Home Forums Reloading Big Game Rifles Rem 9 1/2M won't work in Norma Brass

Getting set up to load for a .375 H&H and prepped 20 brand new Norma cases. I primed 4 cases with a RCBS hand priming tool and noticed they were seating high. Stuck a case in the press and used the priming arm to see if they would go deeper. Nope..not happening.

Chambered a primed case in the rifle to confirm what I already knew, and sure enough there was a nice shiny mark from bolt face contact. Measured the primer pocket depth at .126 on the cases. The primers are .131 to .132.

I have some WLR large rifle and they measured at .126-.127. So now I've got 3000 of these Remington magnum primers and can't build any loads for my new. 375 until I get some more primers. A bit annoying! I wanted to shoot this rifle tomorrow, and not track down primers! I am not cutting the pockets deeper. Norma brass is to expensive for that. One box of the Rem primers I've had 6 or 7 years, and the rest I just picked up. They all measure the same..old and new. I use a lot of Rem 9 1/2 large rifle primers in Rem and Win brass for quite a few calibers without issues. This is a new one for me.

Boy, I guess that'll show them. If it's only .005" it wont take all that much work to correct the problem & continue on with your plans as long as you have a cutter, which it sounds like you might. I use a Hart (from Nescopeck... right across the river from Berwick) depth uniformer, chuck it in a slow drill, & can do 20 cases in less time than it took you to sign in & write the above. Any other quality tool will work as well. Or try the WLRs. They work very well for me in many rifles & are certainly hot enough for 375 H&H.

Dont ever try to load Sellier & Bellot brass. You really wont like that stuff.

I'm not sure I follow the reasoning here.

BTW I've found a bunch of brass needed cutting to accept Remington primers.

I've been using a carbide Sinclair for many years.

I was having a hard time coming to terms with having to fool with pricey brass. Honestly I've never ran into this problem until now. I have a primer pocket uniformer/cutter that fits my Hornady case prep center, so I'll try that.

Curiosity made me measure a bunch of primers just now, including Remington 9½M's, along with Federal, Winchester and CCI. Without exception all measure identically.

I've never had a problem with Remington though I only have one rifle that uses them. That one started off using metric RWS brass for a wildcat (338 Jamison). Expensive?!! No problems there nor with now using RUM Remington brass for that cartridge. I'd guess this problem was just one lot of brass that was just a tad off. Blame it on the brass, not the primers.

After some further experimenting I'm beginning to maybe suspect the shell holder. Its a brand new RCBS #4. Measuring from the bottom to where the case head sits when slid in measures .380. I measured 2 different #3 shell holders and they are .374 for the same measurement. My hand primer is the older style that uses the shell holders. This .006 difference would be enough to explain the high primer. I think what is happening is the tool is bottoming out before it can fully seat a primer. I did get some winchester primers and the issue is the same..

I need to get another shell holder and see if that makes a difference? I measured some primer pockets on some Rem 7mm-08 brass and they measure the same depth the Norma stuff and there are no issues seating primers. This is what is leading me to suspect the shell holder but I could be wrong.

Ran to the local gunstore and grabbed another RCBS #4 shell holder. I measured the old one again..and it is .381 from the bottom to where the case head sits. The new one is .376..so a .005 difference. Tried it and seated 20 WRLM primers..all slightly below flush..no high primers and no rubbing the bolt face. Last night when I tried to seat deeper on my Redding press I failed to notice that the priming arm was not protruding through the shell holder enough to fully seat either. This mystery has been solved.

How is the shell holder getting around the dimensions you gave earlier?

.126" pocket depth vs. .132" primer height

The anvil is being pushed flush to the cup when seating now. I took the measurement off the anvil. The lever handle on the priming tool was just bottoming out against the tool body. Now when the primer seats you can feel the handle wanting to push back at your hand slightly as it should when the primer bottoms out. I measured with calipers, I don't have a depth mic which would be more precise for measuring a pocket, but what I do know is everything is working now. I'm glad I didn't deepen the pockets. I did deepen 4 cases to no effect and that told me the problem was elsewhere.

Sounds like you did a good job of locating and solving the problem! Kudos! The engineer in me salutes you, sir.

Got it.

I have a couple of thousand 9 1/2's whose cup height won't allow their insertion into a pocket shallower than .130", and .132" is better for comfortably below flush.