Primer seating depth

[BoydAllen]

I guess it all comes down to what single attribute you want primers seated to.
For me, it's preload (crush), which is not any single measure, and impossible by feel.

That last remark made me smile, since I know hall of fame members and record holders who seat by feel.

 

[mikecr]

Then I suppose they didn't need same primer preload to shoot well..

 

[BoydAllen]

Then I suppose they didn't need same primer preload to shoot well..

Checking the depth of some of my primers in a set of sized primed cases the depth was pretty consistent. IMO guys get hung up on this without verifying that seating by depth offers an advantage. As I said, seating by feel is by far the most common approach in the sport that produces the smallest angular dispersion. On the other hand I am completely lacking in long range benchrest experience, and I know that there are things that matter for that that do not for shorter distance competition, I simply do not know if this is one of them. What I do see is fellows who do not shoot the longest distances doing things that I know do not matter at short range, like worrying about ES. Short range competitors tune by looking at their targets.

 

[BoydAllen]

After I wrote my previous post, I remembered something from a while back that comes from an excellent source on long range benchrest. I made sure by searching and finding the post. Alex Wheeler has written that he seats primers by feel. Badaboom!

 

[mikecr]

Are you implying that seating by feel cannot be improved on?
That seating to same crush hurts results?

I am not a competitor, nor a youtube star. But I have tested to find that results improve for certain primers at specific crush values. This, with the striking from my guns, and hunting capacity cartridges.
I have also tested to find that striking itself can be optimized to certain primers, and this was really big to results. Kelby demonstrated that a hitch in striking, as seen via lock-time measure messes with results. And there has been testing to show that in some cases it's best not to mess with flash holes.
It seems a lot to ignore all together.

Checking the depth of some of my primers in a set of sized primed cases the depth was pretty consistent.

Depth is not crush.
What do you think your crush is by feel?
It's easy to feel primers bottom with any decent seater. But going another 2thou, or 4thou, for desired crush is not something done by feel, anymore than you could do with bullet seating or shoulder bumping..
It's something you watch happening with an indicator.

 

[jimmymac]

Pretty sure Wayne Campbell won the Tackdriver today besting a field of highly competitive shooters. I wonder if he concerned himself with primer crush as he used his hand held priming tool over the last couple days while he was kicking everyone in the behind. Good grief. It’s white noise and so far down the list of shit to worry about that it almost falls off the bottom of the page. Missing a letup, a pickup up or direction change is what matters.

Most people couldn’t even test this stuff because they don’t have the equipment and/or the skills to see the difference. Just my opinion. YMMV

 

[quest450]

I don't shoot short range, never did BUT it seems to me like short range shooters worry about wind and wind flags waaaaaaay more than 600 or 1K benchrest shooters
I hardly pay any attention to wind or wind flags, shoot your last two sighters and go to the score target and send them.

 

[JFrank]

I cannot see much difference at short range similar as to @jimmymac posts however, it’s pretty easy to test primer seating at longer range. I have’ and find a decent window and have the targets that prove the results to myself. I’m nowhere near the skill level of the top LR guys like @quest450 so for me I need to look at everything I can that may help reduce as many variables as I can.

 

[BoydAllen]

I don't shoot short range, never did BUT it seems to me like short range shooters worry about wind and wind flags waaaaaaay more than 600 or 1K benchrest shooters
I hardly pay any attention to wind or wind flags, shoot your last two sighters and go to the score target and send them.

I would understand more about long range if I shot it. As it is, I pay close attention to what top shooters have told us in forums, and when I have interviewed them for articles. In the same way, perhaps you would understand short range group if you shot a match, just to find out what its reality is. In that game the overall winner of a two day, two gun (two rifle classes) match is determined by who has the lowest average group size from 20 individual matches, each of which consists of five shots for record, and unlimited sighters that may be taken at any time during the match. Unlike long range, we can see where each shot impacts the target, and with all of the information that an entire field of flags provides, we have a lot of information to process. If we were to just pick a time and rapidly shoot all record shots for every individual match, unless conditions were very unusual, we would never win a competition. That is the reality of short range group benchrest.

 

[Dave M.]

Hmmm??? So, what do you do when the primer pockets are .130" and the primers measure .126"?

Or, does it matter?

None of the brass I’ve ever shot has pockets that are .130” out of the box. If they did and the primers truly measured .126” I would not uniform the pockets and seat them until they were fully seated at approx 5-6 thou recessed. The important point would be to make sure they are all seated the same amount (recessed the same amount). 6 thou recessed is excessive though and I would be concerned about lack of firing pin protrusion to fully ignite the primer.

 

[Dave M.]

That last remark made me smile, since I know hall of fame members and record holders who seat by feel.

