steve_b_wales Posted January 9, 2015 Report Share Posted January 9, 2015 A question was asked by a mate of mine, to which I could'nt give a definitive answer. He is new to reloading and he said that with top quality cases (Lapua etc) the flash holes are drilled out, unlike cheaper makes where they are punched out. He asked me if I thought that drilling the flash hole just slightly bigger, would cause any problems. Personally, I would'nt, and told him so, but said that I would try and find out. What are your views? Quote Link to comment Share on other sites More sharing options...
Subaru_sti5 Posted January 9, 2015 Report Share Posted January 9, 2015 Personally I wouldn't try and alter a case only as I would assume that it has been manufactured that way for a reason, as to drilling or punching a hole out I can once again "assume" that a drilled out hole has more uniform edges and would allow for a more better dispersal of the "flash". I may be well off but that's my 10p Atb Quote Link to comment Share on other sites More sharing options...
seeker Posted January 9, 2015 Report Share Posted January 9, 2015 According to Lapua's manual they are punched ... If they're clear why add another variable? If you want to read about German Salazar test on small v large primer holes go have a rummage on 6mmbr. Gist is 'not a lot' .. Quote Link to comment Share on other sites More sharing options...
steve_b_wales Posted January 9, 2015 Author Report Share Posted January 9, 2015 Personally I wouldn't try and alter a case only as I would assume that it has been manufactured that way for a reason, as to drilling or punching a hole out I can once again "assume" that a drilled out hole has more uniform edges and would allow for a more better dispersal of the "flash". I may be well off but that's my 10p Atb Yes, that's what I read. A drilled hole is more uniform, enabling a better flash dispersal. He, or I are not going to attempt to try drilling them. It was just a question that I had no answer for. Quote Link to comment Share on other sites More sharing options...
Bewsher500 Posted January 9, 2015 Report Share Posted January 9, 2015 they are already there if you drill them you will make them bigger just get a flash hole uniforming tool if you are concerned but to be honest unless you already weigh your brass into cases batches, turn necks and anneal for uniform thickness and tension and are shooting groups in the 0.2" C2C category....... then uniforming flash holes probably isn't worth it! Oh and making them bigger is not a good idea as primers dont like the 50-60k psi through a big hole! Quote Link to comment Share on other sites More sharing options...
Kes Posted January 9, 2015 Report Share Posted January 9, 2015 (edited) There is a type of case which has 2 flash holes - cant remember the name now but french if I remember correctly. A comparison of single and double flash hole performance might give an insight ? Clearly the two flash holes are designed to do as you wish, increase the efficiency of the burn process. Edited January 9, 2015 by Kes Quote Link to comment Share on other sites More sharing options...
phaedra1106 Posted January 9, 2015 Report Share Posted January 9, 2015 Those cases are "Berdan" Primed (Military mainly) and mustn't be used with standard "Boxer" primers (as used in single hole cases). Best thing, if you're worried about your flash holes, is use a uniformer and also a flash hole de-burrer, it'll make very very little difference to things but at least they'll all be the same size and nice and clean Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted January 9, 2015 Report Share Posted January 9, 2015 There is a type of case which has 2 flash holes - cant remember the name now but french if I remember correctly. A comparison of single and double flash hole performance might give an insight ? Clearly the two flash holes are designed to do as you wish, increase the efficiency of the burn process. Two flash holes are normally berdan primer type cases very different from the single hole boxer primer type. Google it for more details. Do not change the hole size as you will change the back pressure which may cause the firing pin to pierce the primer. Quote Link to comment Share on other sites More sharing options...
Subaru_sti5 Posted January 9, 2015 Report Share Posted January 9, 2015 A lot of military rounds have 2 flash holes as to get the powder burning from more surface area rather than just straight up the middle with 1 flash hole, it's designed to give a better ignition and burn. Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted January 9, 2015 Report Share Posted January 9, 2015 The primer "anvil" for berdan is part of the case the boxer primer includes the anvil within it. If my memory is correct the berdan primer was invented in America but adopted in England the boxer primer was invented in England but adopted in America --- such is life. Quote Link to comment Share on other sites More sharing options...
Kes Posted January 9, 2015 Report Share Posted January 9, 2015 Those cases are "Berdan" Primed (Military mainly) and mustn't be used with standard "Boxer" primers (as used in single hole cases). Best thing, if you're worried about your flash holes, is use a uniformer and also a flash hole de-burrer, it'll make very very little difference to things but at least they'll all be the same size and nice and clean I was simply suggesting a comparison of the characteristics of ignition might give an insight into making a single flash hole wider. I was not advocating widening flash holes, or using double flash holes. Quote Link to comment Share on other sites More sharing options...
rem708 Posted January 9, 2015 Report Share Posted January 9, 2015 I would not increase the size of the hole. The reason - it allows powder to enter the primer chamber which adds to the burn when the primer detonates. If you tumble your brass you will also find the media sticks in larger hole Quote Link to comment Share on other sites More sharing options...
Dougy Posted January 9, 2015 Report Share Posted January 9, 2015 If you're mate is getting that picky then get a flash hole de-burrer, after that weigh and batch all the cases, weigh all the bullets for consistency and also measure them. You could stay in the reloading 24 7 but all your doing is chasing rainbows. (Insert BIG smiley) Im not quite 24 7 but I do keep thinking of ways to reach the pot of gold. But Ii enjoy doing it. Quote Link to comment Share on other sites More sharing options...
steve_b_wales Posted January 9, 2015 Author Report Share Posted January 9, 2015 If you're mate is getting that picky then get a flash hole de-burrer, after that weigh and batch all the cases, weigh all the bullets for consistency and also measure them. You could stay in the reloading 24 7 but all your doing is chasing rainbows. (Insert BIG smiley) Im not quite 24 7 but I do keep thinking of ways to reach the pot of gold. But Ii enjoy doing it. My mate is just starting up with reloading. He asks loads of questions, many, I can answer. But when he mentioned about drilling the flash holes, I did not know what to tell him except that I would'nt try it. Quote Link to comment Share on other sites More sharing options...
zx10mike Posted January 10, 2015 Report Share Posted January 10, 2015 really really dont drill the holes just de burr with a quality tool.my lapua drilled or not had loads of burrs so its worth doing. Quote Link to comment Share on other sites More sharing options...
Kes Posted January 10, 2015 Report Share Posted January 10, 2015 maybe a bit of research will answer the question - why one flash hole and why the diameter it is - there are amny other aspects though to reloading to master first - and, as mentioned previously, most, as I do, just use the flash hole reamer. Quote Link to comment Share on other sites More sharing options...
activeviii Posted January 12, 2015 Report Share Posted January 12, 2015 I drill out all primer hole and pockets. All done on lathe so its easy. I use a 1mm centre bit to drill the hole. You'll be surprised how many are smaller. us brass have slightly larger holes than some euro brass so uniforming your new brass and then every few firings will keep every thing the same. You'll be surprised the effect on accuracy from none uniformed holes. Bit, its like anything, how far do you take things. I'm a percentage loader. If I can bring my accuracy in on every stage of my loading by even 1% per stage then that brings it 8% closer than the guy next to me just on loading alone. Quote Link to comment Share on other sites More sharing options...
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