SmallCaliberCentral

Fellas, I have never worked on the flash holes on any of my cases for any of my rifles. The accuracy, especially in my 22 Hornet, 223, 204, and 270 Win, was always excellent. My 22-250, 222, and 243 were never real good, but good enough for what I used them for. I just neck sized the case, trimmed to length, chamfered the mouths, primed and loaded. What does deburring the flash holes mean, how do you do it, and what does it do for accuracy ? Please don't think I'm stupid, I never thought I needed to mess with it.

The flash hole is the little hole the primer pocket.When the primer is struck it shoots a flame through the "flash hole" to ignite the powder. The flash hole burr problems are from the manufacturing process when they drill,mold, or punch the flash holes. This process can leave a jagged burr in the inside of the case. I've seen burrs up to .075 long in some cases. These burrs can "funnel" the primer flame and not let it spread out as soon as it enters the case giving inconsistent powder ignition.The burrs kinda shield the powder kernels from getting 3rd degree burns . Basically what we do is cut a tiny chamfer on the flash hole inside of the case just like we do on the case mouth for bullet seating. K&M makes one of the best tools for this I'm told. For me, a MA Ford #1 5inch long carbide center drill gets the nod for this job. Once deburred, your good to go for the rest of the cases life.

RCBS makes a hand held tool that has an adjustment that will fit all different brass. It works well, just takes time of course and I always do all my new brass when I first get it......

I debur all my new brass with a RCBS hand held tool attached to my RCBS case prep machine. It only takes about 20 min. to do 100 pcs. Only needs done once & your good to go for the case life. Removing the bur sounds like solid advice to me , but I just have average shooting skills , so I have not noticed any improvement. I am sure benchrest shooters or others with more talent than I may see a difference. Deburing is such an easy step I figure it can't hurt to eliminate one more variable to improve my group size .