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Clean flash hole with drill bit
- Thread starter cw308
- Start date
Bucksnort1
New member
308,
It's not in the loaded case, is it?
It's not in the loaded case, is it?
Reloader270
New member
Lyman makes a universal flash hole deburring tool. It works very nice.
I use it to clean the flash hole, I do have the deburring tool that removes the burr from the inside of the case. the drill bit cleans the flash hole & opens up the flash holes that are on the tight side. I'm not enlarging the hole. I just can't remember the bit #. I am sure I originaly read the tip a the firingline, really worked great.
Flash holes have a range from as small as 0.069" to as large as 0.081" for regular primers and 0.125" for non-toxic primers and some high temperature specialty primers used in military and special pyrotechnics. The most common size, though, is 0.079", give or take.
This drill chart shows:
#47 = 0.0785"
2 mm = 0.0787"
2.05 mm = 0.0807"
#46 = 0.0810"
#45 = 0.0820"
So, based on that you would think #47 or 2 mm are the choices for removing material without opening the hole up. However, those numbers are maximum values and a lot of bits are a couple or three thousandths smaller to allow for wobble and flexing to open a hole a little. So you may well have had a #45 that fit OK. You could go to the shop supply store with a micrometer and see what sizes they actually have and go by that.
This drill chart shows:
#47 = 0.0785"
2 mm = 0.0787"
2.05 mm = 0.0807"
#46 = 0.0810"
#45 = 0.0820"
So, based on that you would think #47 or 2 mm are the choices for removing material without opening the hole up. However, those numbers are maximum values and a lot of bits are a couple or three thousandths smaller to allow for wobble and flexing to open a hole a little. So you may well have had a #45 that fit OK. You could go to the shop supply store with a micrometer and see what sizes they actually have and go by that.
Bucksnort1
New member
CW, do you use the bit in a drill or as a reamer held in your hand?
I had the bit in a hand held pin vice, cleaned the flash hole & kept them all the same size. I'm a benchrest shooter, I reload the same cases (20) get average of 25 reloads. Keep headspace to .001 (bolt action) so I can take the time & baby the brass. I Trim the case to 2.010 everytime 308 cal. uniform & clean the primer pockets. use the drill bit to clean the flash hole, clean the inside of the case neck with a bronze 30 cal. brush attached to a drill, Clean the shoulder & neck with 0000 steel wool. I enjoy preping the 20 cases, 50 may be a different story. Chris