My primer seating method

[wvlongshot]

I understand primer pockets to same depth. But all the priming tools hold the case by the rim, has anyone checked the + or - of rim placement on the brass in regards to case head?

 

[Dusty Stevens]

I understand primer pockets to same depth. But all the priming tools hold the case by the rim, has anyone checked the + or - of rim placement on the brass in regards to case head?

Yes and it varies. Good brass not so much but short of cutting them all, throw out the outliers, and stay within that accuracy window of crush

 

[Tesoro]

My 450m dont have legs. I use tthe 21c and on 6br lapua I get .004 below case head and then thats it. Not really anything to crush ? Those primer cups are tough.

 

[mikecr]

Crush is tied to pocket depth, rim thickness, and actual primer height.
Save yourself all the hassle and get an indicated K&M (which accounts for all 3 matters).

 

[Bronsin]

^^^^^^Beat me to it.

 

[Tesoro]

I think crush is an antiquated word for modern reloading.!

 

[LC Tikka]

Crush is tied to pocket depth, rim thickness, and actual primer height.
Save yourself all the hassle and get an indicated K&M (which accounts for all 3 matters).

Good to see there are some thinkers out there. Exact pockets are not really part of it, shouldn't primer depth be set off the case shoulder to obtain an even length and consistent strike from the firing pin.

 

[Fern]

I have the frankford hand primer and was trying to figure out a way to set it up quickly before priming. What you did there looks like it could work as well.
I tried to test the rcbs hand primer and press primer to get reading across them.

 

[Dusty Stevens]

Doesn’t the K&M with the gage just measure pressure applied to a seated primer ?

No it takes into account depth of pocket and height of primer and gives you a variation reading. I auctioned one off on here a few years ago

 

[JFrank]

No it takes into account depth of pocket and height of primer and gives you a variation reading. I auctioned one off on here a few years ago

Yes I recall that auction although no personal experience with that tool, I thought to ask.
Thx

 

[GLO123]

I must be doing it all wrong. I clean, trim, chamfer the pockets. Then just use my RCBS universal hand primer and install the primer below flush. I don’t measure anything as far as primers go. Just below flush.

 

[Dusty Stevens]

I must be doing it all wrong. I clean, trim, chamfer the pockets. Then just use my RCBS universal hand primer and install the primer below flush. I don’t measure anything as far as primers go. Just below flush.

What if your firing pin drives your primer forward .010 before it goes off? And what if the next one moves .015? Just going below flush may or may not be sensitizing or oversensitizing the pellet

 

[rwj]

What if your firing pin drives your primer forward .010 before it goes off? And what if the next one moves .015? Just going below flush may or may not be sensitizing or oversensitizing the pellet

I just wish my shooting was good enough to notice the difference! I’m thinking that you know you’ve made it to the top when weight/height sorting primers makes a noticeable difference… hoping I too can arrive there someday!

 

[L W P]

I have found that the old K&M steel adjustable primer tool works great. Seating primers by feel like people have told me (Tony Boyer and others of the same shooting level) works great. I never square pockets on virgin brass but will lightly after each firing from then on by hand. Mostly just removing the carbon from the bottom of the pocket wall/floor junction.

 

[Henryrifle]

@Dusty Stevens: Thank you for bringing this topic up and thanks also to @mikecr and @wvlongshot for pointing out some important detail. Realizing this is not an equipment discussion, I recently picked up a primal rights competition primer seater. Great build quality but unless you use it in a way that lets you “feel” the primer bottom, you will not get consistent crush due to the relationship between the extraction rim and primer pocket depth. It’s interesting to me that with more experience, I find the original ways of priming (hand priming) are better from an accuracy perspective as long as you understand and can repeat the “feel” consistently.

 

[mikecr]

You cannot set a specific primer crush with feel.
It has to be measured to know.

For hunting capacity cartridges, this crush setting and every aspect of striking, makes a difference.
I don't know why. Logically, if it goes off the results should be the same, but there is a lot more to it for results to be the same.

 

[INTJ]

I have been using the K&M Primer Gauge for a while now. It allows seating each primer to an exact crush in its specific pocket. It saves having to measure each pocket depth and each primer cup height.

I haven't yet experimented with varying seating depths. I seat SR primers with .002" crush and LR primers with .003" crush. I do intend to do do some tuning with primer crush.

I also wonder if sorting cases by primer depth is worthwhile to test. Getting an exact crush seems to be the main thing, but making sure the firing pin fall to the primer is exactly the same might be worthwhile also.

I find up to .004" to .005" variance in primer cup height/pocket depth. I suspect that our uniformed pockets have a little variation, and I know primer cups vary in height.

 

[Coyotefurharvester]

For me the Fed srp is the easiest primer to feel and get a 0.003-4 crush, I can't get a crush with 450's or 7.5 with my Lee hand primer. I just tried some Fed AR match for the first time, surprised me how easy it was to get 0.003 past the actual primer pocket depth. Trying them in my 20p upper.

 

[Bronsin]

I have been using the K&M Primer Gauge for a while now. It allows seating each primer to an exact crush in its specific pocket. It saves having to measure each pocket depth and each primer cup height.

I haven't yet experimented with varying seating depths. I seat SR primers with .002" crush and LR primers with .003" crush. I do intend to do do some tuning with primer crush.

I also wonder if sorting cases by primer depth is worthwhile to test. Getting an exact crush seems to be the main thing, but making sure the firing pin fall to the primer is exactly the same might be worthwhile also.

I find up to .004" to .005" variance in primer cup height/pocket depth. I suspect that our uniformed pockets have a little variation, and I know primer cups vary in height.

I use the same tool and found that my "feel" with other tools was far more than .002 crush. When I uniform primer pockets, it's with the Sinclair tool that always cuts to a fixed depth. You can always sort primers according to their height to control that variable as well.

 

[INTJ]

I use the same tool and found that my "feel" with other tools was far more than .002 crush. When I uniform primer pockets, it's with the Sinclair tool that always cuts to a fixed depth. You can always sort primers according to their height to control that variable as well.

I have used many primer pocket cutters and currently use the K&M. Since I use the K&M Primer gauge I don't have to measure pockets or cups, but I am suspicious that a cutter spinning in a drill is going to cut pocket depths to with better than .001" variance by indexing off the case head. How hard we hold the case could cause that much variance.

I do agree that the K&M Gauge does show
how inconsistent our feel is. A tight pocket takes more force than a looser pocket to get the same crush.