Primer seating depth

[retired]

no need to measure
my primer pocket cutting tools cut to a fixed stop...not adjustable.
cut to a number in the pocket spec by sinclair.
i clean my pockets with the same tool.
my pockets are always UNIFORM.
i seat the same way every time.
as has been noted firing pins have about .060 movement.
seat to the bottom of the pocket

So you never measured?

 

[L W P]

no need to measure
my primer pocket cutting tools cut to a fixed stop...not adjustable.
cut to a number in the pocket spec by sinclair.
i clean my pockets with the same tool.
my pockets are always UNIFORM.
i seat the same way every time.
as has been noted firing pins have about .060 movement.
seat to the bottom of the pocket

OK, thanks

 

[Bart B.]

Measure primer height from top of cup to bottom of anvil.

Measure pocket depth from case head.

How far below case head must the cup be to push the anvil a few thousandths into the cup preloading the pellet inside the primer?

Do it.

If you're good with calipers, measure the anvil legs distance from the bottom of the cup. That tells you how much the primer can be seated while pushing the anvil into the primer.

Can primers be seated so the cup bottoms out in the pocket? Yes as long as the pellet isn't crushed enough to cause detonation variables.

 

[L W P]

Measure primer height from top of cup to bottom of anvil.

Measure pocket depth from case head.

How far below case head must cup be to push the anvil a few thousandths into the cup preloading the pellet inside the primer?

Do it.

OK, thanks

 

[Richard Coody]

OP ?. To the guys that say that they seat by feel. No one really has given any measurement to below case head. I get it that you guys go by feel but you could give some idea in measurement where that is. Just asking if you have ever measured the depth of your primer, in reference to after seating by feel? And from the case head. Maybe you never have measured after you seat by feel, I'm not sure.

never bothered to measure.

 

[Bart B.]

Check this out....

https://ballistictools.com/articles/primer-pocket-depth-and-diameter.php

Best info on pocket and primer specs I've seen. Do the math for a .004" anvil seat into cups. Then you'll see the spread in cup depth below case head that exists. Which is why a given depth can have a wide spread in anvil seating depth. Especially if pocket depth increases when uniformed.

If your sense of tactile feedback from the lever force on your primer seater is good, proceed...... When the resistance suddenly increases, stop seating measure cup depth then record it. Do a few more the average them. Calculate the average anvil seating depth. Use more or less force as needed.

Ain't as simple as weighing charges to 2 places.

 

[243winxb]

Crush fit for primer seating.

 

[L W P]

Crush fit for primer seating.

Nice job, Who says that there's no math to this!

 

[L W P]

Check this out....

https://ballistictools.com/articles/primer-pocket-depth-and-diameter.php

Best info on pocket and primer specs I've seen. Do the math for a .004" anvil seat into cups. Then you'll see the spread in cup depth below case head that exists. Which is why a given depth can have a wide spread in anvil seating depth. Especially if pocket depth increases when uniformed.

If your sense of tactile feedback from the lever force on your primer seater is good, proceed...... When the resistance suddenly increases, stop seating measure cup depth then record it. Do a few more the average them. Calculate the average anvil seating depth. Use more or less force as needed.

Ain't as simple as weighing charges to 2 places.

Thank you sir

 

[retired]

so all you have to do now is to measure each primer pocket, measure the primer selected.
and install.then check your work by measuring the seating depth.
or
do what i said

 

[R.Morehouse]

I uniform my pockets after FFing then my primers generally end up 7K. I measure every 5th one and that just seems how it works out. Same on the 6.5, 2 PPC's & now the BRA. Not a plan......Just the result.

Regards
Rick

 

[L W P]

I uniform my pockets after FFing then my primers generally end up 7K. I measure every 5th one and that just seems how it works out. Same on the 6.5, 2 PPC's & now the BRA. Not a plan......Just the result.

Regards
Rick

Thank you sir for the measurement.

 

[Webster]

Thank you sir for the measurement.

Do a search. This topic has been covered 10,000 times.

 

[BoydAllen]

The funny thing in this thread is the back and forth about feel and depth. It is as if the person asking for depth has never seated a primer by feel and is afraid to try it. Just as a reference point, pretty much all of the short range benchrest shooters that I am personally acquainted with, including hall of fame members and world record holders seat their primers entirely by feel. They all shoot better than we do. Take the hint and stop with the OCD stuff. Of course I understand that if you are making a serious move into 600 and 1,000 benchrest that the loading routine is different, but you had better be hitting all of the stops, every one, before you worry about this sort of thing. Most shooters that I know want to emulate only certain parts of the entire program that is required to achieve the best results. Obviously this limits their results significantly. Accuracy is a weakest link, total program thing.

