Hand Lapping Barrels

[CaptnC]

I have been on a number of Web sites and i don't recall seeing thread about lapping your own barrel.

Why not?

Seems like it would be worth it...you see all the high end barrels list they are hand lapped...so it's doable.

Any one done it?

Any one willing to share some tips on how to do it?

Thanks
Cc

 

[MudRunner2005]

All of my customs that have been built with re-worked factory barrels, have had the bores hand-lapped. Break-in is virtually non-existent, cleaning is quick and easy, and accuracy is as good as any aftermarket barrel I've owned... If done right, there really isn't much downside to it, even with factory barrels.

 

[Dosh]

C, if you're up to doing it yourself try YouTube for a number of how to videos. It's not as easy as it looks however.

 

[CaptnC]

I know I read somewhere it takes about 1,000 strokes..which will take a while, but the benefits should out weigh the time.

I will ake a look at youtube and see what I can find...I'm not a big u-tuber

 

[bill123]

Is Tubb's Final Finish a good substitute?

 

[Capt RB]

If it's a factory barrel get it cryoed. If it still fouls badly you could try the tubbs final finish or the necco system. If it doesn't shoot after this any better have a good barrel put on or buy something else! Don't hand lap a barrel you are not going to rechamber.

 

[tim_w]

Hand lapping requires you to make a lead slug attached to a rod that is for the bore coated with lapping compound. Do it wrong and you can open up the muzzle ruin the crown etc. They are also done prior to chambering so that's another issue.

IMO if we are talking production grade barrels final finish using the top 2 or maybe 3 finest grit bullet groups. Polish the chamber with a very fine paste and a tight fit chamber mop.

Without a bore scope you are having to go totally by feel if you try real hand lapping. Too much and change the bore specs.

Lot of work for $100 barrel IMO but I guess if you are already casting bullets or have a melt pot for the lead etc but I would start on a barrel you do not care about to get a feel for it.

 

[J E Custom]

Lapping is not something that should be attempted by someone with little or no experience because of the many different scenario's the barrel presents and the requirements to do a expert job.

First, There is the evaluation of what's required by using a good bore scope. Next you would need to decide what size and how many Lapps
to make and what abrasive grits to use to lap the bore without destroying it. Then comes the actual technique of lapping to prevent oversizing the muzzle and throat. (Custom barrel that are lapped, are done so in the blank form so the ends can be removed far enough to get back to uniform diameters.) this is the reason that gunsmiths are required to take almost 1" off the muzzle of the new blank. The chamber end is not a problem because the chamber will remove that part of the enlarged bore.

If a barrel is already chambered and crowned the muzzle and the throat can suffer if not done correctly. If you have the tools to accurately measure the bore on both ends you can monitor the progress, if not you are guessing and have a good chance of ruining a good barrel.

By the way the bore is normally the tightest at the muzzle because the barrel maker measures the bore diameter before contouring and marks the muzzle end. Some even saw cut the muzzle to make the smith remove this oversized portion.

If you want to try it, By all means do but practice on a take off barrel
and measure the results.

PS: there is no magical number of strokes to a good lapping job, just the number it takes to reach a "Reasonable" condition/finish. with the grit and type used in the compound. I prefer 800 to 1500 and typically use two or three laps.

J E CUSTOM

 

[MudRunner2005]

Is Tubb's Final Finish a good substitute?

NO! Only if you have extensive barrel issues. Otherwise, it will eat the throat in your barrel and take out alot of bore material shortening your accurate barrel life.

 

[CaptnC]

Thanks to everyone for the help. Now I see why no one does their own barrels.

I watched a video last night that had me thinking it would not be worth the effort...now see everyone's input on the subject...I'm out...I have no idea how well the barrel will shoot or clean...so I'm going to do like everyone else and just shoot it! No need to take a cheap barrel and turn it into junk!

Thanks again for all the expert advice!

 

[BountyHunter]

The barrel makers have guys that are experts at lapping. This is not a rookie or even home project!

 

[CaptnC]

I'm certainly not going to try this but I am curious how much lead gets left behind during the process?

It would seem if the barrel is rough you would loose a lot of lead in the voids/tool marks...

 

[J E Custom]

I'm certainly not going to try this but I am curious how much lead gets left behind during the process?

It would seem if the barrel is rough you would loose a lot of lead in the voids/tool marks...

This is the reason I use several laps. As you lap a barrel, the lap wears
down and must be replaced. the hardness of the lap has to be just right to let the compound imbed, but not soft enough to get dinged up or deformed easily. I don't find a lot of leading to the barrel because the lead that wears off tends to be transferred to the compound and is removed every time you clean the lap and the barrel during the process.

I use a hard lead alloy (Like I use to cast bullets) for final finishing lap, using a non embedding compound for the best finish and the most accurate dimensional control. also, A mirror finish is not desirable because it can foul and reduce velocity. And a good honed finish is best (Just like in chambers).

Lapping can be laborious and time consuming if done correctly. So I only recommend it as a last resort on a completed barrel. Best thing to do to a new barrel is to do a shoot and clean brake in and let the bullet do the work. Cleaning often exposes the tool marks and aids the bullet in smoothing everything out.

J E CUSTOM

 

[CaptnC]

Thank you sir for the detailed reply.

I centainly don't have the skills it would need to "do it right"...not sure I would have the patience either!

Learned something today...

Thank you again for taking the time to educate us on the process!