Primer Seating Depth, How Much Do You Care?

[INTJ]

Cool, thanks, sounds good

You just have to experiment and see what works for you.

 

[JFrank]

@INTJ
I may try one of those gages one day when I find an extra $160 laying around and I want to trim my groups a tad more, I use a K&M uniformer preset at .122 , a regular K&M. PT and now. a 21st century click adjustable. They seem to give a very feel for seating primers , I did not shoot any screamer groups this year but I don't think primers were the cause.

 

[BartsBullets]

Touch the bottom and stop.

Bart

 

[INTJ]

@INTJ
I may try one of those gages one day when I find an extra $160 laying around and I want to trim my groups a tad more, I use a K&M uniformer preset at .122 , a regular K&M. PT and now. a 21st century click adjustable. They seem to give a very feel for seating primers , I did not shoot any screamer groups this year but I don't think primers were the cause.

Jim,

I think most guys use a tool with good feel and do very well. For me personally, I trust what I see way more than why I feel.......

 

[mikecr]

They don't do well about crush -by feel.
Do a blind test with the K&M, observe result on indicator, and you'll see how erroneous feel really is.

 

[INTJ]

They don't do well about crush -by feel.
Do a blind test with the K&M, observe result on indicator, and you'll see how erroneous feel really is.

They do well by results on target, and a wide tuning node covers up a lot of these small loading errors. I just don't always get wide tuning nodes.

As far as primer crush, I have noticed that a tight pocket makes it feel like I have bottomed when I haven't. The K&M Primer Gauge shows that very well.

Of course, I can't help but wonder if it would help sorting cases by primer depth after seating primers with the K&M Gauge. It would eliminate the .005" variance in firing pin fall between cases with the same crush.

 

[mikecr]

The window for optimum firing pin fall is unknown until tested.
I found it with one gun using 10thou increments w/inside bolt adjustments. Grouping was open, closed, and re-opened. That, with a set crush through testing.
My pockets are uniformed in depth, uncompressed primers vary in height as much as 2thou, and headspace held within 1-1.5thou.

There may be further potential in qualifying uncompressed primers by height, to force consistent crushed (as measured) primer depths(as verified), and testing for optimum pin fall with this.

With a good shooting gun & load it's easy to assume that best is reached from it.
I had my son's Cooper shooting 3/8moa at 500. Killed a lot of GHs and assumed that I was getting all possible from it. But I managed to further trim 1/8moa with no adjustment other than firing pin fall.
Had I not engaged in that testing, I would never have reached that gain, and I would have assumed striking other than sufficient wouldn't matter.

 

[YEW PLUCKER]

As long as I can feel, with the tip of my finger, the primer is slightly below flush, and the case doesn't wobble when I stand it up... I don't give it too much thought.

 

[D Coots]

Touch the bottom and stop.

Bart

What a novel idea...,

 

[MGYSGT]

Just seat them so they are not proud.

 

[rkittine]

During three sessions of the Williamsport Bench Rest School, I now sort by primer height and pocket depth and use a hand tool with a micrometer on it to get the exact crush recommended by the primer manufacturer.

Bob