Opinion on primer seating? What is your depth?

[katakenm]

I've been reloading since 1988. Never have I gotten a clear and definitive answer or have I had results of my own reloading show that primer depth varies my ES, SD, or produced erratic velocities. I use a Lab Radar and hold some pretty strict practices. So relevant history on my current "work-ups". I have beena 308 Win and 30-06 reloader for 30 years, currently I am using Peterson Brass for my 308 and have moved to 338 Lapua for a recent rifle. Since I started with Peterson Brass on the 308 a few years ago I have purchased 338 LM in, Peterson, Norma, Lapua, Hornady, and have my once fired PPU brass from 100 once fired from my rifle and another 100 Winchester once fired from my rifle. I have several reloads I've been up and down with and my best load is the Peterson with IMR 7828, FGMM Magnum primers, and Siera 250gr BTHP. I'm holding a 1/2 MOA out of a Ruger Precision Rifle. So heres the question, I never really had a primer pocket want to go more than a hair beyond flush with any of the 338 brass until I purchased brass from Graf's, they call the brass Kinetic "match brass" and my first primer sank silly low. Any feed back on Kinetic Brass and also on primer pocket depth regardless of cartridge being used? I seat with a RCBS hand primer to "finger feel" and have learned how to become very consistant at it. But sinking one low vs. flush, what are your thoughts? Thanks.

 

[bpcrshooter]

I have always used a primer pocket uniformer and seated primers fully, that way they ARE all the same. If the primer pocket was too deep from the factory I set those aside and used them for fouling or plinking. If your firing pin has to use energy to seat the primer you may get inconsistent ignition.

you will have diferances between manufactures...., alloy thickness, etc. But that is why we try and use the same brand with the same lot, toget uniformity.

 

[rsmithsr]

THE ANSWER
to the bottom of the pocket and a light crush in place..aprox .002

 

[Bob Wright]

I have always used a primer pocket uniformer and seated primers fully, that way they ARE all the same. If the primer pocket was too deep from the factory I set those aside and used them for fouling or plinking. If your firing pin has to use energy to seat the primer you may get inconsistent ignition.

you will have diferances between manufactures...., alloy thickness, etc. But that is why we try and use the same brand with the same lot, toget uniformity.

Yes, uniform them and seat them the same. The uniforming tool can wear over time. So, occasionally check primer seated depth. Different primers vary on seated depth.

 

[aushunter1]

I have always used a primer pocket uniformer and seated primers fully, that way they ARE all the same. If the primer pocket was too deep from the factory I set those aside and used them for fouling or plinking. If your firing pin has to use energy to seat the primer you may get inconsistent ignition.

you will have diferances between manufactures...., alloy thickness, etc. But that is why we try and use the same brand with the same lot, toget uniformity.

Yes, uniform them and seat them the same. The uniforming tool can wear over time. So, occasionally check primer seated depth. Different primers vary on seated depth.

I would never buy a alloy primer pocket uniformer or one made from any material that's softer than the brass.
The only uniformer I have ever bought is a Tungsten Carbide version from Sinclairs, that thing will never wear & will be here long after Im gone & still in the same condition!
@ $30 I think its cheap for something you will never have to replace..............................unless you lose it

SINCLAIR INTERNATIONAL CARBIDE PRIMER POCKET UNIFORMERS | Brownells

The Sinclair primer pocket uniformers are precision ground from one solid piece of tungsten carbide, so there is no need to worry about changing the depth of cut. These cutters are designed to be used every time you reload. They cut the depth of p...

www.brownells.com

@katakenm, I would be concerned if a primer pocket was not of SAAMI size, sure there are variances in primer cup sizes which could affect how it seats but I have never really come across brass where these is what I would call excessive low seating.

I have never heard of this brand of brass but if there is a situation where the primer is seated to deep it will obviously flow back to the bolt face. Cant say I like the idea of movement in a primer!

 

[Bob Wright]

This one, is one of the more popular choices that can slip since it's 2 pieces held together by a socket head screw. It's cutter is carbide but the collar design has failed me on a whole bunch of brass. The screw allowed the collar to slip down the cutter shank...
It was a surprise when I started seeing seating depth increase dramatically.

 

[Savage 12BVSS]

THE ANSWER
to the bottom of the pocket and a light crush in place..aprox .002

This is what I shoot for.....no pun intended.

 

[MagnumManiac]

Interesting, most primer brands require .003" crush AFTER the anvil and cup are flush with the pocket bottom.
This may result in a primer .005" below flush in some cases. .003" in another and .008" in the worst of the bunch.
Unless you measure, how will you ever know?
My primers are .003" crush, measured after the cup and anvil are touching the bottom of the pocket. Funny thing, I never found an improvement uniforming a perfectly concave pocket, only more soot in the pocket when it was perfectly flat. Groups at 600 didn't change either. Changing primer type had more influence in my testing than uniforming pockets.

Cheers.

 

[J E Custom]

If you buy good brass, the primer pocket should allow the primer to seat flush. I use the primer pocket prep tool only once if the primer is not allowed to seat deep enough. I don't want the primer to move or lose it's seal so good clean tight fitting primers that are flush are my goal.

As I am priming, I check each primer for a flush fit. If it does not fit flush, I set it aside and de prime the ones I set aside and remedy those problems. If the pocket is to deep, I discard that piece of brass
or use it for a bullet seating depth gauge without a primer in it.

I used to clean the pockets with a tool and found I was removing pocket wall and reducing primer pocket life. Now with the pin tumbler the pockets come clean with little effort and case life is better.

With that said, flush is my recommendation.

J E CUSTOM

 

[Canhunter35]

Interesting, most primer brands require .003" crush AFTER the anvil and cup are flush with the pocket bottom.
This may result in a primer .005" below flush in some cases. .003" in another and .008" in the worst of the bunch.
Unless you measure, how will you ever know?
My primers are .003" crush, measured after the cup and anvil are touching the bottom of the pocket. Funny thing, I never found an improvement uniforming a perfectly concave pocket, only more soot in the pocket when it was perfectly flat. Groups at 600 didn't change either. Changing primer type had more influence in my testing than uniforming pockets.

Cheers.

I agree, uniforming pockets never had a noticeable effect for me either, but uniforming flash holes sure has

 

[Savage 12BVSS]

I agree, uniforming pockets never had a noticeable effect for me either, but uniforming flash holes sure has

Thats the truth, don't know how many pieces of "premium brass" I have hit, punch out material and some that have pieces hanging back over the flash hole, stuff that makes a difference. I also have a lyman tool that cleans the carbon out of primer pockets (uniformer) and one that actually squares and removes bottom metal (reamer). I like the uniformer, removes carbon not brass.

 

[Canhunter35]

Thats the truth, don't know how many pieces of "premium brass" I have hit, punch out material and some that have pieces hanging back over the flash hole, stuff that makes a difference. I also have a lyman tool that cleans the carbon out of primer pockets (uniformer) and one that actually squares and removes bottom metal (reamer). I like the uniformer, removes carbon not brass.

I have the Sinclair that goes in a drill, once the brass is uniformed it cleans the carbon from the primer pocket

 

[Mikecr]

For those interested in setting primer crush as a standard (and easily) K&M makes THE seater to do this.
Through testing I came to 2thou crush for Fed/Win/Rem, and 5thou for CCIs.

 

[JJMoody]

Tagging in. My co-ax seats to .007 below case head as measured by my calipers in new ADG 7 mag brass. The manual describes-.004-.008 as the goal. I have no idea... just getting used to the new setup. Never measured this before now