I always seat by feel. I measure and can hold all primers recessed to +/-0.00075 (or more simply, to about a 1.5 thou range).
Dave

 

[memilanuk]

None of the brass I’ve ever shot has pockets that are .130” out of the box. If they did and the primers truly measured .126” I would not uniform the pockets and seat them until they were fully seated at approx 5-6 thou recessed. The important point would be to make sure they are all seated the same amount (recessed the same amount). 6 thou recessed is excessive though and I would be concerned about lack of firing pin protrusion to fully ignite the primer.

Isn't firing pin protrusion generally somewhere around 50 thou, give or take?

 

[Straightshooter1]

None of the brass I’ve ever shot has pockets that are .130” out of the box. If they did and the primers truly measured .126” I would not uniform the pockets and seat them until they were fully seated at approx 5-6 thou recessed. The important point would be to make sure they are all seated the same amount (recessed the same amount). 6 thou recessed is excessive though and I would be concerned about lack of firing pin protrusion to fully ignite the primer.

I only asked because you stated an absolute: "Primers should ALWAYS be recessed 1-4 thousandths" and though you've not "ever" shot brass with pockets like that, it's not really that unusual. Just look at what I found with some virgin Peterson 6.5 PRC LRP brass when comparing them to a box of Lapua virgin brass:

I use an Accuracy One primer pocket measuring tool so that I can quickly and accurately measure new boxes of brass that I acquire. And last year I picked up a couple more boxes of this Lapua brass (two different lots) and each lot had different primer pocket depths (like, one was at .123 and the other .125, of course there were some with a little variance in each box, but that's to be expected). With such variances and seating them all to "1-4 thousandths" from flush isn't the thing to do if one is trying to get the primer seated against the bottom of the pocket properly. This is why I like to measure things so that I'm not guessing.

Seating by feel works for many shooters and no doubt is works for most shooting disciplines. I'm not sure if it works well for the highest level of shooting. I agree with you that it's important to be seating them all the same. But, I haven't found seating by feel does that well at all. So, I measure everything in an effort to be as consistent as possible. Whether or not that makes a difference in my results is not as important to me as simply knowing that I've taken measures to removed this issue from the equation as much as possible when trying to figure out why my results might not be what I'm expecting.

 

[Dave M.]

I only asked because you stated an absolute: "Primers should ALWAYS be recessed 1-4 thousandths" and though you've not "ever" shot brass with pockets like that, it's not really that unusual. Just look at what I found with some virgin Peterson 6.5 PRC LRP brass when comparing them to a box of Lapua virgin brass:
View attachment 1491623
I use an Accuracy One primer pocket measuring tool so that I can quickly and accurately measure new boxes of brass that I acquire. And last year I picked up a couple more boxes of this Lapua brass (two different lots) and each lot had different primer pocket depths (like, one was at .123 and the other .125, of course there were some with a little variance in each box, but that's to be expected). With such variances and seating them all to "1-4 thousandths" from flush isn't the thing to do if one is trying to get the primer seated against the bottom of the pocket properly. This is why I like to measure things so that I'm not guessing.

Seating by feel works for many shooters and no doubt is works for most shooting disciplines. I'm not sure if it works well for the highest level of shooting. I agree with you that it's important to be seating them all the same. But, I haven't found seating by feel does that well at all. So, I measure everything in an effort to be as consistent as possible. Whether or not that makes a difference in my results is not as important to me as simply knowing that I've taken measures to removed this issue from the equation as much as possible when trying to figure out why my results might not be what I'm expecting.

I only asked because you stated an absolute: "Primers should ALWAYS be recessed 1-4 thousandths" and though you've not "ever" shot brass with pockets like that, it's not really that unusual. Just look at what I found with some virgin Peterson 6.5 PRC LRP brass when comparing them to a box of Lapua virgin brass:
View attachment 1491623
I use an Accuracy One primer pocket measuring tool so that I can quickly and accurately measure new boxes of brass that I acquire. And last year I picked up a couple more boxes of this Lapua brass (two different lots) and each lot had different primer pocket depths (like, one was at .123 and the other .125, of course there were some with a little variance in each box, but that's to be expected). With such variances and seating them all to "1-4 thousandths" from flush isn't the thing to do if one is trying to get the primer seated against the bottom of the pocket properly. This is why I like to measure things so that I'm not guessing.

Seating by feel works for many shooters and no doubt is works for most shooting disciplines. I'm not sure if it works well for the highest level of shooting. I agree with you that it's important to be seating them all the same. But, I haven't found seating by feel does that well at all. So, I measure everything in an effort to be as consistent as possible. Whether or not that makes a difference in my results is not as important to me as simply knowing that I've taken measures to removed this issue from the equation as much as possible when trying to figure out why my results might not be what I'm expecting.

Sorry. Maybe I should have been more clear. I was speaking strictly of SRP pocket brass. I understand LRP primer pockets are typically deeper. I think you can be very accurate and successful seating by hand. I have never loaded with the CPS setup but I’d really like to try it. I’m just unsure whether it’s worth the $6-750.
I’ve won state championships seating by feel and I think shooting a 600-39X on day 1 of the 1000 yard F-Open state championship qualifies near the highest end of accuracy.
Dave