Flash hole deburring?

[Aitch]

Having a shop and wanting to make my own tools when possible, I started making a tool to uniform and chamfer the flash hole of my 6.5-284 brass.
I figured a section of .250" stainless rod and a #2 combined drill and countersink,center drill) would do the trick.
I was involved in setting the depth of the chamfer when I decided to check the fit of the drill in the flash hole.
The flash hole appears to be slightly smaller than the .078" diameter drill.
Will I be doing any harm by enlarging the flash hole to .078"?
How much of a chamfer should I put on the flash hole?
Of course, this operation is done inside the case.

Thank you,
Aitch

 

[trgtsnpr]

There is a flash hole deburring tool you can pick up for 15-20 bucks the large primer pocket holes are .080 and the small primer pocket holes are .062 so i guess your .078 drill will be ok just my 2 cents
heres a picture of the flash hole tool

 

[Aitch]

Thanks, I had not found any reference that told me what the flash hole diameter should be. I was checking aginst fired Norma brass not my new Lapua brass.