Contouring a rifle barrel

When contouring a rifle barrel...

1) Should I use a water based cooling system, cutting oil or nothing?
(I don't like the water based cooling system because I don't want exposed ways to rust)

2) Is barrel heat an issue? When the barrel heats up under machining, does it not expand and lengthen? so, will this cause issues when turning between centers or even when mounted in the chuck and a live center at the tailstock? I was wondering about barrel bowing when turning my first barrel as it heated up.

3) Why do some barrel makers take so much time and effort to center the bore in the chuck as opposed to turning between centers using a lathe dog? It seems like turning between centers would be easier, faster and just as accurate...but hey, I'm a noob, otherwise I wouldn't be asking

4) Is there a good place or book to read on precision barrel making? I've seen some basic videos and piecemealed them with readings , but no one stop shop on how to do it.

I have no experience making barrels, but do keep in mind that most (all?)coolants contain rust inhibitors. Mixed properly, rust will not be your problem, on the part or machine.

Do you have a steady and follow rest?

Marc

Hi Jetpilot. I'm new at this too, but have been doing some work on barrels and may have answers to some of your questions.

1. I don't know what is "proper", but have been using cutting oil and taking smaller cuts on the barrels I have been working on. The barrel definitely sees more heat this way than if you were using a coolant for the cut, but like you I would rather go slow and not deal with the water-based coolant.

2. Let me answer #3 first...

3. Under perfect circumstances, the bore of a rifle is exactly aligned with the centerline of the bolt. The so-called "blueprinting" of a rifle largely consists of precision machine work to exactly align the bolt, receiver threads, receiver face, barrel tenon/threads and bore all on the same centerline. To achieve this when working with a barrel, it is critical to set it up in your lathe in a way that lets you cut true to the bore centerline. Now back to #2.

2. Because it is critical to perform barrel work on the bore centerline, working on centers seems like a good option, except for the fact a barrel is a long piece of steel. A barrel will flex under an unsupported heavy cut and will also grow in length as it heats up. Both of these factors make working on centers problematic. In order to get around this, most work I do (and have seen done) on barrels is done using a steady rest. This maintains center while also addressing the flex issue and the thermal expansion issue.



As for #4 - if you find it, please let me know... I need to order it as well!

Good luck,

Justin

there used to be a fellow that went by "speerchucker" in the gunsmith forum.
Straight forward common sense approaches to gun work, no BS. A lifetime in the business.

Unfortunately he got sick of dealing with all the crap. Search his posts.

All methods will work and produce accurate rifles. It is the gunsmith and the equipment that he has available, that determines how it will be done. For example, if you only have a South Bend 9A, you have to do your work between centers and with a steady rest. A South Bend Heavy 10 will allow you to also chamber thru the headstock. Both methods work, there is not one method that works better than the other if the gunsmith knows what they are doing. Go to the benchrest forums and you can see this argued out all the time.