Jesse Heywood
Member
Put a small radius on the corner of the firing pin. Your pin is punching a hole, just like a paper punch. Ever try punching holes with a dull punch?
Notes on "Pierced" Primers
- Thread starter denton
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mokin
Member
I'm curious. Among the three loads, which one was the most accurate?
denton
Member
I don't think that is the case. The pin is not punching a hole. The primer cup is thin and is extruding back into the firing pin hole, as Slamfire said. If the pin were punching the hole, I believe that it would make holes regardless of powder charge, and it does not.
denton
Member
Haven't gotten that far yet. Weather here is getting to be about right for a nice range trip to sight in a new scope. Might have time to assess while doing that.
Jim Watson
Member
Different gun, different loads, but my attempts at .223 F class were maximum to over in an AR action and I saw no such primers.
NMexJim
Member
Those primers are all showing flow signs to my eye. Shiny around the head-stamps. Punch out a couple of those and let’s see if the sides of the primers are eroded.
denton
Member
That is an interesting observation. Thanks.
JFrank
Member
Post a picture of your bolt face please.
Nature Boy
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Folks, there's really no mystery here. CCI 400's are simply the wrong choice for .223. The cups are too thin
JFrank
Member
I want to see a picture of that big ol nasty firing pin / pin hole... Yuk
Charlie98
Member
I guess I have to ask... and maybe I'm splitting hairs...
Hoary reloading lore has it that CCI's have the hardest cups of the major American primers, that's why so many accuracy shooter shun CCI's for bench work. So, CCI #400's are bad, but CCI #450's and #41's are good? I find it hard to believe the minor thickness change between SR and SRM primers would alleviate the piercing shown in the OP's #1.
I've used #400's in some midrange 5.56mm loads without problems, but I was not pushing max data. I use either #450's or #41's as a matter of course in 5.56mm, now, regardless.
Someone else mentioned WSR's for heavy .223/5.56mm loads... I consider Winchester primers pretty much garbage, for reasons I won't enumerate here. In fact, I have a box right here to ship the last of my Winchester primers back to them...
Nature Boy
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But the data says otherwise, particularly for the CCI 400s
https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/
From the article:
"What does all this mean to the reloader?
– Cases that utilize small rifle primers and operate at moderate pressures (40,000 psi) can use CCI 400, Federal 200, Rem 6 1/2, or Win SR. Such cases include 22 CCM, 22 Hornet and the 218 Bee. Other cases that use the small rifle primer can use the above primers only if moderate loads are used. Keep to the lower end of reloading recommendations.
– Cases that utilize small rifle primers and operate at higher pressures (55,000 psi) should use CCI 450, CCI BR4, Fed 205 and Rem 7 1/2."
"What does all this mean to the reloader?
– Cases that utilize small rifle primers and operate at moderate pressures (40,000 psi) can use CCI 400, Federal 200, Rem 6 1/2, or Win SR. Such cases include 22 CCM, 22 Hornet and the 218 Bee. Other cases that use the small rifle primer can use the above primers only if moderate loads are used. Keep to the lower end of reloading recommendations.
– Cases that utilize small rifle primers and operate at higher pressures (55,000 psi) should use CCI 450, CCI BR4, Fed 205 and Rem 7 1/2."
They are also thin, and not suited for .223 pressures. See link above
So do I. I won't use any of their reloading products, especially their primers.
Jim Watson
Member
So what primers do Federal and Winchester use in their factory rifle ammo?
denton
Member
Exactly!
Some people use regular primers and have no problem. In my bolt action 223/5.56, they work fine, probably because it doesn't have a floating firing pin. As I worked up my load, it became apparent that they weren't going to work in my AR.
There is no reason to believe that the cartridge is at excess pressure. The load is normal. The MV is normal. The primer cup is too thin for this application, just like the book says.
The point of the original post was to show how "pierced" primers happen. The firing pin does not punch a hole in the primer. The primer extrudes back into the firing pin hole, and often breaks off around the base of the extrusion, leaving a round hole. Sometimes, the extrusion will stay attached. An example of each of those two cases is shown in the photo.
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JFrank
Member
I'll post this as part of the discussion not as a derailment.
A friend of mine and two time 1000 yard BR champion, prior to the current shortages of course tested primers using an abbreviated ladder charge test, the results were that each primer tested grouped significantly different. He would consider these results while developing the load.
Another highly respected tester has posted that in his experience the Receiver seems to be the main factor in determining a primer not the barrel.
A friend of mine and two time 1000 yard BR champion, prior to the current shortages of course tested primers using an abbreviated ladder charge test, the results were that each primer tested grouped significantly different. He would consider these results while developing the load.
Another highly respected tester has posted that in his experience the Receiver seems to be the main factor in determining a primer not the barrel.
mokin
Member
Please keep us posted. I'm sure I'm not the only person interested in your results. You've started off with good photo documentation. We all have a great opportunity to learn something here.
Blue68f100
Member
I've blown primer when the bolt FP clearance is too large giving too much clearance. Once I replaced the bolt with proper FP clearance the load was fine. This was in a AR-10 6.5 CM that I built. All my brass has the small primer pockets. The FP hole was 0.004" larger than the FP. Normal clearances should be in the 0.001-0.0015" range for that small pin. There was no indication of over pressure. In both cases the primer had not flatten at the edge.
I mentioned WSR, but I sure didn't mean to infer they were good for heavy loads. I mentioned how they are made with .021" vs the CCI 400's which are made with .020" material. Which is only very slightly thicker. Very slightly. And I'm aware of the reputation of Winchester primers, which I'd never bought Winchester primers previously. If I had my druthers, I'd have nothing but CCI #41 in my limited inventory. But as it is, I'm just glad to have some SRPs at all. I will load accordingly, of course.
Sure thing. You will notice I'm a new AR15 owner. That's a virgin boltface. I've not fired it yet. I have factory loads to start with, but I like reloading. I've got supplies to make many .223 rounds, but I've only been gathering up to now.
We are going afield of the original post, which was by someone else, about something else.
243winxb
Member
View attachment 988929 The CCI 400 & Rem 6 1/2" are only good up to 40,000 PSI.
243winxb
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243winxb
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Charlie98
Member
That's exactly what happened with my Winchester LRP's... they were not high pressure loads. That is a primer cup failure, not a piercing, so to speak.
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