Rich,

Looking at the grain structure of that magnum - is it usual for S & W to use a casting for the chamber ?

Tweakie.

Tweakie,
I don't know how it is manufactured and have never seen a cylinder blowout like the one posted. I have shot thousands of hot loaded rounds
over the years with mine. Fortunately it was not mine. Some 20 years ago there were a batch of 44's which had bad cylinders and owners were informered.
I had one of them, it was stolen, and wish the low life a gratifying experience.

My model will only use ammo manufactured by me, but then, it will won't be live.

RICH

Tweakie,

I am almost sure that is not a casting,  it probably looks like that because of the failure mode,  brittle fracture can look like that.
Sure glad I wasn't holding something like that it when it went off.

Arnie

You'r probably right Arnie, it's difficult to see from the picture.

Tweakie.

Back at it when time is available. I modified / improved the Atlas mill so it could reliably do 3D machining.
The engraving machine I used is limited in feedrate and 4-5 hour test runs is just not something that could be tolerated.
So attached are pics of a test done at 45 IPM. Took just 35 minutes to do, thus big decrease in milling time and quality is
good. An end mill was used  but a  ball mill will be used latter on for a better suface finish. Since there are places on the
barrel ie; top ramp and sides of the ramp that require a mattered or lined finish i wanted to see what the sharp end mill would
do.

Attached a few pic's of half the barrel showing machining steps and magnified view of both contoured and smooth
machining.
RICH

Any updates?   

Yes and no.......
Reworked the Atlas mill's axes and now have zero backlash along with a very accurate Z axis. So now I can mill to the desired tolerances at a higher rate of speed which really reduces the time for machining required profiles. There are some things that need to be made which are a real PITA and takes time.

In the mean time ........just punching holes in little targets with the attached instead of finishing the barrel started in the picture.
What can i say....get back into it this fall.

RICH
 

Any ideas on how to do this easily? Maybe it's more of a CAD question.

I need to machine checkering into the the concave portion of this piece. The concave is first machined and then i would like to follow up with milling in the checkering. The cutting tool may only scribe in the lines since the depth will be in the order of .006" or so.
So the gcode produced will just provide pathing that follows the concave surface / base lines of the triangles. Easy to do if i wanted to keep the pathing running perpendicular to the axis of the surface. But that would look dumb! The pathing needs to follow the suface on a 30-60 angle to the suface as shown in the pic.
Any thoughts or simple way to put the lines into  the surface of the solid surface so i could have CAM generate the code?
Guess you could slice the section into about 30 pieces and put 60 Gcodes together but that would be a PITA.
 
RICH

Post the cad file and I or someone will generate the CAM profile

The file is a .stl so you need to change the extension from dxf to stl.

You can assume that a point tool will be used thus the diameter is .001"  or it can be any diameter but the center of it follows the path.
Depth of cut into the convex surface is .006" with .008" spacing.

Thanks,
RICH