Difference in primer pocket shape..!!!!

[rsbhunter]

Been reading about the debate on primer seating depth vs accuracy (yes, I have a reloading problem). Not to get involved in that debate, but I use Alpha and Lapua 6mm Dasher brass (6 br fire formed). The primers in the Alpha brass actually seem to go in the pocket with a "step" in the seating where it gets a little tighter. Using a FrankFord Arsenal adjustable primer tool set to seat primers @.007 in the Lapua brass, wont seat the primer in the Alpha brass but .002 at most. Has any of you had this experience? rsbhunter

 

[Fuj]

I uniform all my primer pockets on my match brass first, then
seat to bottom by feel.

 

[LVLAaron]

I'm not sure I understand your concern or problem, but Alpha pockets are tight. Leave them tight. Don't "uniform" them - I promise you will be doing work and wasting great brass.

 

[Straightshooter1]

Been reading about the debate on primer seating depth vs accuracy (yes, I have a reloading problem). Not to get involved in that debate, but I use Alpha and Lapua 6mm Dasher brass (6 br fire formed). The primers in the Alpha brass actually seem to go in the pocket with a "step" in the seating where it gets a little tighter. Using a FrankFord Arsenal adjustable primer tool set to seat primers @.007 in the Lapua brass, wont seat the primer in the Alpha brass but .002 at most. Has any of you had this experience? rsbhunter

Did you measure the primer pockets to see what difference there might be?

I recently got some Peterson brass and found that their LRP's were at .129" deep compared to my Lapua at .121". This difference will certainly have a very similar result.

 

[Fuj]

I'm not sure I understand your concern or problem, but Alpha pockets are tight. Leave them tight. Don't "uniform" them - I promise you will be doing work and wasting great brass.

You uniform the pockets for depth.

 

[LVLAaron]

You uniform the pockets for depth.

You aren't going to get a uniforming tool in an alpha pocket without chowdering the walls of the hole. They're tight.

 

[jvw2008]

21st Century uniformer will work nicely in Alpha pockets without “chowdering” the walls. You will also get different pocket depth measurements depending on what tool you use to acquire that dimension. The Accuracy One (CTK) tool used with a dial indicator comes with a concave tip that gives the true depth of the rim of the bottom of the primer cup.

 

[Fuj]

You aren't going to get a uniforming tool in an alpha pocket without chowdering the walls of the hole. They're tight.

I had absolutely no problems with their large primer brass. Plus
uniforming shanks can be had in any width needs. Harrels made mine,
along with the tool for flash holes.

 

[LVLAaron]

Let me know what the variances are in Alpha.

 

[6MMsteve]

I do nothing to pockets anymore, buy good brass and I leave them be, uniform the flash hole front n back that's it, but someone in high comp may disagree but it's me the way I do it

 

[wedgy]

I could not get Fed 210's to seat in some brass and found the diameter of CCI's to be smaller and then did seat

Chart with the diameter difference; https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/

 

[jvw2008]

21st Century uniformer will work nicely in Alpha pockets without “chowdering” the walls. You will also get different pocket depth measurements depending on what tool you use to acquire that dimension. The Accuracy One (CTK) tool used with a dial indicator comes with a concave tip that gives the true depth of the rim of the bottom of the primer cup.

Sorry that should read: “bottom of primer pocket”

 

[BartsBullets]

Been reading about the debate on primer seating depth vs accuracy (yes, I have a reloading problem). Not to get involved in that debate, but I use Alpha and Lapua 6mm Dasher brass (6 br fire formed). The primers in the Alpha brass actually seem to go in the pocket with a "step" in the seating where it gets a little tighter. Using a FrankFord Arsenal adjustable primer tool set to seat primers @.007 in the Lapua brass, wont seat the primer in the Alpha brass but .002 at most. Has any of you had this experience? rsbhunter

Yes, the Alpha Brass has a physical step in it, which makes it harder (more pressure) to seat primers.

Bart

 

[jackieschmidt]

What is the purpose of the step?
Just curious, as the only brass I have used in the past 20 years is Lapua.

 

[jelenko]

I could not get Fed 210's to seat in some brass and found the diameter of CCI's to be smaller and the did seat

Chart with the diameter difference; https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/View attachment 1356833

Hmm. Recently I switched from Rem 7 1/2's to CCI 450's. The 450's were much tighter in the same lot of brass. I'm wondering if one of them has modified their production in the past 5-6 years? [For Remington, I mean before Vista bought them]

 

[fkimble@charter.net]

I don't put a lot of trust in that primer chart, especially that 4th decimal place. The chart has been around for years. Different lots I'm sure can vary. Over the years as equipment wears so does the various dimensions.

Frank

 

[mikecr]

If Alpha got the pocket wrong, what else did they get wrong?
I would look at the cases closer.

 

[Fuj]

I bought some of the early on Alpha Creedmoor brass ( LRP ) to do
a wild cat when Alpha first came online. Brass was overly soft, and
primed with ease with BR2 primers. I realized no step in the pocket,
when uniforming. The pockets were very consistent fresh. Not quite
so after the first fire forming. I attributed that to that batch of brass
not being hard enough in the head. It took little effort to size the
brass. They may have changed their specs since opening shop, but
other then this batch, I wont by anymore.

Without calling Alpha, do they step both LRP's and SRP's ?? I do not
shoot SRP brass, so would not know what Alpha does in that area.

 

[boltfluter]

In my experience, RP primers have always seated easier than CCI450 primers. Not necessarily bad, just different.
Paul

 

[BartsBullets]

What is the purpose of the step?
Just curious, as the only brass I have used in the past 20 years is Lapua.

To make the primer pocket stronger. I shot a alpha case 50 times in a row with an average velocity of 3020 shooting 105gr in my 6BRA. That’s a fairly stiff load. After the 50 firering the primer pocket was still good to go.

Bart