Primer Seating Depth

[Pres100]

Better picture

 

[King2506]

I recently watched

and

The conclusion seamed to be that seating primers 9 thousandths below flush was close to optimal

Which tools does the group here think are capable of seating primers consistently to 9 thousandths below flush consistently with a reasonable margin of error?

What's an acceptable way of measuring how far below flush the primer is seated? Could this be accomplished with the depth gauge on quality calipers or would different equipment be needed for this measurement?

I just bought the primal rights cps primer seater and love it! Works very well but it’s pricey

 

[thestoicmarcusaurelius]

Precision Primer Gauge

The Precision Primer Gauge takes precision measurements of primer pocket depth and the depth of seated primers in relationship to the face of the case head.

bullettipping.com

Super Precision Click Head Bench Rest Priming Tool (Priming Tool and shell holders: Super Precision Priming Tool with #1 Shell Holder)

All our products are made in the United States.

21stcenturyinnovation.com

The Precision Primer Gauge looks like a great tool.

I still think that the test was based off of the measurement between the case head and the primer.

For the more experienced BR and F-Class guys, have y'all noticed that this 7 thousandths to 9 thousandths from flush with the case head to the primer is in general a good range or does this vary a decent amount from one load to the next?

 

[Okumacaptain]

The Precision Primer Gauge looks like a great tool.

I still think that the test was based off of the measurement between the case head and the primer.

For the more experienced BR and F-Class guys, have y'all noticed that this 7 thousandths to 9 thousandths from flush with the case head to the primer is in general a good range or does this vary a decent amount from one load to the next?

Pretty sure the majority of the guys that I shoot matches with are using a hand held and seat primer as far as it will go and call it a day .

 

[6bra1k]

to be clear, there is only ONE seating depth
THE BOTTOM OF THE PRIMER POCKET,
and then a small crush...
play all the numbers games you want,
uiform your pockets and seat to the bottom with a small crush

 

[Surgeonwithagun]

Flush with the face of the case head if my hand primer will give it to me. If not, deep enough to function in the weapon.


John

 

[mikecr]

If all you want is primer firing then just seat em all to bottom.
If you want best precision, in a hunting capacity cartridge, you'll seat to exactly 2-5thou crush (depending on brand). That's not a generalization, but for each and every primer (they vary in height) to each individual cup (they vary in depth with more/less firing).

This has nothing to do with a depth below casehead

 

[Ron-S]

I recently watched

and

The conclusion seamed to be that seating primers 9 thousandths below flush was close to optimal

Which tools does the group here think are capable of seating primers consistently to 9 thousandths below flush consistently with a reasonable margin of error?

What's an acceptable way of measuring how far below flush the primer is seated? Could this be accomplished with the depth gauge on quality calipers or would different equipment be needed for this measurement?

 

[Ron-S]

I recently watched

and

The conclusion seamed to be that seating primers 9 thousandths below flush was close to optimal

Which tools does the group here think are capable of seating primers consistently to 9 thousandths below flush consistently with a reasonable margin of error?

What's an acceptable way of measuring how far below flush the primer is seated? Could this be accomplished with the depth gauge on quality calipers or would different equipment be needed for this measurement?

9 thousandths below flush seems like a lot to me. Two or three seems more reasonable. But to do that you need a primer pocket deep enough to allow the primer to seat and bottom out that deep without crushing. That's where "uniforming" primer pockets may become necessary. With once fired military brass I've found that to be a common necessity. You definitely don't want primers protruding out.

 

[Straightshooter1]

9 thousandths below flush seems like a lot to me. Two or three seems more reasonable. But to do that you need a primer pocket deep enough to allow the primer to seat and bottom out that deep without crushing. That's where "uniforming" primer pockets may become necessary. With once fired military brass I've found that to be a common necessity. You definitely don't want primers protruding out.

It really depends on the depth of the primer pockets. Not all head stamps have primer pockets are the same depth. For example, my 6.5 PRC brass having LR primers, Hornady brass and Peterson brass have primer pockets that are at .129", but my Lapua brass is at .125". Then, there's the issue of variance in primer cup heights from one brand to another, like Federal being .117" and CCI at .118" and Remington at .119". My Federal primer's height, including the anvil, measures .126-.128". For my Hornady and Peterson brass I seat the Federal primers .009" below flush to get a slight crush on the anvil as you can see with the difference between the over all height and the cup height. And though they're that deep, they fire just fine in my particular guns and I get pretty good results. I do think that in some guns, they may not have a firing pin that'll reach long enough to get a good strike at .009" below flush.

