Drill size for primer holes


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kestak
June 22, 2012, 10:25 AM
Greetings,

What size of Drill bit do you use to uniform the size of the primers holes?

Thank you

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Otto
June 22, 2012, 11:53 AM
Flash hole diameter is around .080" in the US, more or less. There is no real standard. IMO, drilling out flash holes is a waste of time.

LouieLouie
June 22, 2012, 02:27 PM
I think removing the flash around the primer hole inside the case and cutting the primer pocket to a standard depth is of more benefit than the hole diameter. I think I read that a larger primer hole puts too much back thrust/pressure on the primer cup - you don't want the primer to extrude (cratering) into the bolt.

rcmodel
June 22, 2012, 02:35 PM
I think I read that a larger primer hole puts too much back thrust/pressure on the primer cup Actually it doesn't.

Check out the flash holes in any of the "lead-free" handgun ammo now being sold.

You could drive a herd of mice through the 1/8"+ flash holes in them.

When reloaded they work just fine, and produce the same pressure & velocity as cases with standard flash holes.

rc

rondog
June 22, 2012, 02:52 PM
Just get a flash hole uniforming tool, Lyman makes them, probably everybody else too. It's basically a small center drill on a rod, with an adjustable stop for different calibers. Get one that will unscrew from the handle, and you can put the rod/drill part in a cordless drill. But it's made for de-burring the flash hole on the inside of the cases. Just cuts a tiny chamfer is all, but it will also drill the holes if they're smaller than normal. https://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1152&bih=515&q=flash+hole+uniformer&gbv=2&oq=flash+hole&aq=1S&aqi=g1g-S9&aql=&gs_l=img.1.1.0j0i24l9.2717.5055.0.7875.10.10.0.0.0.0.124.1076.1j9.10.0...0.0.bRaEYXdYN9s

243winxb
June 22, 2012, 08:51 PM
First, there are 2 different flash hole diameters.

rcmodel
June 22, 2012, 09:00 PM
Ahhh?

Did you intend to post an open link or two to your entire Photobucket account??

Nevermind.
I see some photos there I just gotta download. :D

rc

243winxb
June 22, 2012, 09:56 PM
RC, feel free to use. Oh, flash hole sizes. .0625" & .081" Now google drill size, but for what one? :confused: :D

Robert101
June 24, 2012, 02:04 AM
Drilling out flash holes...... That's a new one on me.

243winxb
June 24, 2012, 02:41 AM
One company did/does drill them at the factory. There are tools make for it, like this Lyman. Opens the hole to the correct size and puts a bevel on the inside. http://i338.photobucket.com/albums/n420/joe1944usa/Firearms%20%20and%20%20Reloading/FlashHole1A.jpg

T Bran
June 24, 2012, 03:27 AM
I bought some Fiocci .223 loaded with 40 grain V max bullets. These were very consistant at 100 yards which surprised me considering the cost as I was more intrested in the brass.
When I deprimed them and saw the flash hole I couldnt beleive that the decaping pin didnt break. They were off center so badly that I almost scrapped them. I loaded them up just for grins and kept them seperate. Once again they were laser accurate. Since then I just make sure there that there are flash holes visible in the brass if so its good enough for me.
If holes that far off center dont mess up the load and I mean 1/3,
or worse a slight variation in hole diameter doesnt bother me.
T

highlander 5
June 24, 2012, 08:49 AM
I've used a No 2 long center drill in the past.Used to have the drill size for uniforming the size of the flash holes but I can't remember it and the chart I had has gone the way of the dodo.

jmorris
June 24, 2012, 09:46 AM
When reloaded they work just fine, and produce the same pressure & velocity as cases with standard flash holes. Often with a lower SD.

First, there are 2 different flash hole diameters There are more than just two. In any case if you want to slightly enlarge and/or create a round hole a reamer is what you want to use.

Walkalong
June 24, 2012, 11:04 AM
Yes, more than two. Three standard ones here I know of, plus some oddball stuff out there.

The new "clean" primers were backing out of primer pockets from the force/velocity of the blast, so they enlarged the flash hole which dropped the pressure, fixing the problem.

243winxb
June 24, 2012, 12:47 PM
3, ok, i am behind the times. To answer the OP, found an old post of mine. Quote:
Most commercial cartridge manufacturers specify a 0.082" flash hole diameter. There are an increasing number of manufacturers using a 0.058" to 0.062" flash hole on some of the target cases such as the PPC, 6BR, and 223 Remington. If you are checking the .082" flash holes, use a #45 wire size drill bit as a gage.
http://www.sinclairintl.com/newsletters/99b1.html << Old link, but thats where info came from. New Link might help> http://www.benchrest.com/forums/arch...p?t-41950.html
Drill Size Chart > http://www.custompartnet.com/drill-size-chart Google knows all.

918v
June 24, 2012, 12:48 PM
Drilling out flash holes...... That's a new one on me.


That's because you are a novice.

jmorris
June 24, 2012, 04:07 PM
Or in a more Highroad way, you learn something new everyday.

Another area where drilling out flash holes is helpfull is if you are shooting wax, rubber or plastic bullets. With no powder charge its common for primers to back out due if the flash hole is too small (same goes for pellets shot out of centerfire brass w/o powder).

Walkalong
June 24, 2012, 08:21 PM
The only flash holes I have ever uniformed are 6 PPC for my Bench gun.

918v
June 24, 2012, 09:11 PM
I want to experiment with flash hole size to see how it affects accuracy in my Glock.

fguffey
June 28, 2012, 10:35 AM
Kestak, Before Internet Reloading there was Reloading, Back THEN there was a company that made flash hole gages, like RCBS says when offering Competition Dies and Gold Medal dies – Competition dies are not for everyone.

As you can see when you read through the responses, the diameter of the flash hole is not a concern of everyone. I suggest purchasing set of drill indexes of numbers and letters, good ones cost $100.00 +, for flash holes a set that starts at .100 maximum diameter would work for flash holes, you could use the shank end of the drill bit as a transfer to determine the diameter.

Those that drill all the flash holes suspect there is nothing to be gained, but it is a JIC thing – JUST IN CASE. Others? As in those that purchased the flash hole gages, and those that have shell holders for different purposes measured flash holes, again, if the reloader before Internet Reloading did not measure before firing and again after firing the money spent on the flash hole gage could have been spent on other tools.

I purchased 22,000 cases, mostly pistol, I started sorting when I came across a few I did not recognize, when looking for a difference I found the flash hole gage did not touch the wall of the flash hole and the cases had small pistol primers, for me it was too much trouble to sort by primer size, so, I offered them to a commercial reloader friend. He was not interested, the added time and cost and change time for him to reload 45 ACP ammo with large and small pistol primers meant he had to sort 45 ACP and load in two different stages. Does not seem like a problem but he purchased by the pound, the seller did not separate, this forced him to separate and then sell, by the pound, the small primed NT cases.


F. Guffey

fguffey
June 28, 2012, 10:42 AM
http://www.google.com/search?q=drill+index+chart&hl=en&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=7l7sT4WrNoes8ASNr4XZBQ&ved=0CGYQsAQ&biw=1536&bih=719

F. Guffey

kestak
June 28, 2012, 12:06 PM
Thank you all!

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