keep grit out of the action,if bolt action mag don't come out,you may want to turn it upside down also_On lever guns I put the reciever end full of cotten rags to keep the grit away from the reciever race ways.Clean gun well,I use a bore cleaner like gunscruber and an old tooth brush to clean the reciever wellA gunsmith walked me through the procedure the first time,I went home and did it by myself to all my guns.If you have any questions,just ask.Look under gunsmithing to hear gundoc's post that said you can't ruin the barrel by hand lapping.Some barrels on the same make can be better or worse.To check if your gun has any rough spot,just clean all oil out of the gun and push a cotten ball through the bore and look with a bore light for pieces of cotten hung up in the barrel.If you don't get all the oil out the cotten will slip through the rough spots and not leave a snag of cotten.Good luck.Drop-Shot