Instead of applying lapping compound to a bullet then firing it; could one apply the lapping compound to the bore by saturating a cleaning patch and swabbing the bore, then just shoot light lead bullet loads?

Also, how exactly do you hand lap a bore?

Thanks

This link might help.

http://www.bellmtcs.com/FAQ/HandLapping.htm

This link might help.

http://www.bellmtcs.com/FAQ/HandLapping.htm


Actually, it doesn't help :-( Now I'm more confused- to lapp or not to lapp?

Well, I have been told not to do it.

The question regarding putting lapping compound on a patch and running it up and down the barrel: It does a great job of polishing a bore, but will do nothing for the constrictions and abnormalities found there, as the patch will obviously compress under the constrictions and merely uniformly polish the interior surfaces. The real culprits in the barrel interior are the constrictions that only lapping will releive.

Hand lapping, yes it does work, and has been used for years to get rid of the same constrictions addressed by fire-lapping. However, I've seen more barrels ruined by hobby gunsmiths hand-lapping their guns than any other single method. The fact of the matter is this, if the poured lap skagg gets the least bit loose in the barrel, which it will from the abrasion resulting between the barrel and the skagg, the lapping skagg can and will develop slop in the barrel which will ultimately round-off the corners of the lands, thus greatly diminishing their effectiveness, and adversely affect accuracy. The cure to this when hand-lapping is to frequently pour a new lap skagg, or to bump-up the diameter of the skagg while it's in the barrel with a closely fitting rod and a hammer. While it does work, and many professionals who do such work for a living are expert in the practice, the vast majority of hobbyists would be much better served by firelapping.

Here's why. In firelapping a bore each and every abrasive imbedded bullet fired down the bore acts as a precisely fitted lapping skagg, making only one trip down the barrel, and of course fitting the contours of the bore precisely. Also there is no danger of ringing a barrel by overly "bumping-up" a hand-lapping skagg in the bore. Too, there is not the abrasion hazard either from the breach or muzzle end from a rod that is contaminated with lapping compound either ruining a crown, or chamber. Finally, fire-lapping is SO EASY! It provides a much safer and easily applied method to releiving the constrictions in a barrel when compared to hand-lapping. Lastly, firelapping can do something that hand lapping cannot: it can produce a barrel with a slightly tapered bore, being somewhat larger in the breach and tighter at the muzzle, thus creating an ever increasing grip on the bullet as it traverses the bore, and virtually eliminating any gas blow-by around the bullet in the barrel.

When PROPERLY firelapped (read soft oversize LEAD bullets at AIR GUN VELOCITIES), I have never seen or heard of a gun that had experienced deteriorated accuracy, but always a remarkable reduction or outright elimination of fouling, a modest increase in velocity due to a reduced friction coefficient in the barrel, and most usually at least a modest and sometimes dramatic increase in accuracy.

Many of our customers have reported that guns which were on their "trade-off soon" list due to poor accuracy have become their favorite shooters after firelapping due to the night and day difference in accuracy after firelapping. Too, firelapping will nearly always either greatly reduce or eliminate leading when firing alloy bullets.

All I can say is that naysayers on firelapping either haven't tried it, or haven't PROPERLY done it!

Hope this helps!

God bless,

I'm with Marshall - call up the boys at Shilen (or any bench rest barrel manufacturer), and ask them how much skill is involved in hand-lapping a barrel.

I will say, I fully intend to hand-lap a barrel one these days, but I'll go into the project with full knowledge that I may screw up, and need a new barrel.

That's the risk/reward with handlapping; if you aren't willing to screw it up, stick with firelapping.

There is a very detailed description of handlapping a barrel in one of the Handloaders' Digests (forget which year) written by Ed Harris (who occasionally stops by the forum). I'd suggest reading it before you go down that path.

Like Marshall says, firelapping is just so simple it's hard to think about trying anything else.

Good luck!

Thanks for the replies guys,

...But what about applying the lapping compound to the bore with a patch or something, then "fire lapp it" by firing ordinary lead bullets at low velocities?

I'm thinking that; this would cause a reverse taper since the lapping compound would build up in front of the "ordinary" bullet and cause more lapping towards the muzzle end than the breech end - instead of wearing off as a bullet with lapping compound applied directly to the bullet would- is this correct?

...If so, then I'll just follow the instructions in the kit I ordered from Marshall.

If anyone is wondering; I'll be lapping a Ruger Blackhawk that isn't particularly accurate with cast slugs and likes to lead.


Thanks again,

I think it would be a lot less trouble to load the compound on a bullet, to be honest.

I agree with MikeG. When I firelapped the barrel on my .41 Blackhawk the instructions for lapping said to roll the unloaded bullet between two peices of glass. load the bullet as a squib load and shoot.

However, the rimfire instructions said to dip the lead bullet into the compound and then fire the gun that way. I wondered why this wouldn't work for center fires and when I tried it on a Contender barrel, it worked. It did seem to use more compound and was dirtier to work with.

regards,
Gene

I used the NECO system and it will move the throat out on a rifle. I rolled the bullets between two steel blocks coated with abrasive to impregnate the bullet.

I used the NECO system and it will move the throat out on a rifle. I rolled the bullets between two steel blocks coated with abrasive to impregnate the bullet.

Jim,

Indeed! Your experience with the NECO system pretty much mirrors that of myself, and those with whom I've communicated that used their product and protocols. Jacketed bullets and abrasives are pretty tough on the throat of a firearm, especially when pushed to near normal velocity thresholds for the cartridge of interest.

This is exactly why in my earlier post I specified SOFT OVERSIZE LEAD BULLETS and AIRGUN VELOCITIES! If following this approach, changes in throat configurations won't be an issue.

We have spent a huge amount of time and resources (and I might add ruined barrels) in arriving at the system of firelapping which we advocate! And when done correctly as I've said before, I've never seen a barrel PROPERLY firelapped to the detriment of accuracy.

Thanks for the comment!

God bless,

I would not reccomend using a patch to place the lapping compound in the bore and then shoot a lead bullet over it. I can see really bad things happening.

You risk blowing up the barrel because the compound will build up in front of the bullet somewhat like snow does in front of a snowplow. Eventually the bullet may reach the point where the resistance is too great and it could ring the bore or blow up the barrel.

I also think that it would be too hard to control the amount of lapping coupound that you place in the bore vs. the amount that you place on the bullet. A bullet will only hold so much compound, and then it "is full", but it would be so difficult to apply the same amount to a barrel each string of shots, and it would be so difficult to insure that it was evenly distributed.

Lastly, I do not think that it would be very practical to coat the bore vs. a bullet because it would require so much more compound to get the job done. You'd shoot most of the compound out of the bore every shot and then have to recoat the bore vs. the amount that you place on a bullet per shot.

I do not have anywhere near the expertise that some of these other folks do, but those are some of the reasons that I have never used that method on any of my guns. Good Luck with whatever you choose.

Marshall,
If I do anymore fire lapping I was going to do just that. I figured the lead bullets would be less harsh on the throat and hold the abrasive better on down the tube. I fired them at pistol velocites 1000 to 1200 fps. And will lower this velocity some. But air guns are now at 1000 fps ;)

Yikes! I do stand corrected regarding air-gun velocities.... I was referring to my childhood recollections of an old Red Rider! The target velocity threshold for optimum lapping action is between 400-600 fps.

Yikes! I do stand corrected regarding air-gun velocities.... I was referring to my childhood recollections of an old Red Rider! The target velocity threshold for optimum lapping action is between 400-600 fps.
I thought you were!! ;)