Home Forums Hunting & Shooting Ask The Gunwriters Barrel Slugging?

Hi Ken, I was wondering how one goes about "slugging" a rifle barrel? I have searched hi and lo and found little information worth processing.

Are there "kits" available like the firelapping kits from Neco.

Thanks

True Eyes

Slug lapping is a process where a lead slug is pulled though the bore. Most premium barrel manufacturers use some form of lapping to finish the bore after cutting the rifling. Slug lapping is best left to a competent gunsmith. If done incorrectly you can cause unbalanced wear in the bore and create even more problems for yourself. There are several smiths who specialize in this process. I would go this direction "IF" lapping was necessary

To lead lap, a steel rod is placed in the bore and molten lead slug is formed around the end of the rod. Once the lead is solid, lapping compound is applied to the slug. The slug is then pulled back and forth until the desired finish is achieved. You can also do the same thing with fiber disks which are designed to hold the lapping compound and conform to the bore.

Fire lapping is decidedly more destructive to the bore. Both the Tubb and NECO kits use caliber correct lead bullets impregnated with an abrasive. The problem with fire lapping is - it�s substantially more abrasive than slug lapping. Because of the velocity of the bullets and the pressures involved with internal ballistics, fire lapping will erode the chamber throat. This causes premature wear of the bore. Sure you will lap the barrel, but you will also cut a lot of life from the bore. Most folks consider this process a last resort before tossing the barrel in a lake.

When anyone starts talking about lapping, the question �Why?� always springs to mind. Slug lapping is designed to polish the bore to control fouling. It does not make for a more accurate barrel. However, controlling fouling can make for more accurate shots between cleaning.

Generally, even the most rough factory tubes can be ironed out by break-in and proper cleaning. A few patches of JB bore paste during routine cleaning will help safely expedite the process. I use a bore scope to monitor bore condition in my rifles. You can actually see a considerable difference between a new factory bore and one that has been shot 100 times. IF after a 100 rounds, you are still having a lot of fouling (and you know how to properly clean between strings) then lapping may be the cure.

However, every time I have inspected a �real fouler�, I find that the bore has not been cleaned properly and fouling has been allowed to accumulate. Make sure you are cleaning properly and removing copper from your barrel before you decide to lap. I have never found a factory bore that needed to be lapped. Proper cleaning and break-in will solve 99% of the problem.

Why do you feel you need to lap?

ZeroDrift,

I recently inherited an older M700 in 3006. After a thorough cleaning using Sweets and Shooters Choice I shot the rifle and it still did group consistently. I inspected the bore and crown using my Hawkeye and noticed some "rough" spots on the rifling.

I have never attempted to "lap" a barrel. So I justed to get some info to see if it was worth while to make the attempt or just have a new barrel screwed in.

But thanks for the info, I appreciate it.

Best

True Eyes

v - The rough spots most likely are not causing the problems. I have seen quite a few very rough and pitted bores shoot MOA or better. They may foul like a dickens but they still can shoot. As long as the bullet jacket is not being overly abraded, it will go to sleep with no problems. There are a dozen accuracy gremlins that could be causing your problems, fire lapping or lapping would be way down on the list of possible solutions.

Even though the crown looks OK, I would have the gun re-bedded and re-crowned. That is after checking all screws and testing your scope to ensure this is not causing the problem. You may want to pull the action and inspect for barrel contact or a hidden stock crack. Whenever I find a gun that just wont shoot, pulling everything apart and putting back together is a good start.

A couple of questions....

Do you know if the rifle ever shot well?
If so, when did it fall off?
Are you using hand-loads or factory loads?
How much load development have you done?
How many rounds through the bore do you estimate it has seen?
What does the throat look like thorough your bore scope?

Slugging a barrel is also reference to shoving a soft, pure lead slug down a barrel in order to get accurate measurements of the lands and grooves. I would think it would take a dead soft lead slug of about the right dimensions.