Sinclair Lapua small rifle primer pocket reamer and Lapua brass

[dstoenner]

I stumbled across something that has bugged me for a few years. Sinclair makes 2 primer pocket reamers. One for normal SR pockets and 1 for Lapua. Because they say that the primer pockets on Lapua brass is deeper than normal primer pockets. So since I was just starting up on 6BR with Lapua brass about 5 years ago I bought the Lapua version. Well it never touched the bottom of the pocket. I thought, yep they are REALLY deep. So I went back to the Redding brush cleaner for primer pockets.

Fast forward to yesterday, I have some 6x47 Lapua brass I am prep'ing after a match and pulled out that primer pocket reamer to check if it would work on these pockets. I was working on my work bench in the afternoon and the bright sun was coming through the garage windows. It still isn't working but I see light between the case bottom and the reamer face. HUH??? So I check out the reamer and low and behold there is a radius from the reamer shaft to the face of the reamer. Looking at the Lapua case I see that the edge of the primer pocket is pretty sharp. So I get out my deburr tool and take some of the edge off the hole. Bingo, now the reamer is reaching the full deep. No light between the case and the reamer.

Great, now I have 465 6BR cases to fix and 340 6x47 cases to fix. 100 down.

So if any of you are as perplexed as I was about this primer pocket reamer not working, here is part of the answer.

HTH

David

 

[watercam]

I never felt the need to touch the primer pockets of my Lapua .308 SRP pockets. Perhaps they are not the same animal as other match cartridges. Primers were seated just under flush and have worked well for 25 firings. I did ream the flash hole to .0625" though. SDs in the 5-7 range.

 

[dstoenner]

I sort of agree but in doing this i did find that even in Lapua there is a variation in deepth. Most really cleaned up but some only was hitting the high spots. Not like more generic versions of brass which were horribly different.

It will be a while before i might actually be able to measure any improvement. It might be a mental thing knowing i have done all i can do

David

 

[Ned Ludd]

When I first switched to Lapua .308 Palma brass, I noticed the same thing right away. My .223 primer pocket tool would not reach down to the corners at the bottom of the pocket to remove the last bit of carbon gunk after cleaning. I purchased the K&M Small Rifle Primer Pocket Correction Tool with the sporty blue aluminum handle >>> problem solved.

 

[Martin52]

One for normal SR pockets and 1 for Lapua. Because they say that the primer pockets on Lapua brass is deeper than normal primer pockets. .....Well it never touched the bottom of the pocket.

Same issues here a few years back when I started using srp brass - this is the best tool I have found:

http://www.pmatool.com/pma-lapua-sm...niformer-complete-w-handle-and-power-adapter/

 

[Sixgun]

FWIW I use a k&m SP reamer for a 6547. You can adjust the depth and works great to chisel out spent residue after firing plus it keeps depth consistent.