Bore lapping

Has anyone lapped their own bore and get good results?

Did you use the Wheeler system?

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=646612

Seems like it would cut a lot of time out of breaking a barrel in. Generally speaking, most of my guns seem to shoot better after 100 to 300 rounds. Always thought that I had found a better load or loaded them better, but it could be the barrel is smoothing out.

Opinions?


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See my posts over on Gunsmithing. It has its uses but I don't use it on new barrels unless something's wrong.

Redial

I have one of those Wheeler kits. I've only used it on one rifle that fouled so badly the original owner sold it. After shooting the rifle, it would take a solid 12 hours total to get all the copper fouling out of the barrel.
The instruction say to shoot ten rounds with each grit, cleaning the barrel and chamber thoroughly. Easier said than done, especially in the chamber.
Having done a little research on "fire lapping", I found that this can prematurely erode the throat of the rifle. Also, as the bullet goes down the barrel, it loses some of it's abrasiveness so the muzzle end gets less treatment that at the chamber end. Just something to think about.
I decided to shoot only five of each grit, rather than the suggested ten. The end result was the bore still copper fouls to some degree, but no more than most rifles with a fairly smooth bore. With selected handloads, it shoots groups in the .375" range at 100 yards. Ain't no way I'm agonna mess with that barrel anymore.
As far as breaking in a barrel, you might want to go the http://www.thefiringline.com and do as earch on gale McMillan the late barrel maker and read his thoughts on barrel break in and fire lapping. It's a long and interesting thread.
Paul B.

I have fire/pressure lapped several barrels. From an Encore 7BR barrel to a 25-06 rifle and a 7mm mag rifle.
The 7mag would actually foul out after 3 rounds. 1st group(3/4") 2nd group(1 1/2") 3rd group(2 1/2"). After fire lapping (30 rounds total) it shoots under 1" even after 10 groups. It cleans up much faster now too.

The 7BR Encore barrel took at least 30 rounds of firelapping and moved the throat out by .180" I learned not to get any abrasive on the ogive. Keep it all on the parallel section of the bullet. I roll my own firelapping bullets with diamond abrasive. It shot well after and was much easier to clean.

The 25-06 took at least 60 firelapping rounds and finally released it's obsessive love for copper. It still fouls but nowhere like it used to.

I think it is a viable process and will continue to do it when necessary. Just keep the abrasive off the ogive, unless you would like a longer throat.
Joe

I do not recommed lapping a barrel already on a complete rifle. The first and last inch are typically scored from change in friction. That is why new handlapped preturned blanks have a cut mark 1" from the end of the tube so they can be cut.

I talked with a gunsmith in Oregon about this once and he said he could do it but there were risks.

Also, so many factory barrels are asymmetrical in the bore, the impression on the lead plug used to handlap a custom barrel will not match the bore throughout its length. You might really screw up the edge of some of the lands.

If the expense wasn't an issue, I'd recommend just getting the barrel replaced.

I lead lap my muzzle loader barrels. These barrels can be really rough. Or sometimes they just have tight spots that you can feel with the lap. The technique may not apply to modern stuff, but it works for me.

What is lead lapping?


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quote:

Originally posted by woods:
What is lead lapping?

Traditional lapping is done by creating a lead plug that fits the bore
as precisely as possible (typically by pouring it in the barrel over a
plug. The lap is removed partially from the barrel and lapping
compound applied. The lap is pushed and pulled through the barrel
until a consistent pressure is felt through the action. It is often
necessary to pull the lar from the barrel and to make a new one, and
it's always necessary to clean when changing grits.

Properly done a lapping will make a barrel consistent to within a few
tenths (.0001"), typically 1/10000". In addition the barrel will be
easier to clean and can run for more shots without bad fouling.

Fire lapping is the lazy man's barrel lapping, and some say that it
does as good a job. Nothing will replace a good custom barrel, but
firelapping will improve most factory barrels and make them easier to
clean and fire more consistent groups.

I have used JB on several barrels.

I only use it on rifles that foul badly or just wont shoot accurately.

I take about three patches and coat thoroughly w/ the JB Bore Paste or Bore Cleaning Compound. If Cleaning from Muzzle, be sure to have a guide. I use the first patch for about 25-50 strokes depending on how the patch holds up. I generally do 25 to 150 passes depending on how bad the barrel is. Then, thoroughly clean the barrel w/ #9 and lightly oil. This process will make a barrel have a mirror shine and can dramatically improve accuracy!

As someone else mentioned, this process can dramatically reduce "Break-in time." The last rifle I did this on was a Savage 16 300WSM and the results were great. That particular rifle went from just average groups to shooting .5-.75" groups regularly.