 

[Webster]

Better picture



View attachment 1304083

How many thou does the anvil protrude above the cup edge? Is this the limit of crush? You cannot push it deeper than the cup edge.

 

[mikecr]

I do think that in some guns, they may not have a firing pin that'll reach long enough to get a good strike at .009" below flush.

That would be a bad striking setup for sure. By default released pins protrude 50-60thou, but they'll fire just fine under half of that. Our headspace should be no more than ~2thou, so add 9thou under flush, and there is plenty of pin strike still.
It really takes a lot of bad effort or something broken to cause primer misfires.

 

[BartsBullets]

to be clear, there is only ONE seating depth
THE BOTTOM OF THE PRIMER POCKET,
and then a small crush...
play all the numbers games you want,
uiform your pockets and seat to the bottom with a small crush

^^^^^^^
Everyone would do well to listen to what 6bra1k is saying.

Bart

 

[Sixgun]

I recently watched

and

The conclusion seamed to be that seating primers 9 thousandths below flush was close to optimal

Which tools does the group here think are capable of seating primers consistently to 9 thousandths below flush consistently with a reasonable margin of error?

What's an acceptable way of measuring how far below flush the primer is seated? Could this be accomplished with the depth gauge on quality calipers or would different equipment be needed for this measurement?

Premium Carbide Primer Pocket Correction Tool | Reloading

Premium Carbide Primer Pocket Correction Tools for reloading allow you to consistently square the primer pocket bottom and clean out carbon deposits.

kmshooting.com

This will always maintain your primer pocket if you use it in your cleaning process...awesome job chipping the carbon out. You can adjust the depth....if you if fact clean pockets.

 

[BoydAllen]

Repeating myself, I am pretty sure that the most proficient shooters of groups at 100 and 200 yard seat their primers by feel. I know that many are bound and determined to make this a lot more complicated, but ask yourself at those distances do they shoot better than the group that I mentioned?

 

[Sixgun]

It will only clean pockets .122 deep or less, many

 

[Sixgun]

A BR4 is .1125 + .009 below flush = .1215. Yes, it mostly just cleans them out as most of the cases are .002 -.005 deeper as least the ones i measured...but every once in a while it trues the bottom of the pocket on a shallow one.

 

[calgarycanada]

I’m pretty sure, when you crush primer 9 thou(which is a lot), lot of that crush is coming from deformation of primer cup rather than anvil getting seated deeper into cup. If anvil goes so deep into cup that it’s flush with cup itself, something has to give. Primer compound is solid which can be compacted some but can not be compressed much.
1 to 3 thou anvil movement into cup (ie compression of primer compound)is reasonable but beyond that only two possibilities are:
(A) Anvil breaks into primer compound, displacing some of it. Can be seen as powder residue if you unseat unfired/live primers after seating with lot of crush.
(B) Cup(which is soft material) gets deformed. It can be seen from shape of cup compared to unseated/new primer.

Stop buying into hype and seat with feel to bottom out the primer and do not crush the chit out of it.

 

[mikecr]

Anyone crushing primers 9 thou is going out of their way to mess it up.
It would 'feel' pretty bad, even as inaccurate as feel is.

 

[BoydAllen]

In this thread I see a lot of conjecture presented as if it was fact, with no supporting evidence. This is why I tell those new to benchrest not to spend too much time reading on the internet, lest they become confused. My recommendation is that they attend matches and pay close attention to what they see. (speaking here specifically of short range group)

Recently when I posted a link to an article about an insanely small unlimited agg. someone essentially said that it was luck. For those that are not familiar, an agg, in short range group consists of the average group size (at 100 yards) of five five shot matches, a total of 25 shots fire for record. The shooter seats his primers by feel, as do most of the short range group shooters that I know. This group includes Hall of Fame members and record holders.

Of all those who have posted in a couple of threads on this subject, to my knowledge, I am the only one who contacted a manufacturer to find out what they recommend.

A while back in a conversation with a very successful gunsmith who is known for the success of the long range rifles that he builds, he told me that based on his measurements that typical pin protrusion from the bolt face into a fired small rifle primer is around .028. Given that the standard for FP protrusion is .050 to .060, I cannot understand how anyone can come to the conclusion that primers seated far enough to have the anvil legs flush with the bottom of the cup would risk not firing in any rifle with FP prutrusion that is within mfg. spec.

Then there are those who speak of "crushed" primers. I would like to know what actual research they have done to determine that this happens in cases where the primer is seated deeper than they approve of, that have no visible deformation.