Flashhole diameter question

[Texas by God]

I just bought some 30-30 brass here with prepped/ enlarged flash holes so this thread is right on time! I will proceed with no worries now, dedicated mid range boolit loads for these.

[handloder]

The flash hole cutter blade on my Sinclair primer pocket uniformer tool measures exactly 0.080" using a Lufkin micrometer. Of course, all sizes of American primer flash holes are standardized at 0.080".

[cwlongshot]

This is Lake City Brass once fired and decapped.. I was suprized to see it.



CW

[Ed_Shot]

Often I recommend drilling out flash holes in rimless cases for use with very light loads to avoid case headspace set back. I recommend a 30 to # 28 drill for this with cases using LR primers. With small charges of fast burning powders under cast bullets this works well.

I have measured the psi and velocity of .308W cases with the flash holes so drilled with loads using 4895 and 311291 cast bullets up through 2200 fps alongside identical cases with identical loads without the flash holes drilled. No increase in pressure or velocity was measured however the ES and SDs were most often lower with the drilled flash holes.

Thanks for this info! I used a #28 bit on 50 ea. 308W cases experimenting with mouse fart loads and was wondering if it was safe to load them to @1600 fps.

[mold maker]

Many punched flash holes have a burr inside the case. Drilling removes it, and eliminates yet another variable which is very important with light or heavy loads.