6BR Flash Hole Reamer
- Thread starter willyp19
- Start date
I use a kinneman's custom products one(dont think they are still in biz).
Its like the sinclair type that goes in the primer pocket sits flush with the bottom of the primer pocket and case head and reams out the flash hole so they are all the same,i believe in doing it.i seem to run into a case now and then that it cuts a bit but most of the time it barely touches them.but its just one of case prep steps i do to make sure im shooting the best cases i can make up and in my head if i have a shot out of my group and i did not do the flash hole,well its in my head and i blame that,consistant ignnition is everything in shooting small groups.but in alot of experimentation that i have done it does seem that the flash hole in the lapua cases should not be tampered with too much,this tool im talking about is the only one i would reccomend or use in the lapua case. now with that said i have experimented shooting the remington cases in my 6BR Norma chamber fire formed in there and have shot just as good of groups with them(.080 flash holes) i had 5 cases matched up and shot them every time i went to the range to see how long they would last i was up to 10 fireings on them and quit shooting them,i have a 100 of them put away for safe keeping.
http://www.sinclairintl.com/.aspx/pid=36020/Product/Sinclair_Flashhole_Reamer____0625
Its like the sinclair type that goes in the primer pocket sits flush with the bottom of the primer pocket and case head and reams out the flash hole so they are all the same,i believe in doing it.i seem to run into a case now and then that it cuts a bit but most of the time it barely touches them.but its just one of case prep steps i do to make sure im shooting the best cases i can make up and in my head if i have a shot out of my group and i did not do the flash hole,well its in my head and i blame that,consistant ignnition is everything in shooting small groups.but in alot of experimentation that i have done it does seem that the flash hole in the lapua cases should not be tampered with too much,this tool im talking about is the only one i would reccomend or use in the lapua case. now with that said i have experimented shooting the remington cases in my 6BR Norma chamber fire formed in there and have shot just as good of groups with them(.080 flash holes) i had 5 cases matched up and shot them every time i went to the range to see how long they would last i was up to 10 fireings on them and quit shooting them,i have a 100 of them put away for safe keeping.
http://www.sinclairintl.com/.aspx/pid=36020/Product/Sinclair_Flashhole_Reamer____0625
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Haydon's reamer tool uses the same 1/16" countersunk drill bits as K&M had... from the same supplier. And they suffer the same inconsistencies. The flash hole reamer I got from K&M was oversize and cut a 0.068 hole, and the one from Russ cut about a 0.066 hole. Some other units are "dead on". Luck of the draw.
My recommendation is to use a pin vice bit that runs under 0.060. I prefer to leave my flash holes small, at factory spec, i.e. 1.5mm which equals 0.059.
A high % of the tools you can buy will cut oversize. That's not an issue by itself, but it means, once you start cutting, you have to cut ALL your brass to match.
Other than removing obstructions (small flakes that blocks part of the hole) I recommend leaving your 6mmBR flash holes alone. It is difficult to uniform the holes with exact consistency when using most of the tools that work from the inside and employ a counter-sunk bit as the cutter. You end up with some flash holes that are chamfered on the inside and some that are not. That's why I'd agree with FJIM on the superiority of the tools that work from the outside (again provided the cutter is not oversize).
As always there will be guys who disagree with my recommendation, pointing out that world records have been set with .066 or .068 flash holes. I don't dispute those examples. However, I've never seen an improvement in accuracy by opening up the holes, and it's a lot of work that is unnecessary -- so long as the flash holes are not obstructed.
My recommendation is to use a pin vice bit that runs under 0.060. I prefer to leave my flash holes small, at factory spec, i.e. 1.5mm which equals 0.059.
A high % of the tools you can buy will cut oversize. That's not an issue by itself, but it means, once you start cutting, you have to cut ALL your brass to match.
Other than removing obstructions (small flakes that blocks part of the hole) I recommend leaving your 6mmBR flash holes alone. It is difficult to uniform the holes with exact consistency when using most of the tools that work from the inside and employ a counter-sunk bit as the cutter. You end up with some flash holes that are chamfered on the inside and some that are not. That's why I'd agree with FJIM on the superiority of the tools that work from the outside (again provided the cutter is not oversize).
As always there will be guys who disagree with my recommendation, pointing out that world records have been set with .066 or .068 flash holes. I don't dispute those examples. However, I've never seen an improvement in accuracy by opening up the holes, and it's a lot of work that is unnecessary -- so long as the flash holes are not obstructed.
When do i use this flash hole tool?,my theroy is this:After i have fire formed the case in my chamber and my primer pockets are cut all the same,now is when i use the flash hole reamer tool to insure there is no BRASS FLOW that may have tightend up or canted the flash hole,so after the case is fired(squared up)in the straight chamber and the primer pocket is cut then the flash hole tool go into the primer pocket of the squared case head and reams the flash hole all the same diameter and square to the pocket.i know im a finnatic. well thats my theroy and why i do it.I do believe it worth a few thousands on a short range target.I shoot mainly 100/200 yd groups.now for long range i dont believe that it could be seen on the target.but for sure the flash holes are VERY good to start with,but i believe doing it may way and useing the tool that goes in the back of the case is the correct way IF you decide to touch the flash holes on the lapua 6BR cases.The proof can be seen on the targets at short range.50% of my groups at 100yds are in the mid .100s.
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