Baffled ???

[Varmint Hunter]

I've been struggling with a persistent problem which I just can't seem to figure out or eliminate.

Working with Rem brass in 338 RUM:

all brass is fully prepped including a careful uniforming of the primer pocket using a Sinclair carbide pocket uniformer, which is non-adjustable

priming with Federal 215M's which measure .127-.128 from top to bottom

i measured the cutting portion of the tool and get .130"

pockets seem to measure .130" deep after uniforming with the tool, as measured with the tail end of my digital calipers

THE PROBLEM - I seat the primers using the priming arm of my Rockchucker press. I have considerable leverage while using the press and can feel the primers bottom out. However, when I place the loaded cartridge in the calipers I can clearly see light all around the protruding primers. Place a cartridge on a piece of glass and it wobbles slightly.

I have tried to use more force than is appropriate to further seat the primers. This will cause a slight flattening of the primer head but does not eliminate the problem.

Exactly what am I missing here?

 

[Joe King]

Dial/ digital calipers aren't perfect and can be hard to use in that manner as you've just seen. Their better suited to inspection duties. A depth micrometer is what you should be using. I'm not saying run out and buy one, just whats the correct tool for the job, you can get by with your calipers just fine but realize their far from ideal or perfect, and getting by is what you'll be doing.

 

[Mike 338]

I've had problems with protruding primers. I cant remember which primer I was having the problem with but changed to CCI and have no problems since.

 

[Varmint Hunter]

I've had problems with protruding primers. I cant remember which primer I was having the problem with but changed to CCI and have no problems since.

I thought of that too so I picked up some Rem 9.5M and Win WLRM primers.
The Rem's measured .129" and the Win's measured .130", give or take a half thousandth of an inch.

I didn't try to seat either of them because they are actually taller then the Federals.

 

[Mike 338]

I'd seat a few and stand the case on end just to see what happens. You can always pop them out. I don't know anything about primer construction but there may be some "crush" designed into primers. At least thats what it feels like when I use a Lee Priming Tool. The primers I was having problems with were protruding 100% of the time and after switching (CCI's), I had 100% no problems.

 

[D.ID]

I use the cci without problem. Just measured my uniformer at .131 and a cci250 at .126

 

[Varmint Hunter]

I use the cci without problem. Just measured my uniformer at .131 and a cci250 at .126

That would put your measurements right about where mine are. The fact that the primer cup protrudes when all the measurements indicate that they shouldn't is what's baffling.

I'm wondering if the primer may be getting taller as its swaged into a narrow pocket. This might explain what is happening but I have never seen this in 35 years of reloading. Hmmmmmmm

 

[winmag]

I'm far from an expert, but just for comparison sake, have you tried seating your primers with a hand priming tool, & comparing the two methods?

I kinda lean towards the theory mentioned earlier about a certain amount if "crush fit" possibly being involved in the actual seating. I know it's strictly theory, & no one is advocating, or implying to use excessive force of any kind while seating primers, but it makes sense if you think about it for a while.

 

[AZShooter]

Pull down the sliding primer cup on end the RCBS priming arm to expose the piece that does the primer seating. There will be a small hole running through it. Run a small rod through the hole and tighten the seater rod. ( I use a jeweler's screwdriver) Every so often I notice high primers and this is the fix.

 

[Varmint Hunter]

Pull down the sliding primer cup on end the RCBS priming arm to expose the piece that does the primer seating. There will be a small hole running through it. Run a small rod through the hole and tighten the seater rod. ( I use a jeweler's screwdriver) Every so often I notice high primers and this is the fix.

Thanks for the tip AZ. I previously removed and reinstalled the plunger, looking for a problem at that point. The parts have been in constant use for decades and need to be replaced. I just ordered a new priming arm and plunger/cup/spring.

While I can't see this as the problem, it is worth a try.

 

[Rem700addict]

I'm glad i'm not the only one with this problem, i'm new to reloading and thought it was a newbie problem. I've been using the win lrm primers on my .300wm and I get the same primer "raised" effect, it isn't much maybe a thousandth. My primers are measuring .130 and pockets on my Rem cases are .130 deep as well. I had an old once fired case that I hadn't pulled the primer out yet and I sat it on it's primer end and it had wobble as well. I'm wondering if it could be the Rem brass as well. My question is will this be unsafe to shoot, there's not an excess protrusion? The other thing I was wondering is will it flatten the primer when shot and look like a round loaded with excessive pressure?

 

[Joe King]

I've got the Lee hand primer, it leaves them protruded a bit, I've also go the press mounted Lee safety prime which I don't really care for that much. Good idea but but like a lot of Lee stuff quality leaves something to be desired. what I'll do is seat em with the hand tool then go back and SEAT them with the press mounted priming ram, takes a bit longer and you have to develop a feel for it so you don't crush your primers but it works to get them at least flush with the case head.

Rem700addict
I've never had a round discharge or fail to discharge due to a primer protruding a little, so from that stand point I don't think it's a safety issue. OTOH I just can't get warm fuzzies from my primers sticking out from my case head and it just does not seem safe to me. Besides it's a total PIA if you want to measure COAL.

 

[Mike 338]

It hasn't been mentioned yet but see what the manufacturer has to say. They may be no help at all but it's just a phone call.

 

[D.ID]

Have you used that particular pocket uniforming tool on other brass successfully (without this problem)? I can't hep but wonder if it is cutting a flat bottom in the primer cup. Press ram loose would actually bottom out sooner unless it was so loose as to cause misalignment. I am looking at my rockchucker and can't see how that ram tip could ware at all. Have you checked the tools cutting width to confirm she is in spec. My measurements so far are the same as yours give or take, I have the same tools. with my dillon, rock chucker or hand prime I'm getting .005 recess of a seated primer with the harder cci primers and .004 with feds. If your press is clean, something has to be outright defective: brass primers or uniformer? All things considered I personally would not be comfortable trying to use rounds with ANY protrusion of the live primer. That is why I got hooked uniforming pockets it the first place, not cool. Still baffled and unable to help, just thinking out loud here and looking forward to hearing a resolution.