Custom rifling of MY bar stock?

F

FrankenMauser

New member
Today I picked up a really unique piece of steel bar stock.

What I'd like to do with it, is turn it into a rimfire barrel.

Does anyone have any recommendations for shops that might be willing to deep drill and rifle MY bar stock?

I know there are plenty of places that will do custom rifling, so long as they're in control of the materials. But very few places are willing to risk damage to their tools by using unknown materials, or even just 'foreign' materials.


Anybody have any suggestions?
 
Just wanted to add:
I know another option is to bore the bar and use a liner, and I'll still keep that in mind. But I'd really like to get this rifled, if possible.


I'd like to keep this as a bit of a secret project, so I'm not going to divulge exactly what I've got here. But I will state that the material has a minimum 70k psi yield strength and about 95k psi tensile strength, and is a minimum of 1" thick in each direction (and about 40" long).
If I'm reading my 'materials properties' correctly, it's roughly equivalent to 416 stainless.
 
Some stainless steels are pretty grabby if they are not designed to be free machining steel, especially when dead soft, as your tensile strength and yield numbers suggest yours is, and can create a lot of friction with a cutting tool. Also, if the stock is not adequate quality it could have inclusions that could chip a cutting edge, so it's understandable that shops will be reluctant to risk the well-being of the drill, reamer, and rifling cutter. For button rifling, the possibility of creating high stress in an unknown steel is another concern. Not to mention, some steels sound great on paper, then don't work safely in guns. I remember reading that some folks tried experimenting with grain oriented steel in barrels at one point, thinking that if it's good for a samurai's sword it must be good for a gun barrel, only to find the result very weak perpendicular to the lengthwise orientation of the grains and prone to bursting upon firing. So the makers may think there is a liability issue, too, even at .22 rimfire pressures. You could ask if you supplied the cutting tools if they would then be willing to try, but they won't be economical to buy unless you want to have a number of barrels made.

Some years ago Guy Lautard had a couple of video tapes (yes, that long ago) available of a boring and rifling machine that was home brew. It's still available on his web site, if you want a very involved hobby. The original had a wood frame, but was upgraded later to steel, as this photo shows.
 
Steels like 4150 can be semi-tough to machine, too, unless you order it resulfurized, or leaded. When you get into stainless, it can even work harden, then you are up the creek. (I was sawing off the end of a 3/4" stainless pump shaft, in a bandsaw, and it work hardened halfway through, ruining the blade. It required an abrasive cutoff wheel, and a good bit of time, to finish the cut.)

You would have to contact the barrel manufacturers, and ask if they can machine what you have, and give them the material type. It could be that the material might not be able to be gun drilled.
 
Thanks guys.


Scorch, I'm not sure if JES is set up to drill a virgin blank. But, I hadn't even considered him for this job. I'll give him a call and see what he says. (Probably something involving the words 'crazy', 'expensive', and possibly even 'stupid'.)
 
Probably something involving the word liability. The 'expensive' will just be. snicker.
Re-boring and re-rifling isn't the same as drilling an absolutely straight and precise 40" hole through an unknown material.
 
Re-boring and re-rifling isn't the same as drilling an absolutely straight and precise 40" hole through an unknown material.
Click to expand...
Indeed.

But it's not going to be a 40" hole. That's just the overall length of the piece of stock that I've got.
I wouldn't keep the machinist in the dark, either. They would be well aware of what the material is.
 
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