Primer Primer?

[choprzrul]

Reloading seems to be a lifelong exercise in learning new things.

I never used to give which primers I used much of a thought. Granted, I didn't cross over between standard and magnum primers, but if I switched between brands of large rifle primers, for example, I figured all was well and good. Deer got shot and died while seemingly caring little for which brand of primer I was using.

Nowadays I'm working towards shrinking my group sizes and doing a lot more reading and researching. Based upon what I have been reading, not all primers are created equal.....go figure

Using the large rifle primer as an example again, it is my understanding that generally they fall into these 'heat' ranges:

Mild: Remington
Middle: CCI and Federal
Warm: Winchester

Is the above generality close to being accurate? It makes me wonder how close a 'standard' Winchester WLR and a Federal 215 'magnum' primer are in how they ignite powder?

What prompted this thread creation was my load pursuit for my new Savage 110 with a Proof Research barrel. I'm getting ready to load a ladder using Norma 202 powder....so I consulted their load manual and noticed that it is calling for a Winchester Magnum WLRM primer for all of their 308 Winchester loads. Does Norma powder really need magnum powders to light, or are those Nordic countries cold enough that standard primers don't get the job done?

Anyway....all of this prompted me to go looking at load data for the 308 from different sources for what type of primer they call for. Here is a sampling:

Norma: WLRM
Hodgdon Load Data online: Federal 210M match
Alliant Load Data online: Federal 210
Western Powders v6.0: Winchester WLR
Speer 172gr Impact: Federal 210
Barnes Load Data online: Federal 210
Nosler Load Data online: Federal 210 and WLR

Anyway, I don't have WLRM primers to use, but I do have some Federal 215M match primers.

This brings up another question....at some point I read that using magnum primers in a smaller case can create 2 separate pressure peaks. One when the primer ignites and a second one milliseconds later when the powder ignites. Normally I wouldn't give this much thought, but they were talking about the possibility of the first pressure event moving the bullet forward to the rifling and then the second pressure event having to get that bullet moving again when it has already engaged the rifling. I don't have a link, but I'm wondering if this is possible/really a thing??

I suppose if I seat the bullet with enough tensions, the primer won't get it moving

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Hat tip to AandO below in post #6. He posted a link to a great resource regarding primers.
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[curtnelson226]

Personally, I've done some extensive testing on match loads utilizing several different primers from standard cci, br4, rem 7 1/2s, to win srp and generally found that the difference in accuracy is negligible. Ymmv, but I've squeezed out much tighter groups from reducing seating depth to .015 off the lands and putting more time into case prep work like annealing... still I've found that me as the trigger man is still the biggest factor in accuracy.

Sent from my SM-N981U using Tapatalk

[choprzrul]

Personally, I've done some extensive testing on match loads utilizing several different primers from standard cci, br4, rem 7 1/2s, to win srp and generally found that the difference in accuracy is negligible. Ymmv, but I've squeezed out much tighter groups from reducing seating depth to .015 off the lands and putting more time into case prep work like annealing... still I've found that me as the trigger man is still the biggest factor in accuracy.

Sent from my SM-N981U using Tapatalk

Thinking about that whole 'Nordic' thing with cold temps....I wonder if the magnum primers give more reliable ignition.....or do they use them for more uniform powder performance over a wide range of temperatures?

I might see a swing in temps from 70 degrees here to 15 degrees deer hunting in Nebraska.

Too dang many variables and unknowns without real world testing. I think a guy would have a barrel worn out by the time he covered all bases :-(

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[LynnJr]

When you chronograph your loads your extreme spreads will look like an hour glass shape.
If you look at the skinny part of the hourglass shape your extreme spread should be single digits if all is well.

If you get 35 fps extreme spreads your primers are not working or your using the wrong powder if everything else is right with your case prep.
Primers are just a tuning tool and they are cheap so use what works according to your chronograph readings.

[JackEllis]

still I've found that me as the trigger man is still the biggest factor in accuracy.

Absolutely.

I'm not going to minimize the importance of ammunition that consistently puts the bullet in the same place (or close to it) but at the end of the day if you're hunting, your ability to keep the rifle steady is a lot more important than getting groups to shrink from an inch to 3/4 inch. If you're hunting and you can't get ammunition that shoots bigholes, then the answer is to get closer to your prey.

[AandO]

HEY MODS, THIS NEEDS TO A BE STICKY

https://www.snipershide.com/shooting/threads/a-primer-on-primers.6936610/

[choprzrul]

When you chronograph your loads your extreme spreads will look like an hour glass shape.
If you look at the skinny part of the hourglass shape your extreme spread should be single digits if all is well.

If you get 35 fps extreme spreads your primers are not working or your using the wrong powder if everything else is right with your case prep.
Primers are just a tuning tool and they are cheap so use what works according to your chronograph readings.

Interesting and thank you for posting....it prompted me to go back and look at my last 2 load ladders I've shot for this new 308.

Here are my extreme spread numbers:

CFE223 Powder
5
31
21
27
13
9
11
3
27
33
1
21

AA2520 Powder
20
51
51
43
21
49
10
16
29
38
10
54

I should note...that while the AA2520 had larger ES, the average of all group sizes were about 20% smaller compared to the CFE223 ladder. These group sizes are across 12 different powder charge weights in 1% increments and shooting 3 shot groups for each powder weight. I plot each shot into PointBlank Ballistics software using a caliper to plot each hole in the target....so these numbers should be very close:

CFE223 average group size: 1.10"
AA2520 average group size: 0.89"

I just got a shipment of Norma 202 powder and found some Winchester WLRM primers, so I think I'm going to give that a whirl.