5.56 primer seating depth issues

[Oldgoat03]

I have been reloading pistol for a few years and have just begun loading 5.56/223 for my AR. I have read a lot and been progressing slowly/carefully as I learn the many steps of reloading rifle cartridges.

I am reloading my own once fired Federal 55 gr FMJ 5.56 brass.

After depriming, resizing, swaging & trimming I am now set to prime, charge & seat new bullets.

As I seated the first few primers (CCI 400 Small rifle) I noticed they weren't seating as deep as normal. Rather than being just below the case lip they are flush and perhaps even .001 high. I tried seating the primers more firmly with little/no affect. I tried re-swaging the pockets and then seating the new primer also without change.

At that point I called Dillon to ask if my new Super Swage could be out of adjustment and causing the issue. After talking through the situation the Dillon Tech was convinced it was the CCI primers which he said were taller and much harder than the Federal primers in the factory ammo.

He suggested I measure the CCI LRP height and compare it to a Federal. I don't have any other small rifle primers so used a Win Small pistol for comparison. Findings are CCI SRP 0.1175" tall / Win SPP 0.1155" tall. I was surprised at the consistent (measured several) .002" difference! I was under the impression (mistakenly it seems) that primer dimensions were standardized!?

So as an experiment I seated one of the WPP in a case. It seated just like the factory ammo primers.

I have uploaded a few photos that hopefully show what I am describing.

So now I have some questions that I hope you can help with:

1) Can I safely use my CCI 400 primers seated deeply but as they are?

2) If they can't or shouldn't be fired seated as is ... is there a fix to the brass to enable deeper seating?

3) Are primer heights truly not standardized?

3) Should I just buy Federal small rifle primers as the Dillon tech suggested?

I am hoping you experienced 5.56/223 re-loaders have already encountered this situation and can advise me.

Thanks in advance for your help!
Bob

 

[Walkalong]

There is no reason you shouldn't be able to seat those below flush. The Dillon swage tool only removes crimp, it doesn't open up the diameter of the pocket. That isn't the problem.

How are you seating the primers? Hand tool? Press?

 

[Reloadron]

I seat my primers using a hand tool (Lee or RCBS) and always seat a primer till it bottoms out in the pocket:

Note the typically .003" gap below the white business card and the seated primers.

Primers and primer pockets do have tolerances and specifications they should meet:



You can measure the height of the primers and depth of the primer pockets. That should tell you what you have and when the primers are seated till they bottom out what you end up with.

Ron

 

[Oldgoat03]

Walkalong thanks for your reply. I am seating primers on my Dillon 550 press and have never had this issue before.

 

[X-Ring]

If you primer pockets are a little shallow or not flat bottomed, you might want to try a primer pocket uniforming tool.
http://www.midwayusa.com/product/764406/redding-primer-pocket-uniformer-tool-small
This is Redding’s but it is a bit pricey.

 

[Oldgoat03]

Xring its interesting you mention non-uniform pockets because that is what I think I'm seeing. The pockets appear to have a bit of a slope in the bottom. I thought I was imagining it but will get a pocket uniform tool and try it.

I will continue to look things over tomorrow with fresh eyes.

Thanks again for the help.
Bob

 

[Nature Boy]

I am seating primers on my Dillon 550 press and have never had this issue before

Double check your shell plate to make sure its snug. I had this problem on my 650 and realized that there was too much slack

 

[spitballer]

I use a Lee hand primer and I squish it all the way closed, turn the case 180 degrees and squish again. Squeezing until the primer just touched the bottom just wasn't cutting it when primers weren't flush even after rotating and re squeezing. I've never had problems after doing the full squish, although it took some nerve and a pair of safety glasses to try it the first time. The Lee manual does not recommend fully closing the primer with both thumbs, but I will not settle for a primer that is not at least flush. I've read some posts by members who've said that primers should be "primed" or "activated" by seating fully into the pocket but I don't know anything about this, all I know is that if I want my primers flush I have to do the 'full squish'.

 

[Oldgoat03]

After sleeping on it I tried seating some more of the CCI SR primers and with much effort some seated to just below flush. It seems like a lot of pressure (perhaps too much) is needed to accomplish below flush seating on these once fired Federal 5.56 cases.

Next as suggested I measured the pocket depth on several of the Federal cases and they are not uniform. One side of pocket will be .111" deep and the other side of the same pocket can be .120". I'm not sure what caused this pocket depth deformity in the once fired Federal cases. Perhaps they were made that way. I measured a couple of other head stamp mixed brass and found it to be much more uniform. I tried seating a few of those and primers seat just just below flush as they should.

It seems the thing to do in order to reuse this Federal brass is get a tool and uniform the primer pockets.

Does this make sense?

Thanks again for your help.
Bob

 

[sellersm]

Makes sense to me cuz that's what I do!


Sent from my fat fingers using Tapatalk

 

[LiveLife]

I use CCI #400, CCI #41, Winchester SR, Tula SR and Tula .223 primers and prefer to seat primers around .004" below flush, especially for auto-loading rifles with floating firing pins to avoid slam fires. While I prefer to hand seat primers for rifle cartridges, I also press prime using Dillon 650/several Pro 1000s and able to seat various brand primers to slightly below flush.

I have found unmodified primer pocket depth to vary among different headstamp cases which results in varying primer seating depths but you can seat below flush first by seating the primer to the bottom of the pocket where anvil feet contact the pocket bottom then next seating deeper to push the anvil feet up into the primer cup so anvil tip sets against the priming compound.

I have even done primer seating test to .006" - .008" crush depth where the primer cup is flattened and all of them have fired without issues, so feel free to seat them until they are below flush - http://www.thehighroad.org/showthread.php?p=7810685#post7810685

Comparison picture showing .004" vs .008" primer seating depth

 

[Oldgoat03]

Success!

I used my FA pocket cleaner on the cases and it was slow but did the trick. I am now able to seat the CCI 400 primers to .004" below flush with the case head. With that limited success I was able to begin my work up for my S&W M&P 15.

I went with 2.250" OAL

CFE223 powder, CCI 400 SRP, Xtreme 55gr FMJ

10 rds each at 24.7gr, 24.9, 25.1, 25.3, 25.5, 25.7

I hope to continue the workup loading tomorrow stopping well short of max until I can get to range with a chrono. I also plan to shoot the first 5 of each loading as singles for safety since this is my first reloading for an AR. Assuming the first 5 rds shoot normally I will then load and shoot the 2nd set of 5 from the mag.

I still plan to get a primer pocket uniform tool that will screw into my FA case prep center but no one had one locally. That will speed up processing my Federal brass.

Thanks again for all your insight and suggestions!
Bob

 

[tonyjr]

Thanks -
I now have 2 nephews who want a 223 .
I only use CCI primers and go flush .
In the past I have had primers high and low
Thats when I started using only CCI and cleaning
both primer flash holes and primer pockets before
tumbling .
If I do reload 1000 rounds , 990 would be pistol .
Thanks again

 

[tcoz]

If you primer pockets are a little shallow or not flat bottomed, you might want to try a primer pocket uniforming tool.
http://www.midwayusa.com/product/764406/redding-primer-pocket-uniformer-tool-small
This is Redding’s but it is a bit pricey.

+1....I ran into this problem when I started loading 30 carbine and it was leading to very sporadic fail-to-fire issues. I finally determined that primer seating depth was the problem and as soon as I started uniforming the primer pockets the problem resolved.
I like the RCBS uniformer and attached it to my FA Case Trim & Prep Center in place of the primer pocket cleaning brush.