getting primers properly seated

[Beemer-mark]

There is no such thing as seating a primer too deep. Seat firmly until they stop. If you have any adjustability in your priming device re: seating depth, ensure full-depth setting.

ditto. The primer pocket is a SAMMI dimensional depth to ensure all primers go bang. The real concern is primers not seated below the rim face. In a semi-auto they tend to make a full auto. In a revolver they'll bind the cylinder if two high. If your getting light strikes it's a problem with the gun.

 

[ReloadforFun]

Too deep is where the anvil tip is pressed close to or against the primer cup. This no to little bridge height leaves little to no priming compound to be crushed between the indent and the anvil.

Generally, if the primer cup is 0.010" or deeper to the case, you are seating too deep.

 

[BLUEDOT37]

It's not rocket science

Primers can be seated too deep, but not seated deep enough is the more common problem.

Too deep is where the anvil tip is pressed close to or against the primer cup. This no to little bridge height leaves little to no priming compound to be crushed between the indent and the anvil.

"Completely seated" is defined as the primer anvil legs being against the bottom of the primer pocket. If they are not against the bottom of the primer pocket, the firing pin force is weakened moving the entire primer deeper instead of indenting the primer cup.

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Your last quote is correct.

I don't know how you can be too deep.

Primer pockets are not all identical in deep.

If the primer is seated to the bottom of the pocket (no matter how deep it is) the anvil's legs (which stick out a bit before seating) will be even with the bottom for the primer cup which is flat on the floor of the primer pocket.

The worse you could do is crush it & I, nor my heavy handed son's, have never done that.

The anvil's small tip contacts the primer cup & priming compound to sensitize it & stops with the primer/anvil legs on the floor of the primer pocket.

I've used an Universal Primer Arm on my RCBS JR3 press for priming since the mid '70s & have done tens of thousands without issues.

Seat the primer until it contacts the seat & firmly stops. Period.

Some primers will be just .001" below flush & some will be .005"- .008" below flush. (SAAMI specs say a max of .008" below flush.) They all go BANG!

As you remove the primed case from the shellholder swipe the tip of you index finger over the seated primer to check for high/irregular primers.

Double check/re-seat any that feel odd.

.

 

[ReloadforFun]

I'll end since this seems to be becoming and argument. That is not my intention. My comments are based on investigations done by a primer manufacturer.

Primers are extremely reliable. Problems are rare generally, and the first thing to check is always if they were completely seated. Not completely seated is, by far, the primary cause of problems. Everything else is a miniscule portion of an already small problem.

Have fun. Shoot a bunch.

 

[gwpercle]

Guys, this is all great info. So thanks to everyone that posted.

I am thinking about getting a ram primer since I have the MEC Marksman press, probably the RCBS ram.

Is there a better way to put the primers in the ram than by hand with fingers or even tweezers?

I watched a number of YouTube videos demonstrating the ram primers and they all just use their fingers to put a primer in the ram. I would have thought there would be a dispenser that works with the primer pick-up tubes (or something) , still manual, that dispenses a primer into the ram. I have looked but haven't found anything obvious.

After 50 years of priming ... Fingers are the best tool !
We were told picking up a primer would "kill" it ...that's Fake News / primers are a lot harder to kill ... thumb and forfinger are still best . Primer feed tubes still have to be loaded and they like to disgorge their contents all over the floor and bench .

One of the best priming systems is a Lee Hand Press , Lee Ram Prime mounted in it and your thumb and index finger .
Put primers in a round shallow container so you can slide one to the edge and pick it up ... mine is a small coffe cup saucer .
Gary

 

[mikld]

Hint when using a ram prime and picking up primers; dump primers on a sheet of paper towel, Much easier to pick up. Don't worry about finger "contamination". Unless your fingers are dripping oil, the primers won't be harmed. I have been a machinist mechanic most of my life and my fingers show it. Using a paper towel I can easily pick up a single small primer with my "sausage fingers"...