 

[Laurie]

I have one particular brand and caliber of large rifle brass that will not seat below the surface of the brass. I used a Sinclair primer pocket tool to uniform the pockets. It will not cut any brass from the middle of the primer pocket, only the circumference. My Lee hand tool (old) will not seat below the brass head. The primers are bottoming out, I can feel it. How do I solve the problem? Buy another brand of primer pocket tool or get a bench mounted primer tool? This is the same for all brands of primers. Bad lot of brass?

I had the same experience with a lot of Norma 6XC brass a few years ago. The pockets were too shallow, as simple as that! No amount of changing priming tools or priming practices was going to stop them being fully seated, but still proud of the case-head. So, out came the Sinclair uniforming tool and a lot of metal was cut out of the pocket floors. Then primers seated properly.

No, I didn't measure pocket depth and compare to SAAMI or whoever's specifications - if fully seated primers (by the 'feel' method - I'm with Boyd Allen 100% on this) stand proud in a particular set of cases and those same primers are slightly below flush in other cases as they should be, then it's a fair deduction that the brass is out of spec not the primers. (I wasn't alone either as others who got these cases had identical experiences and were left wondering what they'd 'done wrong'.)

FWIW, I used to recut pockets in everything, but life is way too short! Norma (these particular 6XC cases aside), RWS and Lapua are left as the makers made them, but if it is Winchester or Hornady brass being used for any half-serious competition they'll be cut. As somebody in an earlier post said, they have radiussed floor to wall junctions and IME they nearly invariably have concave floors. Start a cut and it is the corners that lose metal first, then the outside of the floor, and the shiny area moves into the centre around the flashhole last. That's before we get to flash-hole issues, another subject in itself. I can't comment on Peterson yet - just acquired some 260 Rem and visually it looks as per Norma / Lapua / RWS.

 

[rammac]

So if you are teaching a new reloader how to seat "by feel" how do you teach them what a proper seating depth feels like?

 

[Dusty Stevens]

So if you are teaching a new reloader how to seat "by feel" how do you teach them what a proper seating depth feels like?

First you must have a priming tool solid enough to feel the anvils touch then you show them with calipers just how much .005 is and tell em to push it that much farther. Its hard to teach a feel but you can tell them what to feel for

 

[243winxb]

So if you are teaching a new reloader how to seat "by feel" how do you teach them what a proper seating depth feels like?

Let them try to damage a primer like this while seating it. Takes a RCBS press to cam over, using a ram prime unit.

Not easily over done when seating a primer.



Had a few fire when smashed like this in 45 acp. The military crimp was not remove enough.

 

[rammac]

First you must have a priming tool solid enough to feel the anvils touch then you show them with calipers just how much .005 is and tell em to push it that much farther. Its hard to teach a feel but you can tell them what to feel for

Which is actually my point, you can't teach proper primer seating without some kind of dimensional data, you can't just tell a novice to simply press a primer in to the pocket until the anvil seats, they don't have any idea how that feels and with a press you wont even be able to feel the anvil seat. If you do some research you'll find that all primer manufacturers recommend that the primer cup be seated to at least .002" below flush and most use a range of depths of .002" to .004" with some recommending as deep as .008". The cup must be below flush in order to set the anvil at it's proper place, too shallow and the primers can be insensitive due to not enough energy being transferred to the mix, too deep and the primers can be insensitive due to the mix being crushed and pushed away from the anvil/cup contact area.

 

[Dusty Stevens]

Which is actually my point, you can't teach proper primer seating without some kind of dimensional data, you can't just tell a novice to simply press a primer in to the pocket until the anvil seats, they don't have any idea how that feels and with a press you wont even be able to feel the anvil seat. If you do some research you'll find that all primer manufacturers recommend that the primer cup be seated to at least .002" below flush and most use a range of depths of .002" to .004" with some recommending as deep as .008". The cup must be below flush in order to set the anvil at it's proper place, too shallow and the primers can be insensitive due to not enough energy being transferred to the mix, too deep and the primers can be insensitive due to the mix being crushed and pushed away from the anvil/cup contact area.

I feel certain we're trying to say the same thing except i'm asking which lot of which brand primer needs to be set at .008"? which lot needs to be set at .004"? measuring primer depth and saying thats the end all is like setting a bullet by a comparator and always putting it there.