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What SAFE size to drill out lapua small primer brass

DLT

Silver $$ Contributor
I have another thread going, Having an issue with a rifle and have decided to try new lapua brass I have been holding onto. It’s for a 6 creedmoor I do not want any hangfires or stuck decapping pins. What size do I need to ream the flash holes ? I believe you guys have it down to a science now lol. Thanks
 
DLT said:
I have another thread going, Having an issue with a rifle and have decided to try new lapua brass I have been holding onto. It’s for a 6 creedmoor I do not want any hangfires or stuck decapping pins. What size do I need to ream the flash holes ? I believe you guys have it down to a science now lol. Thanks
Click to expand...
Just as you are seeing in the replies, Don’t Do It..!
I drilled out flash holes for a friend’s PPC brass and his accuracy went into the toilet..!!
Ended up putting them in the brass bucket at the range as he was too honest to try to pass them on to anyone else…
Get a de-priming pin to suit the job and leave the brass as the manufacturer made it.
 
Fire Dog said:
Just as you are seeing in the replies, Don’t Do It..!
I drilled out flash holes for a friend’s PPC brass and his accuracy went into the toilet..!!
Ended up putting them in the brass bucket at the range as he was too honest to try to pass them on to anyone else…
Get a de-priming pin to suit the job and leave the brass as the manufacturer made it.
Click to expand...
Ok. I have read enough on here to leave them alone.
 
For my 6.5 Creedmoor I thought the primer hole was to small and just punched it out with a regular RCBS large primer sizing die and de-burred the inside edge of the hole. Then just use 450 primers and they are more accurate with more velocity. I have never had a pin get stuck or break. But that is with IMR 4350 or RL16 powder.
 
Lee sells undersized decapping pins specifically for the small flash hole for their decapping die.

I have a spare one sitting if you need it as I no longer have that die.

leeprecision.com

USIZE UNIVERSAL DECAP

Undersized flash hole universal decapping pin.
leeprecision.com leeprecision.com

eta - link
 
Most decapping pins are Ø1/16" (Ø0.625") and the Lapua 6mmBR flash hole is Ø0.059". This flash hole diameter is critical and must not be changed. If you cannot find a small diameter decapping pin (as was the case for me several years ago) take the standard decapping pin, chuck it in a lathe (or a drill will do) and use a file to decrease the diameter to Ø0.058-0.057. By the way, the reduced diameter decapping pin still works fine for the large primer flash holes - I never change the pin whether I am decapping large or small primers.

Good luck.

Alex
 
As many of you may have figured out by now, I do love to experiment. :D

Not long ago I got some Alpha .308 SRP brass and found I got some excellent results right of the bat. It was interesting to me when I found out that Alpha Munitions produce their SRP .308 brass with a flash hole diameter of .080" (compared to what I'd typically expect of .059" for SPR brass). They posted a report as to their testing and why they went with the larger flash hole, citing better or more consistent performance. So . . . I had to see what would happen if I enlarged the flash hole for some of my Lapua SRP .308. Well, they performed pretty well, but I can't say, yet, that I could distinguish their performance from those with the smaller flash holes. For me, performance just didn't "go into the toilet". :rolleyes:
 
jds holler said:
I read a thread like this one, and I get to thinking -- how many of us ever check our batch of brass for consistent flash hole size?
-- and how often do we get a troubling flier for no apparent reason. :oops:
jd
Click to expand...
If you're not checking, you should be.

Thread 'Lapua 6BR flash holes'

Lately, I've noticed quite a bit of variation of flash hole diameters on later Lapua 6BR cases. In the past, I've just opened them all to .0625 for a consistent size. But on some new 30BR cases I'm finishing, the diameters were all over the place.....from a few at .057 all the way to .062 as verified by a pin gauge. With a 20X loupe, all the holes were nice and round with no slivers of material to skew the measurements. This was from 50 cases this morning...you can see by the material that some holes were just touched up and some had quite a bit more removed.

Good shootin' :) -Al...
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