Raifuru Posted May 9, 2014 Report Share Posted May 9, 2014 I was reading a section on 6BR where it suggested reaming the Lapua 6.5 x 47 brass for a 0.0625 flash hole. When I measured the hole (albeit with a drill bit) they all seem to be 0.0625 already. Was this an issue with older batches of the brass? Link to comment Share on other sites More sharing options...
Andrew Posted May 10, 2014 Report Share Posted May 10, 2014 Perhaps they meant "uniforming" the holes to .0625"? ~Andrew Link to comment Share on other sites More sharing options...
Laurie Posted May 10, 2014 Report Share Posted May 10, 2014 Lapua small-dia flash-holes (220 Russ / BR / 6.5X47L / 308 'Palma' case) are nominally 1.5mm = 0.0590", but like anything made en masse may vary a little. So the game plan is to use a special small-dia. flash-hole reamer or uniformer that opens them up by 0.0035" to 0.0625. See the Sinclair model second from left in the top row that indexes off the primer pocket as an example. http://www.sinclairintl.com/reloading-equipment/case-preparation/flash-hole-deburring-tools/index.htm Standard flash-holes are 2mm = 0.0787" and equivalent tools for them open them up to around 0.081". The effect of such small increases have a marginal effect on pressures and MVs, but by 'uniforming' them hopefully improves charge ignition and burn consistency marginally. The Sinclair type shown doesn't debur the inside or exit end of the flash-hole which in the case of much US made brass that has punched through holes (unlike RWS, Norma, Lapua which are drilled) usually makes a larger improvement than uniforming the hole itself. Many bench shooters don't consider it worthwhile touching 220 Russian (basis of the PPC) or BR Lapua case primer pockets or flash-holes. It is STRONGLY advised not to use a standard 0.081" uniformer on any small flash-hole model. If they're opened up much beyond 0.070", groups and velocity spreads almost invariably increase too. Link to comment Share on other sites More sharing options...
dylan5588 Posted May 10, 2014 Report Share Posted May 10, 2014 Lapua small-dia flash-holes (220 Russ / BR / 6.5X47L / 308 'Palma' case) are nominally 1.5mm = 0.0590", but like anything made en masse may vary a little. So the game plan is to use a special small-dia. flash-hole reamer or uniformer that opens them up by 0.0035" to 0.0625. See the Sinclair model second from left in the top row that indexes off the primer pocket as an example. http://www.sinclairintl.com/reloading-equipment/case-preparation/flash-hole-deburring-tools/index.htm Standard flash-holes are 2mm = 0.0787" and equivalent tools for them open them up to around 0.081". The effect of such small increases have a marginal effect on pressures and MVs, but by 'uniforming' them hopefully improves charge ignition and burn consistency marginally. The Sinclair type shown doesn't debur the inside or exit end of the flash-hole which in the case of much US made brass that has punched through holes (unlike RWS, Norma, Lapua which are drilled) usually makes a larger improvement than uniforming the hole itself. Many bench shooters don't consider it worthwhile touching 220 Russian (basis of the PPC) or BR Lapua case primer pockets or flash-holes. It is STRONGLY advised not to use a standard 0.081" uniformer on any small flash-hole model. If they're opened up much beyond 0.070", groups and velocity spreads almost invariably increase too. A bit off topic but I had a problem with Hornady Hornet brass the small decapping pin supplied with the RCBS dies jammed in the hole, Are the flash holes in Hornady brass smaller in general? It is ok with every other brand of brass I have used. Regards Aj Link to comment Share on other sites More sharing options...
Laurie Posted May 10, 2014 Report Share Posted May 10, 2014 They shouldn't be any smaller. What I've found with some batches of Hornady brass is that the odd example sees its flash-hole not properly punched leaving a really big lump of brass hanging inside the case. It may be that in your case such a shard was partly blocking the hole and caused the decapping pin to stick. Link to comment Share on other sites More sharing options...
dylan5588 Posted May 10, 2014 Report Share Posted May 10, 2014 They shouldn't be any smaller. What I've found with some batches of Hornady brass is that the odd example sees its flash-hole not properly punched leaving a really big lump of brass hanging inside the case. It may be that in your case such a shard was partly blocking the hole and caused the decapping pin to stick. It wasn't just the odd one It happened with every one, in the end I had to make a pin from an old drill bit to de cap, The holes were noticeably smaller. I then drilled them out to match the holes in the other brands, Winchester, Remington, etc Aj Link to comment Share on other sites More sharing options...
Laurie Posted May 10, 2014 Report Share Posted May 10, 2014 Had to be a manufacturing fault then - wrong diameter or damaged punch. Link to comment Share on other sites More sharing options...
Raifuru Posted May 12, 2014 Author Report Share Posted May 12, 2014 Ah. I have been using a 1.5mm drill bit on the assumption that was 0.0625, but as it is obviously udersize, no reaming was done. Sinclair seem to be the only people who sell them. Link to comment Share on other sites More sharing options...
Laurie Posted May 12, 2014 Report Share Posted May 12, 2014 K&M does one that works from the case-mouth end and which is cheaper than the Sinclair type, if you can find a UK supplier. (Spud?) http://www.kmshooting.com/catalog/flash-hole-uniformer-tools/flash-hole-uniformer_professional-ppc_0062.html Link to comment Share on other sites More sharing options...
Raifuru Posted May 13, 2014 Author Report Share Posted May 13, 2014 K&M does one that works from the case-mouth end and which is cheaper than the Sinclair type, if you can find a UK supplier. (Spud?) http://www.kmshooting.com/catalog/flash-hole-uniformer-tools/flash-hole-uniformer_professional-ppc_0062.html Thanks Laurie Link to comment Share on other sites More sharing options...
1967spud Posted May 13, 2014 Report Share Posted May 13, 2014 Thanks Laurie yea thery are in stock , well the complete range from KM Precision iis in stock even the new left haanded neck turners Link to comment Share on other sites More sharing options...
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