This process has done amazing results on several muzzleloaders, I recommend at least 200 passes on MLers. I had some MLers that I had just about given up on and as a last result I gave them a good lapping, those MLers showed great results.

I don't believe I would ever consider fire lapping. It seems as if it would do much more damage than help especially, to the throat.

JB can also cut your cleaning process down. Just use a few passes and then some solvent to remove copper.

Good Luck!

Reloader

I have tried it several ways, and came to the conclusion that all your doing is wearing out your barrel...Best way to lap a barrel in my opinion is shoot it...The other alternative is buy the best barrels..A Lothar Walther, for instance, is already lapped to a finer degree than anyone can lap it, to do so is going backwards.....

This sounds like a sensible way to firelap, and I think it reduces the damage to the throat that normal firelapping with jacleted bullets do.

Fire lapping very basically involves shooting a soft, BHN 11, oversize bullet impregnated with a high grade lapping compound through the bore of your firearm at airgun velocities. These abrasive bullets act like self conforming lapping plugs which incrementally remove constrictions in the barrel, uniform it dimensionally and smooth out the tooling and chatter marks in the rifling. Complete fire lapping step by step instructions may be found in the fire lapping chapter in the Beartooth Bullets Technical Guide.
In virtually all firearms it will either greatly reduce or totally eliminate both barrel leading and jacket fouling by smoothing out the tooling marks left in the barrel by the equipment used in barrel manufacture and by easing the sharp corners and edges inside the bore which collect fouling.
In most guns, there will be at least a modest increase in accuracy potential, to often times dramatic improvement in accuracy from increasing the uniformity of the bore dimensionally, and eliminating the constrictions which are common under dovetails in barrels, and barrel bands.
Especially in revolvers where the threaded barrel shank is screwed into the frame of the revolver, dramatic improvements in performance may be achieved. This is particularly true where cast bullets are used in the revolver, because the constriction under the threaded barrel shank (which can be from .002"-. 004" depending on make and caliber), acts like an undersize, bullet sizing die, thus sizing the bullet down under barrel groove dimension, creating an improper bullet to barrel fit. Not only does this condition deteriorate accuracy; it also promotes barrel leading. Fire lapping, properly done eliminates this conditionan.
Finally, fire lapping often times increases the nominal velocity achieved with a given load. This is accomplished by a reduction in the friction coefficient of the barrel. Lapping out even a small portion of the tooling marks in a barrel will reduce the friction coefficient of the barrel, at least to some extent.

A Note Of CautionYou will notice that the first paragraph about fire lapping specified the use of soft BHN 11 oversize bullets. There is a reason for this. The soft bullet will conform and swage down to the tightest part of the barrel, and not "spring back" to near original diameter due to its softness. Thereby the most aggressive cutting action in the barrel is at the point of constriction, and the remainder of the barrel basically gets no lapping action once that soft lapping bullet goes through the constriction. A harder bullet will "spring back" to some degree, and basically lap all parts of the bore at the same rate, thus enlarging everything uniformly, and not addressing the tight spots specifically.
I also mentioned oversize bullets. This is to insure equal lapping action not only on the tops of the lands, but in the bottoms of the grooves at the point of maximum barrel diameter as well. If the bullet is less than maximum groove diameter, it will only wipe off the tops of your lands, thus reducing the actual depth of your rifling. There is a popular practice out there in the shooting industry today to use jacketed bullets for lapping. Please use caution, and consider what I just presented, and the following concepts. Most barrels today are .0005-.0015" over what nominal accepted norms are for bore dimensions. Consequently, when lapping with jacketed bullets the only part of the barrel that gets lapping action is the tops of the lands and the bottoms of the grooves never get touched, which is where most fouling and leading occur, not to mention reducing the depth of your rifling by only wiping out the tops of the lands. Fire lapping isn't complicated, but it is tedious, and must be approached systematically with common sense.

I dont remember where I got this but I saved it for future reference.
Lyle

quote:

Originally posted by Atkinson:
I have tried it several ways, and came to the conclusion that all your doing is wearing out your barrel...Best way to lap a barrel in my opinion is shoot it...The other alternative is buy the best barrels..A Lothar Walther, for instance, is already lapped to a finer degree than anyone can lap it, to do so is going backwards.....

Ray

Something finally clicked and I connected the dots on that Lothar Walther comment. The newest gun and the one that I was considering lapping on is a Beretta Mato 300 win mag. After doing some research, I'm pretty sure that it has a Lothar Walther barrel, atlthough I haven't found out for sure. On their web site they don't mention what method they use for making their barrels (button rifled, cut rifled, or hammer forged) and don't mention lapping.

http://www.lothar-walther.com/us/index.html

I've only shot 128 shots out of it and don't see an evident problem. Still working on load development.

Think I've just been talked out of lapping.


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