300 mag primer seating

[IdahoJoe]

I have a RCBS hand priming tool (not the universal). I have been reloading for a friends 300 WM and when I set the primers using the hand tool they primers are all not seated completely. I have used this tool before on my 338 WM with the same shell holder. Along with several other calibers using different shell holders and never had a problem. I contacted RCBS and they sent me new internals for the priming tool. I changed them out and have the same problem. The brass is Norma, Winchester, and Federal. Problem on all three. I have been re-seating the primers in my press but it is annoying. Should I try the #26 Shell holder.

Thanks for Advice in advance

 

[FEENIX]

Should I try the #26 Shell holder.

I would ........................................................... or get the universal type!

 

[Dosh]

Joe, did you use a primer pocket uniformity tool? A Sinclair or others are made to make primer pocket depth equal in depth and to spec. Perhaps it would help, unless you have performed this already. Good luck

 

[IdahoJoe]

I haven't tried a primer pocket uniformer. They seam to be uniform just not seated. Might be a good next step. How well does the universal one work. I thought about getting that one but decided it would probably not work as well as the one with the shell holder

 

[FEENIX]

I haven't tried a primer pocket uniformer. They seam to be uniform just not seated. Might be a good next step. How well does the universal one work. I thought about getting that one but decided it would probably not work as well as the one with the shell holder

Very well!

 

[IdahoJoe]

Well Hindsight is 20/20 I guess.

 

[Lefty7mmstw]

I have seen a lot of shallow ww brass lately; I've had to ream the pockets on most of the ww brass I've bought in the last few years or the high primer crap is present. That doesn't explain the other brands but it may help to ream and uniform the pockets to eliminate that issue.

 

[AZShooter]

I also couldn't get the primers to seat deep enough in Norma brass even with my RCBS press! Don't know why but the norma brass has been shallow and tight in several different cartridge sizes I have tried over the past two years.

I HAD to use the RCBS primer pocket uniforming tool to remove some of the brass from the bottom of the pocket.

link for tool: RCBS Trim Mate Case Prep Center Carbide Primer Pocket Uniformer

I found that tool at Sportsmans. I chuck it up in my rechargeable drill and place the drill in a vice. The darn pockets on those Norma cases are so tight I have to add a drop of water to the uniformer to help lubricate things. Also I make two passes cleaning off the brass from first pass.

After all this work you may not have enough pressure with your handheld unit to seat the primers. I only use the RCBS press for seating primers in Norma brass.

 

[Dosh]

Joe, please avoid the adjustable primer pocket uniformers, they are difficult to secure and the adjustment can slips on the shaft. This cuts a pocket too deep which is dangerous. The newer RCBS and the Sinclair uniformers are preset to SAAMI spec and are carbide for long life.

 

[Lefty7mmstw]

I've got the lyman hand tool.... The carbide bit has a fixed shoulder and it comes out of the driver handle so you can chuck it in a drill and give them heck if you have a bunch of brass to do... it also works well as a carbon remover when cleaning/ sizing brass... I don't even know where my actual primer pocket scraper is...